Under mass conversions, connections between **grams, moles **and **molecules** are established.

The **mole** is the chemical unit for the amount of a substance and serves as the bridge that connects grams to molecules, atoms, formula units and ions.

**Concept:** Avogadro’s Number, Moles, Molecules & Atoms

Before we begin, we should realize that mass conversions are going to play a very important and essential role in almost all the calculations we're going to do this semester.

We're going to start off by saying that the mole is the chemical unit for the amount of a substance. What exactly does this mean? Instead of a chemist ordering a hundred pounds of a particular element, a scientist could easily say 'I need 10.12 moles of carbon' or '100 moles of nitrogen'. It's basically a certain way that chemist communicate with each other to designate the amount, the weight they need of a particular element or compound.

We're going to say that one mole which you can write as this way, one mole contains 6.022x1023 entities. We're going to say that this special number has a name to it. This special number is known as Avogadro's number. When we say the word 'entities', entities means different things. When we say entities, entities can mean atoms, molecules or particles.

We're going to say we use atoms when we're dealing with a single or individual element. If I want 1,000 atoms of oxygen, I'm only talking about single oxygen. Remember oxygen can exists as a diatomic molecule, but here we're not talking about the molecule, we're talking about just the atom.

We're going to say we use molecules or particles when dealing with more than one element together or a compound, so just remember the difference. Atoms go with a single elements, molecules or particles goes with more than one element together or a compound. Compounds remember are just different elements combined together.

The words **atoms** and **ions** are used when talking about a single element and the words **molecules** and **formula units** are used when talking about more than one element together.

**Concept:** Atoms to Moles to Grams

How does this relate to our calculations we're going to do this semester?

Here we have two good examples of when do we use atoms versus when do we use molecules or particles. If we take a look, we say we have 6.022x1023 atoms of iron. Iron is there by itself, so that's why we're using the term atoms. Remember that's Avogadro's number. That number is always equal to one mole of whatever we're talking about. Since we have this many atoms of iron, that means we have one mole of iron.

We're going to say also that one mole of something is related to its weight. It's atomic mass which you'll find on your periodic table. If you look at your periodic table right now, look for iron, it's a transition metal. One mole of iron is equal to its atomic mass that you see on your periodic table. If you take a look, you'll see 55.85. That's representative of its atomic mass unit or we can say 55.85 grams per mole.

What we need to realize here, that there's a connection. We can go from atoms to moles to grams. I show you double arrows meaning we can go either way. So we can go from atoms to moles or moles to atoms. We can go from moles to gram or grams to moles. The arrows go both ways.

What we should realize here is that moles play the connection that's between atoms and grams. Remember you can’t go straight from atoms to grams without having first go through moles.

**Example:** Determine the mass (in grams) found in 7.28 x 10** ^{28}** nitrogen atoms.

**Concept:** Molecules to Moles to Grams

We've seen how atoms work. Now let's see how molecules work. We're going to start out again with Avogadro's number, but this time in terms of molecules of water. Remember that Avogadro's number is equal to one mole of whatever we're talking about, whether it be an atom, whether it be a molecule, whether it be particles, so that's equal to one mole of water.

One mole of any substance, whether it be an individual element or a compound, one mole of anything is equal to that objects molecular weight, its atomic mass. Here we have a mixture of different elements together, we have two hydrogens, we have one oxygen and water. To find out its total mass, we're going to add up each individual part.

We have two hydrogens, right? Because this little two here with the H, if you look on your periodic table, look for the atomic mass of hydrogen. When you look at it, you'll see that on your periodic table, its 1.008 grams and there are two hydrogens, so multiply that number times two. So that's 2.016 grams per mole.

Also, we have one oxygen which weighs 16 grams according to our periodic table, so that's 16 grams per mole. When you add those two numbers up together, that gives you the 18.016 grams per mole or 18.016 atomic mass units. That's where that number came from. We looked up each of the atomic masses of each individual element and then added them up together to get our answer.

Remember, Avogadro's number is always equal to one mole of whatever we're talking about. One mole of anything is just equal to the total mass of that object. If we take a look at this example, we're going to say it says, 'Determine how many molecules of carbon dioxide are found in 75 grams of carbon dioxide?'

Now, you should notice that this chart is similar to the one we just saw, except now instead of seeing atoms, we see molecules. You could also put particles in there too. Remember, there's a connection between molecules at moles, you can go from molecules to moles or moles to molecules and again there's a connection between moles and grams.

**Example:** Determine the how many molecules of carbon dioxide, CO_{2}, are found in 75.0 g CO_{2}.

**Problem:** If the density of water is 1.00 g/mL at 25^{o}C. Calculate the number of water molecules found in 1.50 x 10^{3} µL of water.

**Problem:** Calculate the number of oxygen atoms found in 783.9 g in copper (II) sulfate pentahydrate, CuSO_{4} x 5 H_{2}O.

**Problem:** The density of the sun is 1.41 g/cm^{3} and its volume is 1.41 x 10^{27} m^{3}. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?

**Problem:** A cylindrical copper wire is used for the fences around a house. The copper wire has a diameter of 0.0750 in. How many copper atoms are found in 5.160 cm piece? The density of copper is 8.96 g/cm^{3}. ( V = π x r^{2} x h )

Calculate the mass (in g) of a single maltose molecule (C12H22O11).

Express your answer using four significant figures

Watch Solution

Ascorbic acid, or vitamin C (, molar mass = 176 g/mol), is a naturally occurring organic compound with antioxidant properties. A healthy adult's daily requirement of vitamin C is 70-90 mg. A sweet lime contains 2.88 times 10^-4 mol of ascorbic acid. To determine whether the ascorbic acid in a sweet lime meets the daily requirement, calculate the mass of ascorbic acid in 2.88 x 10^-4 mol of ascorbic acid. Express the mass in grams to three significant figures.

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How many moles (of molecules or formula units) are in each sample?

a. 62.20 g CF_{2}Cl_{2}

b. 21.3 kg Fe(NO_{3})_{2}

c. 0.1911 g C_{8}H_{1}_{8}

d. 130 kg CaO

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The daily dietary energy requirement for an adult is 2.00 x 10 ^{3} kcal (1 ca = 4.184 J). This is equivalent to

a. 47.8 x 10^{4} kJ

b. 8.37 x 10^{3} kJ

c. 8.37 x 10^{3} J

d. 2.00 x 10^{3} kJ

e. 478 kJ

Watch Solution

How many 150-mg aspirin tablets can be made from 15.0 kg of aspirin?

a. 100,000

b. 1,000,000

c. 10000

d. 10,000

e. 10,000,000

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a. How many moles of atoms are in 8.00 g of 13C?

b. Based on your answer in Part A, calculate the number of atoms in this amount of 13C?

c. Based on your answer in Part B, how many electrons are in this amount of 13C?

d. Based on your answer in Part B, how many neutrons are in this amount of 13C?

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a. Calculate the formula weight of ethanol, C _{2}H_{5}OH?

b. Calculate the formula weight of Mg(NO _{3})_{2}?

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How many moles of atoms are in 9.00 g of ^{13}C?

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How many grams of CO _{2} are in 2.1 mol of the compound?

a. 21.0 g

b. 44.0 g

c. 66.0 g

d. 92.4 g

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Determine the mass of oxygen in a 7.2 g sample of Al _{2}(SO_{4})_{3}.

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Find the number of ibuprofen molecules in a tablet containing 200.0 mg of ibuprofen (C_{13}H_{18}O_{2}).

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In the gaseous state, chlorine exists as a diatomic molecule Cl _{2} (Molar mass = 70.9 g/mol). Calculate the number of moles of chlorine present in 150 g of chlorine gas.

Express the quantity in moles to three significant figures.

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How many moles of water, H_{2}O, contain 2.0 × 10^{22} molecules of water?

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What is the mass, in grams, of 1.24 mol of water, H _{2}O? Express the mass in grams to three significant figures.

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Assume the ideal gas constant, R, has a value of .08206 (L * atm)/(mol * K). Convert this value into expressions for R in terms of J/(mol* K), (cubic meters * Pa)/(mol * K), (L * bar)/(mol * K), and J/(molecule * K).

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How many molecules are contained in the 254 grams of CH _{4}? The molar mass of CH_{4} is 16 grams/mole.

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Calculate the molar mass of ammonium phosphate (NH _{4})_{3}PO_{4} to correct sig. fig.

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The molecular weight of ethanol (C_{2}H_{5}OH) is 46.1 and the density of absolute (100%) ethanol = 0.79 g/mL.

During a romantic candlelight dinner a 75 kg person drinks a bottle (750 mL) of wine in the space of 3 hours. Ethanol is metabolized at a constant rate of 120 mg per hour per kg body weight, regardless of its concentration. A 75 kg person contains about 40 L of ‘water’. Ignore the metabolism, and assume the water content of the person remains constant.

a)What is their blood alcohol content (mg/100 mL blood) at the end of the dinner?

b)How long will it take for their blood alcohol level to fall below the legal limit of 50mg of ethanol per 100mL of blood (0.05%)?

Watch Solution

The molecular weight of ethanol (C_{2}H_{5}OH) is 46.1 and the density of absolute (100%) ethanol = 0.79 g/mL. The legal limit for a driver’s blood alcohol is 50 mg of ethanol per 100 mL of blood (referred to as a blood alcohol content (BAC) of 0.05%). And a bottle of wine is 14% ethanol by volume.

How much wine (standard serving size = 100 mL) could a 75 kg person drink and remain under the legal limit? The blood alcohol content will be equivalent to the alcohol content in the total ‘water’ component of the human body. A 75 kg person contains about 40 L of ‘water’. Ignore the metabolism, and assume the water content of the person remains constant.

Watch Solution

Calculate the molar mass of ALUM, KAl(SO _{4}) _{2 }**. **12H_{2}O or potassium aluminum sulfate dodecahydrate. Be sure to include the twelve waters of hydration in the molar mass.

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The molar mass of potassium phosphate (K _{3}PO_{4}) is

A) 173.17

B) 251.37

C) 212.27

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How much does one sucrose molecule weigh in grams?

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What is the molar mass of aspirin, C_{9}H_{8}O_{4}?

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Calculate the molar mass of potassium hydroxide (KOH).

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What is the molar mass of calcium phosphate, Ca _{3}(PO_{4})_{2}?

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Calculate the molar mass of Cl _{2} if 1.27 x 10^{22} molecules of gaseous Cl _{2} have a mass of 1.5g.

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Calculate the molar mass of sodium chloride, NaCl (from the periodic table Na = 22.99 and Cl = 35.45).

a) 6.745 g/mole

b) 58.44 g/mole

c) 74.55 g/mole

d) 67.45 g/mole

e) 19.00 g/mole

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Determine the molar mass of potassium hydrogen phthalate (KHP). The molecular formula is KHC_{8}H_{4}O_{4} .

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The molar mass of HNO_{3} is 63.01g/mol, perform each of the following conversions

i) convert 13.9 g of HNO_{3} to moles and

ii) convert 2.507 moles of HNO_{3} to grams

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How many moles are there in 7.0 mL of N,N-dimethylaniline? Density of N,N-dimethylaniline is 0.956 g/mL and its molar mass is 121.19 g/mol. Show your work.

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What is the molar mass of magnesium hydroxide, Mg(OH) _{2}, a common antacid?

(A) 58 g/mol

(B) 56 g/mol

(C) 42 g/mol

(D) 41 g/mol

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Calculate the error for the molar mass of acetic acid, CH _{3}CO_{2}H. The atomic masses for each element are C = 12.0106 ± 0.0010, H = 1.00798 ± 0.00014, and O = 15.9990 ± 0.0008

Watch Solution

What is molar mass of Na _{2}CO_{3}?

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If you have 20.0 g of carbon dioxide gas, how many molecules of CO _{2} do you have?

A) 4.30 x 10^{23} molecules of CO_{2}

B) 2.74 x 10^{23} molecules of CO_{2}

C) 5.30 x 10^{26} molecules of CO_{2}

D) 1.46 x 10^{-21} molecules of CO_{2 }

E) 7.55 x 10^{-25} molecules of CO_{2}

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The empirical formula of a chemical compound is C_{3}H_{8}O_{3}. Its approximate molar mass of 94 g/mol was found by experiment. Calculate its exact molar mass.

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Consider the compound C_{2}H_{4}O_{2}. How many grams of oxygen are in 3.0 grams of it?

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You drank 100.0 g of water. This quantity of water contains hydrogen that is equivalent to (x) moles of hydrogen (H_{2}).

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You ate 5.0g of sugar (C_{6}H_{12}O_{6}). This quantity of sugar contains oxygen that is equivalent to how many moles of ozone (O_{3})?

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You ate 97.0g of NaCl. How many sodium ions does this quantity of NaCl contain?

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If you drink 225.0 g of pure water, about how many molecules of water do you drink?

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How many atomic mass units is 1 mole of water?

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Your car is 4.48 metric tons. How many times more massive is your car than an aluminum (Al) atom?

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How many moles of carbon atoms are present in a piece of diamond which has a volume of 1.00 cm^{3}? The density of diamond is 3.53 g/cm^{3}.

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Calculate the average mass, in grams, of an O_{2} molecule.

a. 32.0

b. 2.00

c. 2.66 x 10^{-23}

d. 1.88 x 10^{-22}

e. 5.31 x 10^{-23}

Watch Solution

Determine the mass (g) of solute required to form 275 mL of a 0.4230 M KClO _{3} solution.

a. 1.97

b. 4.21

c. 14.3

d. 12.2

e. 19.6

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6.02 x 10^{21} molecules of an unknown substance X has a mass of 11.0 grams. What is the molar mass of X in g/mole?

(A) 110 g/mol

(B) 220 g/mol

(C) 1100 g/mol

(D) 2200 g/mol

(E) cannot be determined without the formula of X

Watch Solution

Calculate the number of nitrogen atoms in 240. g of ammonium nitrate.

(A) 2.01 x 10^{23} nitrogen atoms

(B) 6.02 x 10^{23} nitrogen atoms

(C) 1.20 x 10^{24} nitrogen atoms

(D) 1.81 x 10^{24} nitrogen atoms

(E) 3.61 x 10^{24} nitrogen atoms

Watch Solution

32.0 grams of the element oxygen:

(A) contain 6.02 x 10^{23} atoms of oxygen

(B) contain 1.204 x 10^{24} molecules of oxygen

(C) contain the same number of oxygen atoms as 18.0 g of water

(D) contain the same number of oxygen atoms as 72.0 g of water

(E) contain the same number of oxygen atoms as 90.0 g of water

Watch Solution

Consider the reaction of hydrogen gas (H_{2}) and oxygen gas (O_{2}) to form water. How many molecules of water will be made by the reaction of 12.0 g of O_{2} gas?

(A) 1.13 x 10^{23} molecules

(B) 2.26 x 10^{23} molecules

(C) 4.52 x 10^{23} molecules

(D) 2.26 x 10^{24} molecules

(E) 4.52 x 10^{24} molecules

Watch Solution

Calculate the number of moles in 55.0 g of magnesium hydroxide.

(A) 0.943 mol

(B) 1.33 mol

(C) 1.83 mol

(D) 2.89 mol

(E) 5.68 x 10^{23} mol

Watch Solution

What is the mass of 4.50 x 10^{22} atoms of magnesium, Mg?

(A) 0.0748 g

(B) 0.182 g

(C) 0.897 g

(D) 1.82 g

(E) 18.2 g

Watch Solution

Calcium fluoride is used to fluoridate drinking water. Calculate its molar mass in g/mol.

(A) 118.15

(B) 99.15

(C) 78.07

(D) 59.08

(E) 38.00

Watch Solution

6.02 x 10 ^{21} molecules of an unknown substance X has a mass of 2.00 grams. What is the molar mass of X in g/mole?

(A) 0.02 g/mol

(B) 0.2 g/mol

(C) 20 g/mol

(D) 200 g/mol

(E) 2000 g/mol

Watch Solution

How many fluorine atoms are present in 19.75 g of the Freon C _{2}HBrClF_{3}?

(A) 1.81 x 10^{23}

(B) 6.02 x 10^{23}

(C) 6.69 x 10^{21}

(D) 6.03 x 10^{22}

(E) 2.23 x 10^{23}

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Calculate the mass in grams of 1.505 x 10 ^{23} molecules of CH _{4}.

(A) 4 g

(B) 16 g

(C) 40 g

(D) 64 g

(E) 2.4 x 10^{24} g

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How many moles of water contain 2.22 x 10 ^{24} molecules of water?

(A) 3.69 moles

(B) 0.272 moles

(C) 2.72 moles

(D) 36.9 moles

(E) 1.34 x 10^{48} moles

Watch Solution

Calculate the number of carbon atoms in 4.56 grams of ethanol (CH _{3}CH_{2}OH).

1. 2.53 × 10^{26} atoms

2. 1.19 × 10^{23} atoms

3. 1.79 × 10^{23} atoms

4. 5.49 × 10^{24} atoms

5. 5.97 × 10^{22} atoms

Watch Solution

How many moles of lithium phosphate are in 85.7 g of this substance?

1. 0.306578

2. 0.341986

3. 0.676199

4. 0.386893

5. 0.265989

6. 0.531978

7. 0.717652

8. 0.60452

9. 0.17272

10. 0.740105

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A quantity of N_{2} occupies 62.2 L at a particular temperature and pressure. Its density is 0.900 g/L. How many moles of N_{2} are in the container?

1. 10.1 mol

2. 12.4 mol

3. Cannot be determined

4. 2.00 mol

5. 34.6 mol

Watch Solution

How many grams of chlorine are there in 22.7 g of zinc chloride?

A) 5.90 g

B) 0.17 g

C) 10.9 g

D) 14.7 g

E) 11.81 g

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How many oxygen atoms are there in 1.55 ng of Ca _{3}(PO_{4})_{2} ?

A) 3.01 x 10^{12}

B) 1.20 x 10^{13}

C) 3.01 x 10^{18}

D) 1.21 x 10^{16}

E) 2.41 x 10^{13}

Watch Solution

What mass of aluminum bromide will contain 6.3 x 10 ^{20} bromide ions ?

a) 93 mg

b) 31 mg

c) 9.3 mg

d) 27 mg

e) 273 mg

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Which of the following represents the LARGEST mass?

a) 1.20 x 10^{7} mg

b) 120 kg

c) 12.0 ton

d) 1200 lb

e) 1.20 metric ton

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What is the mass of 5.45 x 10 ^{-3} mol of glucose C_{6}H_{12}O_{6}?

A) 0.158 g

B) 982 mg

C) 3.03 x 10^{-5} g

D) 9.82 x 10^{2} g

E) 164 mg

Watch Solution

How many xenon atoms are contained in 2.36 moles of xenon?

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Calculate the molar mass for Mg(ClO_{4})_{2}.

A) 223.21 g/mol

B) 123.76 g/mol

C) 119.52 g/mol

D) 247.52 g/mol

E) 75.76 g/mol

Watch Solution

Phosphorus tribromide is a liquid with a density of 2.852 g/cm^{3}. A beaker contains 0.4875 moles of this compound.

a) What is the chemical formula of phosphorus tribromide?

b) What is the volume of liquid in milliliters (mL)?

c) How many molecules of phosphorus tribromide are in the beaker?

d) How many atoms of bromine are in the beaker?

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On the planet Tatooine, the unit of length is the zither which is defined by the relationship 7.50 cm = 1 zither. A distance of 100 meters would be _________ zithers.

a. 133

b. 266

c. 750

d. 1.33 X 10^{3}

e. 7.5 X 10^{4}

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How many grams of gold contain 1.39 x 10 ^{23} atoms of gold?

a. 0.220 g

b. 0.231 g

c. 4.33 g

d. 45.5 g

e. 853 g

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Determine the number of moles of silicon in 5.00 mg Si.

a. 1.78 x 10^{-4} mol

b. 2.40 x 10^{-4} mol

c. 0.140 mol

d. 5.62 mol

e. 5.62 x 10^{3} mol

Watch Solution

What is the average mass in grams of one atom of iron?

a. 55.85 g

b. 6.02 x 10^{-23} g

c. 9.28 x 10^{-23} g

d. 1.66 x 10^{-24} g

e. 55.85 x 10^{-25} g

Watch Solution

Which of the following samples contains the largest number of atoms?

a. 1 g Li

b. 1 g F_{2}

c. 1 g C

d. 1 g P_{4}

e. 1 g N_{2}

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How many atoms of carbon are there in 0.80 moles of C _{6}H_{4}Cl_{2}?

a. 3.9 x 10^{24}

b. 3.6 x 10^{24}

c. 2.9 x 10^{24}

d. 6.0 x 10^{23}

e. 4.8 x 10^{23}

Watch Solution

How many sodium atoms are in 6.0 g of Na _{3}N?

a. 1.3 x 10^{23} atoms

b. 3.6 x 10^{24} atoms

c. 1.217 atoms

d. 4.6 x 10^{22} atoms

e. 0.072 atoms

Watch Solution

How many sulfur atoms are present in 256 mg of Al _{2}(S_{2}O_{3})_{3}?

a. 3.95 x 10^{22}

b. 6

c. 7.90 x 10^{22}

d. 0.393

e. 2.37 x 1021

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You have 2.50 g of each of the following elements: Ca, Cu, Cs, C, and Cr. Which sample contains the largest number of atoms?

a. Ca

b. Cu

c. Cs

d. C

e. Cr

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An ionic compound has the formula MCl_{2}. The mass of 0.3011 mol of the compound is 62.69 grams. What is the identity of the metal?

a. Ni

b. Cu

c. Ba

d. Hg

e. Sn

Watch Solution

How many bromide ions are in 0.55 g of iron(III) bromide?

HINT: What does the Roman numeral mean?

a. 1.1 x 10^{21} ions

b. 3.4 x 10^{21} ions

c. 3.3 x 10^{23} ions

d. 9.9 x 10^{23} ions

e. 2.9 x 10^{26} ions

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One molecule of a compound weighs 2.03 x l0 ^{- }^{22} g. The compound is:

a) SO

b)SiO_{4}

c)Al_{2}O_{3}

d)PdO

e) none of these

Watch Solution

What is the molecular weight of glucose, C_{6}H_{12}O_{6}

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Of the following: one atom of uranium (U), one molecule of benzene (C_{6 }H_{6}), one mole of hydrogen atoms, or 6.02 × 10^{20} oxygen molecules, which one weighs the most?

1. one mole of hydrogen atoms

2. 6.02 × 10^{20} oxygen molecules

3. one molecule of C_{6 }H_{6}

4. one atom of U

Watch Solution

How many moles are in 42.6 g of water?

1. 767 mol

2. 3.04 mol

3. 2.66 mol

4. 2.37 mol

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Calculate the number of phosphorus atoms in 0.5 g of phosphorus.

1. 1.31467e+22

2. 9.72106e+21

3. 1.45733e+24

4. 7.1168e+23

5. 2.91632e+22

6. 2.01787e+22

7. 9.38124e+23

8. 5.06803e+23

9. 1.10065e+22

10. 3.49958e+22

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Suppose we have 100 g of each of the following substances. Which sample contains the largest number of moles?

1. MgCO_{3}, formula weight 84.3

2. AgCl, formula weight 143.3

3. Impossible to tell, unless we know what reaction will take place with the substance.

4. HCl, formula weight 36.5

5. H_{2 }O, formula weight 18.0

Watch Solution

Determine the volume of hexane that contains 5.33 x 10 ^{22} molecules of hexane. The density of hexane is 0.6548 g/mL and its molar mass is 86.17 g/mol.

a. 8.59 mL

b.13.5 mL

c. 7.40 mL

d. 12.4 mL

e. 11.6 mL

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Phenylenediamine (pictured below) is mainly used as a component of engineering polymers and composites. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna.

How many molecules are in a 2.00 g of phenylenediamine?

a. 1.30 x 10^{28}

b. 1.11 x 10^{22}

c. 3.59 x 10^{-20}

d. 3.07 x 10^{-24}

Watch Solution

Phenylenediamine (pictured below) is mainly used as a component of engineering polymers and composites. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna.

What mass of phenylenediamine contains 45.0 g carbon?

a. 67.6 g

b. 45.0 g

c. 72.0 g

d. 100 g

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Stearic acid (C_{18}H_{36}O_{2}) is a fatty acid found in beef and butter.

a) What is the molecular mass of stearic acid? Give your answer in units of g/mol.

b) How many oxygen atoms are present in 1.000 g of stearic acid?

Watch Solution

What mass (in kg) does 5.84 moles of vanadium (V) have?

A) 0.352 kg

B) 0.297 kg

C) 0.820 kg

D) 287 kg

E) 2.97 x 10^{3 }kg

Watch Solution

What mass (in kg) does 5.84 moles of potassium (K) have?

A) 0.352kg

B) 0.228kg

C) 0.820kg

D) 0.280kg

E) 0.632kg

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A student uses a mass balance to dispense 2.05 g of sulfur. How many moles of sulfur is this?

A. 0.0639

B. 65.7

C. 0.0152

D. 15.6

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How many atoms of nickel (Ni) are contained in 47.6 g of Ni?

A) 1.23 × 10^{23} Ni atoms

B) 2.87 × 10^{24} Ni atoms

C) 2.96 × 10^{23} Ni atoms

D) 4.88 × 10^{23} Ni atoms

E) 7.43 × 10^{23} Ni atoms

Watch Solution

What is the molar mass of aspartic acid, C_{4}O_{4}H_{7}N?

A) 43.03 g/mol

B) 70.56 g/mol

C) 133.11 g/mol

D) 197.11 g/mol

E) 206.33 g/mol

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What is the identity of substance X if 0.380 mol of X weighs 17.5 g?

A) NO_{2 }

B) N_{2}O

C) N_{2}O_{4}

D) NO_{3}

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How many oxygen atoms are there in 3.00 g of sodium dichromate, Na _{2}Cr_{2}O_{7}?

A) 9.85 × 10 ^{20} oxygen atoms

B) 0.0801 oxygen atoms

C) 6.90 × 10 ^{21} oxygen atoms

D) 4.83 × 10 ^{22} oxygen atoms

Watch Solution

What is the mass of a single chlorine molecule, Cl _{2}?

A) 35.45 g

B) 70.90 g

C) 5.887 × 10 ^{-23} g

D) 1.177 × 10 ^{-22} g

Watch Solution

What is the molar mass of calcium permanganate?

A) 199 g/mol

B) 278 g/mol

C) 216 g/mol

D) 159 g/mol

Watch Solution

How many moles of C_{3}H_{8 }contain 4.95 × 10 ^{24 }hydrogen atoms?

A) 3.09 moles C_{3}H_{8}

B) 6.58 moles C_{3}H_{8}

C) 1.03 moles C_{3}H_{8}

D) 9.73 moles C_{3}H_{8}

E) 8.22 moles C_{3}H_{8}

Watch Solution

How many moles of N_{2}O_{3} contain 2.55 × 10^{24} oxygen atoms?

A) 7.87 moles N_{2}O_{3}

B) 1.41 moles N_{2}O_{3}

C) 4.23 moles N_{2}O_{3}

D) 12.7 moles N_{2}O_{3}

E) 2.82 moles N_{2}O_{3}

Watch Solution

What is the mass of 9.44 × 10 ^{24} molecules of NO_{2}? The molar mass of NO_{2} is 46.01 g/mol.

A) 294 g

B) 341 g

C) 205 g

D) 685 g

E) 721 g

Watch Solution

What is the mass (in kg) of 6.89 × 10 ^{25} molecules of CO_{2}? The molar mass of CO_{2} is 44.01 g/mol.

A) 5.04 kg

B) 3.85 kg

C) 3.03 kg

D) 2.60 kg

E) 6.39 kg

Watch Solution

Calculate the molar mass of Ca _{3}(PO_{4})_{2}.

A) 215.21 g/mol

B) 246.18 g/mol

C) 279.21 g/mol

D) 87.05 g/mol

E) 310.18 g/mol

Watch Solution

How many C_{2}H_{4 } molecules are contained in 45.8 mg of C _{2}H_{4 }? The molar mass of C_{2}H_{4 } is 28.05 g/mol.

A) 2.71× 10 ^{20} C_{2}H_{4 }molecules

B) 9.83 × 10 ^{20} C_{2}H_{4 } molecules

C) 7.74 × 10^{ 26 } C_{2}H_{4 } molecules

D) 4.69 × 10^{ 23} C_{2}H_{4 }molecules

E) 3.69 × 10^{ 23} C_{2}H_{4 } molecules

Watch Solution

How many N_{2}O_{4 }molecules are contained in 76.3 g N _{2}O_{4}? The molar mass of N_{2}O_{4} is 92.02 g/mol.

A) 4.59 × 10 ^{25} N_{2}O_{4} molecules

B) 5.54 × 10 ^{25} N_{2}O_{4 }molecules

C) 7.26 × 10 ^{23} N_{2}O_{4} molecules

D) 1.38 × 10 ^{24 }N_{2}O_{4} molecules

E) 4.99 × 10 ^{23} N_{2}O_{4} molecules

Watch Solution

How many sodium ions are contained in 99.6 mg of Na_{2}SO_{3}? The molar mass of Na_{2}SO_{3} is 126.05 g/mol.

A) 4.76 × 10 ^{20} sodium ions

B) 2.10 × 10 ^{21} sodium ions

C) 1.52 × 10 ^{27} sodium ions

D) 1.05 × 10 ^{21} sodium ions

E) 9.52 × 10 ^{20} sodium ions

Watch Solution

Calculate the molar mass for Mg(ClO_{4})_{2}.

A) 247.52 g/mol

B) 119.52 g/mol

C) 123.76 g/mol

D) 223.21 g/mol

E) 75.76 g/mol

Watch Solution

Calculate the mass (in g) of 1.9 x 10 ^{24} atoms of Pb.

A) 2.4 × 10 ^{2} g

B) 6.5 × 10 ^{2} g

C) 3.2 × 10 ^{2} g

D) 1.5 × 10 ^{2} g

E) 3.9 × 10 ^{2 }g

Watch Solution

Calculate the mass (in kg) of 4.87 x 10 ^{25 }atoms of Zn.

A) 1.09 kg

B) 1.89 kg

C) 5.29 kg

D) 1.24 kg

E) 8.09 kg

Watch Solution

How many Li atoms are contained in 97.9 g of Li?

A) 8.49 × 10 ^{24} Li atoms

B) 5.90 × 10 ^{25} Li atoms

C) 4.27 × 10 ^{22} Li atoms

D) 4.18 × 10 ^{24} Li atoms

E) 7.09 × 1021 Li atoms

Watch Solution

How many iron atoms are contained in 354 g of iron?

A) 9.50 × 10 ^{22} Fe atoms

B) 3.82 × 10 ^{24} Fe atoms

C) 2.13 × 10 ^{26} Fe atoms

D) 4.69 × 10 ^{24} Fe atoms

E) 2.62 × 10^{25} Fe atoms

Watch Solution

How many xenon atoms are contained in 2.36 moles of xenon?

A) 1.87 × 10 ^{26} xenon atoms

B) 3.92 × 10 ^{24} xenon atoms

C) 1.42 × 10 ^{24} xenon atoms

D) 2.55 × 10 ^{23} xenon atoms

E) 7.91 × 10 ^{25} xenon atoms

Watch Solution

What is the mass (in kg) of 6.89 × 10 ^{25} molecules of CO2? The molar mass of CO2 is 44.01 g/mol.

A) 2.60 kg

B) 6.39 kg

C) 5.04 kg

D) 3.03 kg

E) 3.85 kg

Watch Solution

What mass (in kg) does 5.84 moles of titanium (Ti) have?

a. 0.352 kg

b. 0.122 kg

c. 0.820 kg

d. 0.280 kg

e. 0.632 kg

Watch Solution

A chemical reaction requires 6.00 moles of Fe(NO_{3})_{3}. What mass of iron(III) nitrate is needed?

A) 24.3 g

B) 875 g

C) 40.3 g

D) 1.45 x 10^{3} g

E) 515 g

Watch Solution

If the molar mass of a substance is 44.01 g/mol, what is the mass of 1.05 x 10 ^{24} molecules of the substance?

A) 76.7 g

B) 1.74 g

C) 4.62 x 10^{25} g

D) 4.19 x 10^{–23} g

E) 25.2 g

Watch Solution

If 4.05 x 10^{23} molecules of a substance have a mass of 86.2 g, what is the molar mass of the substance?

A) 128 g/mol

B) 3.49 x 10^{25} g/mol

C) 2.13 x 10^{22} g/mol

D) 4.70 x 10^{21} g/mol

E) 58.0 g/mol

Watch Solution

How many oxygen atoms are present in 1.50 mol of Zn(NO _{3})_{2}?

A) 4.50 atoms

B) 9.00 atoms

C) 9.03 ´ 10^{23} atoms

D) 5.42 ´ 10^{24} atoms

E) 1.49 ´ 10^{–23} atoms

Watch Solution

How many chloride ions are present in 0.100 mol of MgCl _{2}?

A) 0.200 Cl^{–} ions

B) 6.02 ´ 10^{22} Cl^{–} ions

C) 1.20 ´ 10^{23} Cl^{–} ions

D) 3.32 ´ 10^{–25} Cl^{–} ions

E) 3.01 ´ 10^{24} Cl^{–} ions

Watch Solution

How many formula units are in 0.25 mole of Na _{2}O?

A) 4.5 x 10^{23}

B) 0.75

C) 1.5 x 10^{23}

D) 4.2 x 10^{–25}

E) 0.25

Watch Solution

How many C atoms are in 5.50 g of C?

A. 5.01 x 10^{22} C atoms

B. 3.31 x 10^{24} C atoms

C. 6.02 x 10^{23} C atoms

D. 2.76 x 10^{23} C atoms

E. 5.50 x 10^{23} C atoms

Watch Solution

Determine the number of moles of aluminum in 96.7 g of Al.

A. 0.279 mol

B. 3.58 mol

C. 7.43 mol

D. 4.21 mol

E. 6.02 x 10^{23} mol

Watch Solution

How many moles of PBr_{3} are contained in 3.68 × 10^{25} bromine atoms?

A) 61.1 moles PBr_{3}

B) 20.4 moles PBr_{3}

C) 16.4 moles PBr_{3}

D) 183 moles PBr_{3}

E) 49.1 moles PBr_{3}

Watch Solution

What is the mass (in kg) of 6.89 × 10 ^{25} molecules of CO_{2}? The molar mass of CO_{2} is 44.01 g/mol.

A) 3.85 kg

B) 5.04 kg

C) 2.60 kg

D) 3.03 kg

E) 6.39 kg

Watch Solution

A 20.0 g sample of an element contains 4.95 x 10^{23} atoms. Identify the element.

A) Cr

B) O

C) Mg

D) Fe

Watch Solution

What is the molar mass of aspartic acid, C _{4}O_{4}H_{7}N?

A) 43.03 g/mol

B) 70.02 g/mol

C) 86.91 g/mol

D) 133.11 g/mol

E) 197.98 g/mol

Watch Solution

How many grams of Cr are found in 1.00 × 10 ^{2} g of K _{2}Cr_{2}O_{7}?

A) 33.8 g

B) 24.3 g

C) 12.2 g

D) 48.6 g

E) 35.4 g

Watch Solution

How many iron atoms are contained in 354 g of iron?

A) 9.50 × 10^{22} Fe atoms

B) 2.13 × 10^{26} Fe atoms

C) 3.82 × 10^{24} Fe atoms

D) 2.62 × 10^{25} Fe atoms

E) 4.69 × 10^{24} Fe atoms

Watch Solution

How many moles of Kr are contained in 398 mg of Kr?

A) 4.75 × 10 ^{-3} moles Kr

B) 1.19 × 10 ^{-4} moles Kr

C) 2.99 × 10 ^{-3} moles Kr

D) 33.4 moles Kr

E) 2.11 × 10 ^{-4} moles Kr

Watch Solution

How many moles of Ar are in 5.22 X 10^{22} atoms of this noble gas?

Watch Solution

How many Na atoms are there in 1.50 mol Na?

a.1.50

b. 9.03 X´10^{23 }

c. 3.00

d. 2.49 X´10^{-24}

e. 345

Watch Solution

What is the mass (grams) of 4.91 x 10^{21} Pt atoms?

1 mol Pt = 195.08 g = 6.022 x 10^{23} atoms

Watch Solution

How many atoms of calcium are in 4.008g of calcium metal?

Watch Solution

How many moles of manganese atoms are in 19.36 g of manganese metal?

Watch Solution

What is the mass (g) of silicon represented by 0.250 moles of elemental silicon?

Watch Solution

How many molecules of N_{2}O_{4} are in 76.3 g N_{2}O_{4}? The molar mass of N_{2}O_{4} is 92.02 g/mol.

a. 5.54 x 10^{25} N_{2}O_{4} molecules

b. 7.26 x 10^{23} N_{2}O_{4} molecules

c. 1.38 x 10^{24} N_{2}O_{4} molecules

d. 4.59 x 10^{25} N_{2}O_{4} molecules

e. 4.99 x 10^{23} N_{2}O_{4} molecules

Watch Solution

The ebola virus is structured like a long filament that ranges from 974 to 1086 nm in length. If length of a virus filament is found to be 1046 nm, what would the the length be in cm?

a. 1.046 x 10^{10} cm

b. 1.046 x 10 ^{-4} cm

c. 1.046 x 10^{14} cm

d. 1.046 x 10 ^{-8} cm

e. 1.046 x 10^{-3} cm

Watch Solution

Amavadin is a vanadium-containing compound found in three species of toxic mushrooms. The chemical formula for amavadin is VC_{12}H_{16}N_{2}O_{10} and has molar mass 398.94 g•mol^{-1}. If a mushroom contains 2.00 mg of amavadin, how many molecules are present?

a. 1.20 x 10^{23}

b. 4.80 x 10^{23}

c. 3.02 x 10^{21}

d. 3.02 x 10^{18}

Watch Solution

What mass (in kg) does 0.0822 moles of lead (Pb) have?

a. 0.397 kg

b. 17.0 kg

c. 2.52 kg

d. 0.0170 kg

e. 0.632 kg

Watch Solution

In the chemical reaction N_{2} + 3 Mg → Mg _{3}N_{2 }if you begin with 1.35 moles of Mg, how many moles of N_{2} are required to react all of the Mg?

A. 0.45

B. 1.01

C. 1.35

D. 1.80

E. 4.05

Watch Solution

The Freons are a class of compounds containing carbon, chlorine, and fluorine. While they have many valuable uses, they have been shown to be responsible for depletion of the ozone in the upper atmosphere. In 1991, two replacement compounds for Freons went into production: HFC-134a (CH_{2}FCF_{3}) and HCFC-124 (CHClFCF_{3}). Calculate the molar masses of these two compounds.

Watch Solution

If 2.50 grams of an unknown compound contains 6.25 x 10 ^{19} molecules, what is its molecular mass?

Watch Solution

Which of the following amounts have the ** most** molecules?

a) 15.0 g N_{2}

b) 15.0 g Br_{2}

c) 15.0 g O_{2}

d) 15.0 g l_{2}

Watch Solution

Which of the following amounts would contain the ** least** atoms?

a) 10.0 g Sr

b) 10.0 g Br

c) 10.0 g Mg

d) 10.0 g Li

Watch Solution

How many atoms of oxygen are there in 53.2 g Al _{2}(SO_{4})_{3}?

a. 9.36 x 10^{22}

b. 3.75 x 10^{23}

c. 1.12 x 10^{24}

d. 2.81 x 10^{23}

Watch Solution

A 7.36-g sample of copper is contaminated with an additional 0.51 g of zinc. Suppose an atomic mass measurement was performed on this sample. What would be the measured atomic mass?

Watch Solution

How many moles of aluminum do 5.8 X 10^{24} aluminum atoms represent?

Watch Solution

How many sulfur atoms are there in 3.8 mol of sulfur?

Watch Solution

The atomic mass of copper is 63.546 amu. Do any copper isotopes have a mass of 63.546 amu? Explain.

Watch Solution

In Section 2.9, it was stated that 1 mol of sand grains would cover the state of Texas to several feet. Estimate how many feet by assuming that the sand grains are roughly cube-shaped, each one with an edge length of 0.10 mm. Texas has a land area of 268,601 square miles.

Watch Solution

A 67.2 g sample of a gold and palladium alloy contains 2.49 x 10 ^{23} atoms. What is the composition (by mass) of the alloy?

Watch Solution

A pure titanium cube has an edge length of 2.78 in. How many titanium atoms does it contain? Titanium has a density of 4.50 g/ cm^{3}.

Watch Solution

The mass of an average blueberry is 0.75 g and the mass of an automobile is 2.0 X 10^{3} kg. Find the number of automobiles whose total mass is the same as 1.0 mol blueberries.

Watch Solution

Consider the stack of pennies in the previous problem. How much money (in dollars) would this represent? If this money were equally distributed among the world's population of 6.5 billion people, how much would each person receive? Would each person be a millionaire? Billionaire? Trillionaire?

Watch Solution

A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in km)? [For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth.]

Watch Solution

An α particle, ^{4}H^{2+}, has a mass of 4.00151 amu. Find the value of its charge-to-mass ratio in C/kg.

Watch Solution

The ratio of the mass of a nitrogen atom to the mass of an atom of ^{12}C is 7:6 and the ratio of the mass of nitrogen to oxygen in N_{2}O is 7:4. Find the mass of 1 mol of oxygen atoms.

Watch Solution

The ratio of oxygen to carbon by mass in carbon monoxide is 1.33:1.00. Find the formula of an oxide of carbon in which the ratio by mass of oxygen to carbon is 2.00:1.00.

Watch Solution

The ratio of sulfur to oxygen by mass in SO _{2 }is 1.0:1.0.

a. Find the ratio of sulfur to oxygen by mass in SO _{3}.

b. Find the ratio of sulfur to oxygen by mass in S _{2}O.

Watch Solution

A 7.83-g sample of HCN is found to contain 0.290 g of H and 4.06 g of N. Find the mass of carbon in a sample of HCN with a mass of 3.37 g.

Watch Solution

Using scanning tunneling microscopy, scientists at IBM wrote the initials of their company with 35 individual xenon atoms (as shown below). Calculate the total mass of these letters in grams.

Watch Solution

Calculate the average mass, in grams, of one platinum atom.

Watch Solution

How many helium atoms are there in a helium blimp containing 536 kg of helium?

Watch Solution

Calculate the mass, in kg, of each sample.

a. 7.55 x 10^{26} cadmium atoms

b. 8.15 x 10^{27} nickel atoms

c. 1.22 x 10^{27} manganese atoms

d. 5.48 x 10^{29} lithium atoms

Watch Solution

What is the mass of 4.91 x 10 ^{21} platinum atoms?

Watch Solution

What is the mass, in grams, of each elemental sample?

d. 1.3 mol W

Watch Solution

What is the mass, in grams, of each elemental sample?

c. 43.9 mol Xe

Watch Solution

What is the mass, in grams, of each elemental sample?

b. 0.0355 mol Ba

Watch Solution

What is the mass, in grams, of each elemental sample?

a. 2.3 x 10 ^{–3} mol Sb

Watch Solution

Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below:

Show that these masses are consistent with the law of multiple proportions.

Watch Solution

Upon decomposition, one sample of magnesium fluoride produced 1.65 kg of magnesium and 2.57 kg of fluorine. A second sample produced 1.32 kg of magnesium. How much fluorine (in grams) did the second sample produce?

Watch Solution

The mass ratio of sodium to fluorine in sodium fluoride is 1.21: 1. A sample of sodium fluoride produced 28.8 g of sodium upon decomposition. How much fluorine (in grams) was formed?

Watch Solution

Two samples of carbon tetrachloride were decomposed into their constituent elements. One sample produced 38.9 g of carbon and 448 g of chlorine, and the other sample produced 14.8 g of carbon and 134 g of chlorine. Are these results consistent with the law of definite proportions? Show why or why not.

Watch Solution

For each box, examine the blocks attached to the balances. Based on their positions and sizes, determine which block is more dense (the dark block or the lighter-colored block), or if the relative densities cannot be determined. (Think carefully about the information being shown.)

Watch Solution

Lead metal can be extracted from a mineral called galena, which contains 86.6% lead by mass. A particular ore contains 68.5% galena by mass. If the lead can be extracted with 92.5% efficiency, what mass of ore is required to make a lead sphere with a 5.00 em radius?

Watch Solution

Table salt contains 39.33 g of sodium per 100 g of sail. The U.S. Food and Drug Administration (FDA) recommends that adults consume less than 2.40 g of sodium per day. A particular snack mix contains 1.25 g of salt per 100 g of the mix. What mass of the snack mix can you consume and slill be within the FDA limit? (Assume three significant figures for 100 g.)

Watch Solution

The diameter of a hydrogen atom is 212 pm. Find the length in kilometers of a row of 6.02 X 10^{23} hydrogen atoms. The diameter of a ping pong ball is 4.0 cm. Find the length in kilometers of a row of 6.02 X 10^{23} ping pong balls.

Watch Solution

A thief uses a can of sand to replace a solid gold cylinder that sits on a weight-sensitive, alarmed pedestal. The can of sand and the gold cylinder have exactly the same dimensions (length = 22 cm and radius = 3.8 cm).

a. Calculate the mass of each cylinder (ignore the mass of the can itself). (density of gold = 19.3 g/cm^{3}, density of sand = 3.00 g/cm^{3})

b. Did the thief set off the alarm? Explain.

Watch Solution

The value of the Euro is currently $1.35 U.S. and the price of 1 liter of gasoline in France is 0.97 Euro. What is the price of 1 gallon of gasoline in U.S. dollars in France?

Watch Solution

The average U.S. farm occupies 435 acres. How many square miles is this? (1 acre = 43,560 ft^{2}, 1 mile = 5280 ft)

Watch Solution

How many moles of sodium ions (Na ^{+}) are in 56.0 g of sodium phosphate (Na _{3}PO_{4})?

A. 0.342 mol Na^{+}

B. 1.03 mol Na^{+}

C. 0.114 mol Na^{+}

D. 3.06 x 10^{3} mol Na^{+}

Watch Solution

A 2.000 g sample of an unknown metal, M, was completely burned in excess O _{2} to yield 0.02224 mol of the metal oxide, M_{2}O_{3}. What is the metal?

A. Y

B. Ca

C. Al

D. Sc

Watch Solution

The number of atoms in 9.0 g of aluminum is the same as the number of atoms in _____.

A. 8.1 g of magnesium

B. 9.0 g of magnesium

C. 12.1 g of magnesium

D. 18.0 g of magnesium

Watch Solution

What mass of carbon is present in 1.4 x 10 ^{20} molecules of sucrose (C_{12}H_{22}O_{11})?

a) 1.7 x 10^{21} g

b) 2.0 x 10^{22} g

c) 3.3 x 10 ^{-2} g

d) 2.8 x 10^{-3} g

Watch Solution

How many atoms are in 1.50 g of Al?

a) 0.0556

b) 18.0

c) 3.35 x 10^{22}

d) 2.44 x 10^{25}

Watch Solution

What mass of carbon is present in 0.500 mol of sucrose (C _{12}H_{22}O_{11})?

a) 60.0 g

b) 72.0 g

c) 90.0 g

d) 120.0 g

Watch Solution

What mass of KClO_{3} will produce 48.0 g of oxygen gas, O_{2}, if the decomposition of KClO_{3} is complete?

a) 61.3 g

b) 74.5 g

c) 122.5 g

d) 245.0 g

Watch Solution

A single molecule of a certain compound has a mass of 3.4 x 10 ^{–22} g. Which value comes closest to the mass of a mole of this compound?

a) 50 g•mol^{–1}

b) 100 g•mol^{–1}

c) 150 g•mol^{–1}

d) 200 g•mol^{–1}

Watch Solution

The number of atoms in 9.0 g of aluminum is the same as the number of atoms in

a) 8.1 g of magnesium.

b) 9.0 g of magnesium.

c) 12.1 g of magnesium.

d) 18.0 g of magnesium.

Watch Solution

A 3.41 x 10^{–6} g sample of a compound is known to contain 4.67 x 10 ^{16} molecules. This compound is

a) CO_{2}

b) CH_{4}

c) NH_{3}

d) H_{2}O

Watch Solution

A sample of a compound of xenon and fluorine contains molecules of a single type; XeF* _{n }*, where

a) 2

b) 3

c) 4

d) 6

Watch Solution

What mass of the compound CrO_{3} (M = 100.0) contains 4.5 x 10 ^{23} oxygen atoms?

a) 2.25 g

b) 12.0 g

c) 25.0 g

d) 75.0 g

Watch Solution

If the mass of 2.51 x 10 ^{-3} moles of compound A is 0.452 g, then what is the molar mass?

Watch Solution

How many sodium ions are contained in 99.6 mg of Na _{2}SO_{3} ?

a) 1.05 X 10^{21}

b) 1.52 X 10^{27}

c) 2.10 X 10^{21}

d) 9.52 X 10^{20}

Watch Solution

How many moles of C_{3}H_{8} contain 9.25 × 10^{24} molecules of C_{3}H_{8}?

A) 65.1 moles C_{3}H_{8}

B) 28.6 moles C_{3}H_{8}

C) 34.9 moles C_{3}H_{8}

D) 46.2 moles C_{3}H_{8}

E) 15.4 moles C_{3}H_{8}

Watch Solution

How many sodium ions are contained in 99.6 mg of Na _{2}SO_{3}? The molar mass of Na_{2}SO_{3} is 126.05 g/mol.

A) 1.52 × 10^{27} sodium ions

B) 4.76 × 10^{20} sodium ions

C) 2.10 × 10^{21} sodium ions

D) 1.05 × 10^{21} sodium ions

E) 9.52 × 10^{20} sodium ions

Watch Solution

How many atoms of oxygen are contained in 47.6 g of Al _{2}(CO_{3})_{3}? The molar mass of Al_{2}(CO_{3})_{3} is 233.99 g/mol.

A) 1.23 × 10^{23} O atoms

B) 2.96 × 10^{24} O atoms

C) 2.87 × 10^{25} O atoms

D) 1.10 × 10^{24} O atoms

E) 3.19 × 10^{24} O atoms

Watch Solution

How many C_{2}H_{4} molecules are contained in 45.8 mg of C _{2}H_{4}? The molar mass of C_{2}H_{4} is 28.05 g/mol.

A) 9.83 × 10^{20} C_{2}H_{4} molecules

B) 7.74 × 10^{26} C_{2}H_{4} molecules

C) 2.71× 10^{20} C_{2}H_{4} molecules

D) 3.69 × 10^{23} C_{2}H_{4} molecules

E) 4.69 × 10^{23} C_{2}H_{4} molecules

Watch Solution

How many N_{2}O_{4} molecules are contained in 76.3 g N _{2}O_{4}? The molar mass of N _{2}O_{4} is 92.02 g/mol.

A) 5.54 × 10^{25} N_{2}O_{4} molecules

B) 7.26 × 10^{23} N_{2}O_{4} molecules

C) 1.38 × 10^{24} N_{2}O_{4} molecules

D) 4.59 × 10^{25} N_{2}O_{4} molecules

E) 4.99 × 10^{23} N_{2}O_{4} molecules

Watch Solution

How many iron atoms are contained in 354 g of iron?

A) 2.62 × 10^{25} Fe atoms

B) 2.13 × 10^{26} Fe atoms

C) 4.69 × 10^{24} Fe atoms

D) 3.82 × 10^{24} Fe atoms

E) 9.50 × 10^{22} Fe atoms

Watch Solution

How many Li atoms are contained in 97.9 g of Li?

A) 5.90 × 10^{25} Li atoms

B) 7.09 × 10^{21} Li atoms

C) 8.49 × 10^{24} Li atoms

D) 4.27 × 10^{22} Li atoms

E) 4.18 × 10^{24} Li atoms

Watch Solution

How many argon atoms are contained in 7.66 x 10 ^{5} mol of argon?

A) 4.61 × 10^{29} Ar atoms

B) 1.84 × 10^{28} Ar atoms

C) 1.15 × 10^{28} Ar atoms

D) 7.86 × 10^{20} Ar atoms

E) 3.24 × 10^{26} Ar atoms

Watch Solution

How many cm^{3} are contained in 3.77 × 10^{4} mm^{3}?

A) 3.77 × 10^{4} cm^{3}

B) 3.77 × 10^{1} cm^{3}

C) 3.77 × 10^{-10} cm^{3}

D) 3.77 × 10^{20} cm^{3}

E) 3.77 × 10^{6} cm^{3}

Watch Solution

A 0.370 mol sample of a metal oxide (M _{2}O_{3}) weighs 55.4 g. How many grams of M are in the sample, and what element is represented by the symbol M?

a) 75.28 g/mol; Arsenic

b) 101.7 g; Ruthenium

c) 37.6 g; Vanadium

d) 17.8 g; Metalium

e) 41.3 g; Iron

Watch Solution

How many moles are in 26.7 grams of calcium nitrate?

Watch Solution

What mass of carbon is present in 0.500 mol of sucrose (C_{12}H_{22}O_{11})?

Molar mass: C_{12}H_{22}O_{11} = 342 g/mol

A. 60.0 g

B. 72.0 g

C. 90.0 g

D. 120 g

Watch Solution

A 1.000-g sample of a metal chloride, MCl _{2}, is dissolved in water and treated with excess aqueous silver nitrate. After drying, the silver chloride that formed weighed 1.286 g. Calculate the mass of M.

a) 222.8 g b) 76.00g c) 152.0 g d) 304.0 g e) none of these

Watch Solution

What is the atomic weight of an element, X, if 1.00g of X combines with 0.66 g of oxygen to form a compound XO_{3}?

A. 24

B. 67

C. 73

D. 100

E. 146

Watch Solution

What is A, if 64.0 g of A combines exactly with 142 g of Cl to give the compound ACl _{2}?

A. Br

B. Mg

C. Ca

D. S

E. Ba

Watch Solution

What is the mass of one molecule of C_{8}H_{18} (octane) in grams?

A. 114

B. 1.9 x 10^{-22}

C. 26

D. 6.9 x 10^{-21}

E. 3.8 x 10^{-22}

Watch Solution

A compound has a formula of Y_{2}O_{5}. If 2.8 g of Y combines with 8.0 g of oxygen, what is the atomic weight of Y?

A. 10

B. 12

C. 14

D. 16

E. 18

Watch Solution

Which of the following contains most hydrogen atoms in one gram of sample?

A. HClO_{4}

B. HClO_{3}

C. HClO_{2}

D. HClO

E. HCl

Watch Solution

Which contains the largest number of carbon atoms?

A. 0.10 mol of carbon atoms

B. 1.2 g carbon

C. 0.10 mol of CH_{4}

D. 1.6 g of CH_{4}

E. All are the same

Watch Solution

How many moles are in 25 mg of O _{2}? (Atomic mass of O = 16.00 g/mol)

A) 7.8 ×10^{−4}

B) 1.6 ×10^{−3 }

C) 0.40

D) 0.80

E) 800

Watch Solution

For a 90.0 g sample of glucose (C_{6}H_{12}O_{6)} and a 171.1 g sample of sucrose (C_{12}H_{22}O_{11}), which statement is true?

a. The sample of glucose has more moles than the sample of sucrose.

b. The sample of sucrose has more moles than the sample of glucose.

c. The samples have the same number of moles.

d. 1 mol of glucose has greater molecular mass than 1 mol of sucrose.

e. 1 mol of glucose has more C atoms in comparison to 1 mol of sucrose.

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We have a 1.3 x 10^{22} lead atoms and the same number of gold atoms. Which statement is true regarding the mass of these samples?

a. The mass of both of the samples is the same

b. The mass of the lead sample is greater than the mass of the gold sample.

c. The mass of the gold sample is greater than the mass of the lead sample.

d. The mass of the gold sample is 4.5 g.

e. The mass of the lead sample is 4.3 g.

Watch Solution

The definition of the mole gives the relationship between:

a. mass and the atomic number.

b. mass and number of atoms.

c. mass and weight.

d. the masses of the different isotopes of an atom.

e. the isotopes of an atom and the number of atoms.

Watch Solution

Which statement below is true?

a. The number of Ni atoms in 100 moles of Ni (s) is the same as the number of Ni atoms in 100 moles of nickel (II) chloride, NiCl_{2}.

b. One moles of NH _{3} weighs more than one mole of H _{2}O.

c. There are equal numbers of nitrogen atoms in one mole of NH _{3} and one mole of N _{2}.

d. The number of Cu atoms in 100 grams of Cu (s) is the same as the number of Cu atoms in 100 grams of copper (II) oxide, CuO.

e. There are more hydrogen atoms in 2 moles of NH _{3} than in 2 moles of CH _{4}.

Watch Solution

One molecule of a compound weighs 2.03 x 10 ^{-22} grams. Calculate the molar mass of this molecule.

a. 3.37 x 10^{-46} g/mol

b. 3.36 x 10^{-23} g/mol

c. 1.23 x 10^{-21} g/mol

d. 1.22 x 10 ^{2} g/mol

e. 1.21 x 10^{24} g/mol

Watch Solution

What is the molar mass of calcium phosphate, Ca _{3}(PO_{4})_{2}?

a. 87.05 g/mol

b. 215.21 g/mol

c. 278.18 g/mol

d. 279.21 g/mol

e. 310.18 g/mol

Watch Solution

How many moles of methanol are present in a 150.0 gram sample of methanol, CH_{3}OH?

a. 7.776 x 10 ^{-24 }moles

b. 4.681 moles

c. 5.172 moles

d. 4806 moles

e. 2.818 x 10 ^{24} moles

Watch Solution

What mass (in kg) does 5.84 moles of Titanium (Ti) have?

a. 0.352 kg

b. 0.122 kg

c. 0.820 kg

d. 0.280 kg

e. 0.632 kg

Watch Solution

If 2.50 grams of an unknown compound contains 6.25 x 10^{19} molecules, what is its molecular mass?

Watch Solution

Which of the following equals the number of hydrogen atoms in 40 grams of methane?

a. 1.5 x 10 ^{24}

b. 2.4 x 10 ^{24}

c. 6.0 x 10 ^{24}

d. 6.022 x 10 ^{23}

Watch Solution

What is the mass of one molecule of C _{8}H_{18} (octane) in grams?

A. 114

B. 1.9 x 10^{-22 }

C. 26

D. 6.9 x 10^{-21 }

E. 3.8 x 10^{-22}

Watch Solution

A single atom of a certain element has a mass of 3.352 x 10 ^{-23 }g. The element is

a. Ne

b. Co

c. Al

d. Br

e. Ti

Watch Solution

What is the mass of 1.3 x 10 ^{13} moles of N_{2 }in pg?

a. 3.64 x 10^{14}

b. 1.82 x 10^{14}

c. 1.82 x 10^{26}

d. 3.64 x 10^{26}

e. none of the given answers is even close to being correct

Watch Solution

What is the weight of O in 742.0 g of citronella oil that has the chemical formula C_{10}H_{18}O?

a. 19.31

b. 18.52

c. 77.10

d. 115.5

e. 231.3

Watch Solution

How many oxygen atoms are in a 125 mg sample of aspirin? The molar mass of aspirin is 180.15 g/mol and its molecular formula is C_{9}H_{8}O_{4}.

a) 4.18 × 10^{23 }

b) 4.18 × 10^{20 }

c) 1.67 × 10^{21}

d) 1.36 × 10^{25}

e) 8.68 × 10^{23}

Watch Solution

A piece of metal was placed in a beaker, heated, and reacted with oxygen, thereby becoming a metal oxide. During this process, depending on reaction conditions, the metal’s oxidation state could become either M^{2+} or M^{3+}. Consider the mass of the metal oxide.

a) The mass of the metal oxide is the same as the mass of the initial metal

b) The mass of the metal oxide is greatest if the metal becomes M ^{3+}

c) The mass of the metal oxide is greatest if the metal becomes M ^{2+}

d) The mass of the metal oxide is greatest if O _{2}(g) is the limiting reactant.

Watch Solution

How many Cl^{–} ions are there in 15.6 g of MgCl _{2}?

Watch Solution

How many Cl atoms are there in 27.3 grams of magnesium chloride?

Watch Solution

Identify the correct statement regarding the mole.

a) A mole of oxygen gas contains 6.02 x 10 ^{23} atoms.

b) A mole of chlorine gas contains 2 x 6.02 x 10 ^{23} molecules.

c) A mole of carbon dioxide contains two moles of oxygen atoms.

d) A mole of ammonia gas (NH _{3}) has a mass of 34.0 g.

e) A mole consists of the number of particles in exactly 12 g of naturally occurring carbon.

Watch Solution

A 1.000-g sample of a metal chloride, MCl _{2}, is dissolved in water and treated with excess aqueous silver nitrate. After drying, the silver chloride that formed weighed 1.286 g. Calculate the atomic mass of M.

a) 222.8 g

b) 76.00 g

c) 152.0 g

d) 304.0 g

e) none of these

Watch Solution

How many Cl atoms are there in 27.3 grams of magnesium chloride?

Watch Solution