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Assume you have a highly magnified view of a solution of HCl that allows you to “see” the HCl. Draw this magnified view. If you dropped in a piece of magnesium, the magnesium would disappear and hydrogen gas would be released. Represent this change using symbols for the elements, and write out the balanced equation.

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A sample of LSD (D-lysergic acid diethylamide, C24H30N3O) is added to some table salt (sodium chloride) to form a mixture. Given that a 1.00-g sample of the mixture undergoes combustion to produce 1.20 g of CO2, what is the mass percentage of LSD in the mixture?

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A 0.755-g sample of hydrated copper(II) sulfate CuSO4 • xH2O was heated carefully until it had changed completely to anhydrous copper(II) sulfate (CuSO4) with a mass of 0.483 g. Determine the value of x. [This number is called the number of waters of hydration of copper(II) sulfate. It specifies the number of water molecules per formula unit of CuSO4 in the hydrated crystal.]

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The empirical formula of styrene is CH; the molar mass of styrene is 104.14 g/mol. What number of H atoms are present in a 2.00-g sample of styrene?

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Some bismuth tablets, a medication used to treat upset stomachs, contain 262 mg of bismuth subsalicylate, C7H5BiO4, per tablet. Assuming two tablets are digested, calculate the mass of bismuth consumed.

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Many cereals are made with high moisture content so that the cereal can be formed into various shapes before it is dried. A cereal product containing 58% H2O by mass is produced at the rate of 1000 kg/hr. 

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A given sample of a xenon fluoride compound contains molecules of the type XeFn, where n is some whole number. Given that 9.03 x 1020 molecules of XeFn weighs 0.368 g, determine the value for n in the formula.

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Bornite (Cu3FeS3) is a copper ore used in the production of copper. When heated, the following reaction occurs:

2Cu3FeS3(s) + 7O2(g) → 6Cu(s) + 2FeO(s) + 6SO2(g)

If 2.50 metric tons of bornite is reacted with excess O 2 and the process has an 86.3% yield of copper, what mass of copper is produced?

 

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DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:

     2C 6H5Cl      +    C 2HOCl    →    C14H9Cl5    +   H2O

chlorobenzene         chloral                   DDT 

In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral.

d. If the actual yield of DDT is 200.0 g, what is the percent yield?

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DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:

     2C 6H5Cl      +    C 2HOCl    →    C14H9Cl5    +   H2O

chlorobenzene         chloral                   DDT 

In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral.

c. What mass of the excess reactant is left over?

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DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:

     2C 6H5Cl      +    C 2HOCl    →    C14H9Cl5    +   H2O

chlorobenzene         chloral                   DDT 

In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral.

b. Which reactant is limiting? Which is in excess?

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DDT, an insecticide harmful to fish, birds, and humans, is produced by the following reaction:

     2C 6H5Cl      +    C 2HOCl    →    C14H9Cl5    +   H2O

chlorobenzene         chloral                   DDT 

In a government lab, 1142 g of chlorobenzene is reacted with 485 g of chloral.
a. What mass of DDT is formed?

 

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Hydrogen peroxide is used as a cleaning agent in the treatment of cuts and abrasions for several reasons. It is an oxidizing agent that can directly kill many microorganisms; it decomposes upon contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams upon contact with blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxide can be prepared by the action of an acid on an alkaline earth metal peroxide, such as barium peroxide:

BaO2(s) + 2HCl(aq) → H2O2(aq) + BaCl2(aq)

What mass of hydrogen peroxide should result when 1.50 g of barium peroxide is treated with 25.0 mL of hydrochloric acid solution containing 0.0272 g of HCl per mL? What mass of which reagent is left unreacted?

 

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Coke is an impure form of carbon that is often used in the industrial production of metals from their oxides. If a sample of coke is 95% carbon by mass, determine the mass of coke needed to react completely with 1.0 ton of copper(II) oxide.

2CuO(s) + C(s) → 2Cu(s) + CO2(g)

 

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Phosphorus can be prepared from calcium phosphate by the following reaction:

2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) → 6CaSiO3(s) + P4(s) + 10CO(g)

Phosphorite is a mineral that contains Ca 3(PO4)2 plus other non-phosphorus-containing compounds. What is the maximum amount of P4 that can be produced from 1.0 kg of phosphorite if the phorphorite sample is 75% Ca3(PO4)2 by mass? Assume an excess of the other reactants.

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Bacterial digestion is an economical method of sewage treatment. The reaction below is an intermediate step in the conversion of the nitrogen in organic compounds into nitrate ions. What mass of bacterial tissue is produced in a treatment plant for every 1.0 x 104 kg of wastewater containing 3.0% NH4+ ions by mass? Assume that 95% of the ammonium ions are consumed by the bacteria.

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One of relatively few reactions that takes place directly between two solids at room temperature is

Ba(OH)2 • 8H2O(s) + NH4SCN(s) → Ba(SCN)2(s) + H2O(l) + NH3(g)

In this equation, the • 8H2O in Ba(OH) 2 • 8H2O indicates the presence of eight water molecules. This compound is called barium hydroxide octahydrate.

b. What mass of ammonium thiocyanate (NH 4SCN) must be used if it is to react completely with 6.5 g barium hydroxide octahydrate?

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One of relatively few reactions that takes place directly between two solids at room temperature is

Ba(OH)2 • 8H2O(s) + NH4SCN(s) → Ba(SCN)2(s) + H2O(l) + NH3(g)

In this equation, the • 8H2O in Ba(OH) 2 • 8H2O indicates the presence of eight water molecules. This compound is called barium hydroxide octahydrate.

a. Balance the equation.

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The reaction between potassium chlorate and red phosphorus takes place when you strike a match on a matchbox. If you were to react 52.9 g of potassium chlorate (KClO3) with excess red phosphorus, what mass of tetraphosphorus decaoxide (P4O10) would be produced?

KClO3(s) + P4(s) → P4O10(s) + KCl(s) (unbalanced)

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Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel rocket motors. The reaction is

Fe2O3(s) + 2Al(s) → 2Fe(l) + Al2O3(s)

What masses of iron(III) oxide and aluminum must be used to produce 15.0 g iron? What is the maximum mass of aluminum oxide that could be produced?

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Balance each of the following chemical equations.

g. FeCO3(s) + H2CO3(aq) → Fe(HCO3)2(aq)

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Balance each of the following chemical equations.

f. MoS2(s) + O2(g) → MoO3(s) + SO2(g)

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Balance each of the following chemical equations.

e. CaO(s) + C(s) → CaC2(s) + CO2(g)

 

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Balance each of the following chemical equations.

d. PCl5(l) + H2O(l) → H3PO4(aq) + HCl(g)

 

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Balance each of the following chemical equations.

c. NH3(g) + O2(g) → NO(g) + H2O(g)

 

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