Chemistry Chemistry Practice Problems Solutions Library

Atomic Mass Solutions Library

Access 152 Atomic Mass video and text solutions to help you complete your homework. Need to revisit the concept? Watch our Atomic Mass learn videos.

Browse Solutions

152 solutions

Atomic Mass

Q. Part A. Which of the following water molecules exists in the greatest abundance? There are three naturally occurring isotopes of hydrogen:protium (...

Solved • Jul 1, 2020

Atomic Mass

Q. In the PhET simulation, click on the Mixtures tab. Select Mg from the periodic table. Drag the colored spheres representing the different isotopes ...

Solved • Jul 1, 2020

Atomic Mass

Q. Click on the Mixtures tab in the PhET simulation. Click on yellow cells in the periodic table shown in the upper right to select an element. You ca...

Solved • Jul 1, 2020

Atomic Mass

Q. What is the relative atomic mass of the element that consists of the following isotopes in the indicated natural abundances?Express your answer to ...

Solved • Jun 30, 2020

Atomic Mass

Q. What is the relative atomic mass of a hypothetical element that consists of the following isotopes in the indicated natural abundances?Express your...

Solved • Jun 30, 2020

Atomic Mass

Q. The two isotopes of chlorine are 3517Cl and 3717Cl. Which isotope is the most abundant?Atomic mass Since the number of neutrons varies in the perio...

Solved • Jun 30, 2020

Atomic Mass

Q. What is the identity of element X from Part B? Express your answer as a chemical symbol.Atomic mass Since the number of neutrons varies in the peri...

Solved • Jun 30, 2020

Atomic Mass

Q. A certain element X has four isotopes. 0.5600% of X has a mass of 83.91343 amu. 9.860% of X has a mass of 85.90927 amu. 7.000% of X has a mass of 8...

Solved • Jun 30, 2020

Atomic Mass

Q. What are the masses of the four different BrCl molecules? Express the masses in atomic mass units using six significant figures, in decreasing nume...

Solved • Jun 30, 2020

Atomic Mass

Q. Magnesium has three naturally occurring isotopes Mg-24, Mg-25, and Mg-26). The atomic mass and natural abundance of Mg-24 are 23.9850 amu and 79 %....

Solved • May 1, 2020

Atomic Mass

Q. A certain element X has four isotopes. • 5.845% of X has a mass of 53.93961 amu. • 91.75% of X has a mass of 55.93494 amu. • 2.123% of X has a mass...

Solved • Apr 28, 2020

Atomic Mass

Q. The naturally occurring isotopes of element X consists of the isotopes 63X, and 65X. The atomic mass of 63X is 62.9396 amu with a percent abundance...

Solved • Nov 28, 2019

Atomic Mass

Q. Rubidium has two isotopes, rubidium-85 and rubidium-87. The atomic weight of rubidium is 85.4678 amu. If the atomic weight of rubidium-85 is 84.911...

Solved • Nov 25, 2019

Atomic Mass

Q. An unknown element with atomic weight 125.8 amu has two isotopes. One isotope has an abundance of 51.97% at 125.6 amu. Find the mass of the second ...

Solved • Oct 3, 2019

Atomic Mass

Q. Three isotopes of A (Isotope 1: 85.91 amu, 35.12%, Isotope 2: 86.91 amu, abundance 7%, Isotope 3: 87.91 amu) would have the atomic mass of what?

Solved • Sep 18, 2019

Atomic Mass

Q. There are two isotopes of Y, 50Y (mass 49.972 amu, abundance 24.93%), 52Y (mass 51.966 amu). The atomic mass of Y in amu is what?

Solved • Sep 18, 2019

Atomic Mass

Q. Pretend that a new element named Szulczewskium (Sz) has been discovered. It is found to have three naturally occurring isotopes. Use the informatio...

Solved • Sep 17, 2019

Atomic Mass

Q. Pretend that a new element with an atomic weight of 342.38 amu was recently discovered. This element has two isotopes, the lighter of which has a m...

Solved • Sep 12, 2019

Atomic Mass

Q. Gallium consists of 2 isotopes. One of those isotopes is Ga-71 with a mass of 70.92 amu with an abundance of 39.892%. What is the mass number of th...

Solved • Aug 7, 2019

Atomic Mass

Q. What is the atomic mass of neon?

Solved • Aug 7, 2019

Atomic Mass

Q. What is the average atomic mass of silicon? Given the following data, calculate the average atomic mass of silicon.isotope = Si-28amu =27.9769abund...

Solved • Aug 7, 2019

Atomic Mass

Q. Chorline exists mainly as two isotopes 35Cl and 37Cl,a) Which is more abundant?b) How do you know?c) Compute the percentage of chlorine that is the...

Solved • Aug 5, 2019

Atomic Mass

Q. The two naturally occurring isotopes of bromine are 81Br (80.916 amu, 49.31%) and 79Br (78.918 amu, 50.69%). The two naturally occurring isotopes o...

Solved • Aug 5, 2019

Atomic Mass

Q. Which of the following water molecules exists in the greatest abundance?a. D217Ob. H218Oc. T218Od. H216Oe. D216Of. T217O

Solved • Jul 10, 2019

Atomic Mass

Q. Naturally occurring boron consists of two isotopes: 10B (19.9%) with an isotopic mass of 10.0129 amu and 11B (80.1%) with an isotopic mass of 11.00...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring silver consists of two isotopes: 107Ag (51.84%) with an isotopic mass of 106.9051 amu and 109Ag (48.16%) with an isotopic mass ...

Solved • Oct 25, 2018

Atomic Mass

Q. Magnesium has three naturally occurring isotopes: 24 Mg (23.985 amu) with 78.99% abundance, 25 Mg (24.986 amu) with 10.00% abundance, and a third w...

Solved • Oct 25, 2018

Atomic Mass

Q. Copper metal has two naturally occurring isotopes: copper-63 (69.15%; isotopic mass = 62.93) and copper-65 (30.85%; isotopic mass = 64.93). Calcula...

Solved • Oct 25, 2018

Atomic Mass

Q. Gallium has two naturally occurring isotopes: gallium-69 (isotopic mass = 68.926 amu) and gallium-71 (isotopic mass = 70.925 amu). The atomic weigh...

Solved • Oct 25, 2018

Atomic Mass

Q. The nucleus of 6Li is a powerful absorber of neutrons. It exists in the naturally occurring metal to the extent of 7.5%. In the era of nuclear dete...

Solved • Oct 25, 2018

Atomic Mass

Q. The element lead (Pb) consists of four naturally occurring isotopes with atomic masses 203.97302, 205.97444, 206.97587, and 207.97663 amu. The rela...

Solved • Oct 25, 2018

Atomic Mass

Q. Gallium (Ga) consists of two naturally occurring isotopes with masses of 68.926 and 70.925 amu.The average atomic mass of Ga is 69.72 amu. Calculat...

Solved • Oct 25, 2018

Atomic Mass

Q. Using a suitable reference such as the CRC Handbook of Chemistry and Physics  or http://www.webelements.com, look up the following information for ...

Solved • Oct 25, 2018

Atomic Mass

Q. What isotope is used as the standard in establishing the atomic mass scale?

Solved • Oct 25, 2018

Atomic Mass

Q. The atomic weight of boron is reported as 10.81, yet no atom of boron has the mass of 10.81 amu. Explain.

Solved • Oct 25, 2018

Atomic Mass

Q. What is the mass in amu of a carbon-12 atom?

Solved • Oct 25, 2018

Atomic Mass

Q. Complete the sentence to explain why the atomic weight of carbon is reported as 12.011 in the table of elements and the periodic table in the front...

Solved • Oct 25, 2018

Atomic Mass

Q. Only two isotopes of copper occur naturally, 63 Cu (atomic mass = 62.9296  amu; abundance 69.17 %) and 65 Cu (atomic mass = 64.9278  amu; abundance...

Solved • Oct 25, 2018

Atomic Mass

Q. Rubidium has two naturally occurring isotopes, rubidium-85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium-87 (atomic mass = 86.9092 a...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring magnesium has the following isotopic abundances:IsotopeAbundance Atomic mass (amu) 24 Mg78.99%23.9850425 Mg10.00%24.9858426 Mg1...

Solved • Oct 25, 2018

Atomic Mass

Q. The following diagram is a representation of 20 atoms of a fictitious element, which we will call nevadium (Nv). The red spheres are 293Nv, and the...

Solved • Oct 25, 2018

Atomic Mass

Q. The following diagram is a representation of 20 atoms of a fictitious element, which we will call nevadium (Nv). The red spheres are 293Nv, and the...

Solved • Oct 25, 2018

Atomic Mass

Q. A particular atom of chromium has a mass of 52.94 amu, whereas the atomic weight of chromium is 51.99 amu. Explain the difference in the two masses.

Solved • Oct 25, 2018

Atomic Mass

Q. In a naturally occurring sample, 19.8% of boron atoms have five neutrons and 80.2% have six neutrons.What is the mass number of a boron atom contai...

Solved • Oct 25, 2018

Atomic Mass

Q. In a naturally occurring sample, 19.8% of boron atoms have five neutrons and 80.2% have six neutrons.What is the average mass of the atoms in the d...

Solved • Oct 25, 2018

Atomic Mass

Q. In a naturally occurring sample, 19.8% of boron atoms have five neutrons and 80.2% have six neutrons.What is the atomic mass of boron?

Solved • Oct 25, 2018

Atomic Mass

Q. Magnesium has three naturally occurring isotopes with masses of 23.99 amu, 24.99 amu, and 25.98 amu and natural abundances of 78.99 %, 10.00 %, and...

Solved • Oct 25, 2018

Atomic Mass

Q. Gallium has two naturally occurring isotopes: Ga-69 with a mass of 68.9256 amu and a natural abundance of 60.11 %, and Ga-71. Use the atomic mass o...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring iodine has an atomic mass of 126.9045 amu. A 12.3849-g sample of iodine is accidentally contaminated with 1.00070 g of 129I, a ...

Solved • Oct 25, 2018

Atomic Mass

Q. Bromine has two naturally occurring isotopes (Br-79 and Br-81) and has an atomic mass of 79.904 amu. The mass of Br-81 is 80.9163 amu, and its natu...

Solved • Oct 25, 2018

Atomic Mass

Q. Silicon has three naturally occurring isotopes (Si-28, Si-29, and Si-30). Masses and natural abundances for two isotopes are listed here.IsotopeMas...

Solved • Oct 25, 2018

Atomic Mass

Q. Silicon has three naturally occurring isotopes (Si-28, Si-29, and Si-30). Masses and natural abundances for two isotopes are listed here.IsotopeMas...

Solved • Oct 25, 2018

Atomic Mass

Q. Lithium has two naturally occurring isotopes: Li-6 (natural abundance 7.5%) and Li-7 (natural abundance 92.5%).How many Li-6 atoms would be present...

Solved • Oct 25, 2018

Atomic Mass

Q. Gallium has two naturally occurring isotopes with the following masses and natural abundances:Isotope Mass (amu) Abundance (%)Ga-6968.9255860.108Ga...

Solved • Oct 25, 2018

Atomic Mass

Q. Why is the mass corresponding to a mole of one element different from the mass corresponding to a mole of another element?

Solved • Oct 25, 2018

Atomic Mass

Q. A naturally occurring sample of an element contains only two isotopes. The first isotope has a mass of 68.9255 amu and a natural abundance of 60.11...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring magnesium has an atomic mass of 24.312 and consists of three isotopes. The major isotope is 24Mg, natural abundance 78.99%, rel...

Solved • Oct 25, 2018

Atomic Mass

Q. Lithium has two naturally occurring isotopes: Li-6 (natural abundance 7.5%; mass 6.0151 amu) and Li-7 (natural abundance 92.5%; mass 7.0160 amu).Wi...

Solved • Oct 25, 2018

Atomic Mass

Q. Silver is composed of two naturally occurring isotopes: Ag-107 (51.839%) and Ag-109. The ratio of the masses of the two isotopes is 1.0187.What is ...

Solved • Oct 25, 2018

Atomic Mass

Q. Below is a representation of 50 atoms of a fictitious element called westmontium (Wt). The red spheres represent Wt-296, the blue spheres Wt-297, a...

Solved • Oct 25, 2018

Atomic Mass

Q. Below is a representation of 50 atoms of a fictitious element called westmontium (Wt). The red spheres represent Wt-296, the blue spheres Wt-297, a...

Solved • Oct 25, 2018

Atomic Mass

Q. Below is a representation of 50 atoms of a fictitious element called westmontium (Wt). The red spheres represent Wt-296, the blue spheres Wt-297, a...

Solved • Oct 25, 2018

Atomic Mass

Q. Below is a representation of 50 atoms of a fictitious element called westmontium (Wt). The red spheres represent Wt-296, the blue spheres Wt-297, a...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring cobalt consists of only one isotope, 59Co, whose relative atomic mass is 58.9332. A synthetic radioactive isotope of cobalt, 60...

Solved • Oct 25, 2018

Atomic Mass

Q. A 6.18 g sample of copper is contaminated with an additional 0.71 g of zinc. Suppose an atomic mass measurement was performed on this sample.What w...

Solved • Oct 25, 2018

Atomic Mass

Q. Boron has only two naturally occurring isotopes. The mass of boron-10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu .Use the atomic mass...

Solved • Oct 25, 2018

Atomic Mass

Q. Boron has only two naturally occurring isotopes. The mass of boron-10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu .Use the atomic mass...

Solved • Oct 25, 2018

Atomic Mass

Q. Lithium has only two naturally occurring isotopes. The mass of lithium-6 is 6.01512 amu and the mass of lithium-7 is 7.01601 amu.Use the atomic mas...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring chlorine is composed of two isotopes: 75.76 % Cl-35 (mass of 34.9688 amu) and 24.24 % Cl-37(mass of 36.9659 amu). Naturally occ...

Solved • Oct 25, 2018

Atomic Mass

Q. Naturally occurring chlorine is composed of two isotopes: 75.76 % Cl-35 (mass of 34.9688 amu) and 24.24 % Cl-37(mass of 36.9659 amu). Naturally occ...

Solved • Oct 25, 2018

Atomic Mass

Q. You may want to reference (Pages 66 - 69) Section 2.8 while completing this problem.An element has four naturally occurring isotopes with the masse...

Solved • Oct 25, 2018

Atomic Mass

Q. Magnesium has three naturally occurring isotopes with the following masses and natural abundances:Isotope Mass (amu)  Abundance (%)Mg-2423.985078.9...

Solved • Oct 25, 2018

Atomic Mass

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

Solved • Oct 25, 2018

Atomic Mass

Q. An element has two naturally occurring isotopes. Isotope 1 has a mass of 120.9038 amu and a relative abundance of 57.4%, and isotope 2 has a mass o...

Solved • Oct 25, 2018

Atomic Mass

Q. An element has two naturally occurring isotopes. Isotope 1 has a mass of 120.9038 amu and a relative abundance of 57.4%, and isotope 2 has a mass o...

Solved • Oct 25, 2018

Atomic Mass

Q. An element has four naturally occurring isotopes with the masses and natural abundances given here.IsotopeMass (amu)Abundance (%)1135.907140.190021...

Solved • Oct 25, 2018

Atomic Mass

Q. What is atomic mass?

Solved • Oct 25, 2018

Atomic Mass

Q. How is it computed?Atomic Mass

Solved • Oct 25, 2018

Atomic Mass

Q. What is percent natural abundance?

Solved • Oct 25, 2018

Atomic Mass

Q. Carbon has two naturally occurring isotopes: C-12 (natural abundance is 98.93%) and C-13 (natural abundance is 1.07%).How many C-13 atoms are prese...

Solved • Oct 25, 2018

Atomic Mass

Q. Carbon has two naturally occurring isotopes: C-12 (natural abundance is 98.93%; mass is 12.0000 amu) and C-13 (natural abundance is 1.07%; mass is ...

Solved • Oct 25, 2018

Atomic Mass

Q. Variations in average atomic mass may be observed for elements obtained from different sources. Lithium provides an example of this. The isotopic c...

Solved • Oct 16, 2018

Atomic Mass

Q. Antimony has many uses, for example, in infrared devices and as part of an alloy in lead storage batteries. The element has two naturally occurring...

Solved • Oct 13, 2018

Atomic Mass

Q. Chlorine has two naturally occurring isotopes, 35Cl (isotopic mass = 34.9689 amu) and 37Cl (isotopic mass = 36.9659 amu). If chlorine has an atomic...

Solved • Oct 12, 2018

Atomic Mass

Q. There are two naturally occurring isotopes of rubidium. 85Rb has a mass of 84.9118 amu. 87Rb has a mass of 86.9092 amu. Determine the abundance of ...

Solved • Sep 27, 2018

Atomic Mass

Q. On another planet, the isotopes of titanium have the following natural abundances. What is the average atomic mass of titanium on that planet? 

Solved • Sep 26, 2018

Atomic Mass

Q. Suppose that a fictitious element, X, has two isotopes:  50X (59.015 amu) and 82X (62.011 amu). The lighter isotope has an abundance of 73.7%. Calc...

Solved • Sep 19, 2018

Atomic Mass

Q. Enter your answer in the provided box.Element X has two naturally occurring isotopes, 65X (isotopic mass 64.7079 amu, abundance 57.16%) and 67X (is...

Solved • Sep 12, 2018

Atomic Mass

Q. On a mission to a newly discovered planet, an astronaut finds gallium abundances of 61.29 % for 69Ga and 39.71 % for 71Ga. What s the atomic mass o...

Solved • Sep 11, 2018

Atomic Mass

Q. Part BThe astronaut then measures the abundance of magnesium on the new planet, obtaining the following result:What is the atomic mass of magnesium...

Solved • Sep 11, 2018

Atomic Mass

Q. On another planet, the isotopes of titanium have the following natural abundances. What is the average atomic mass of titanium on that planet?

Solved • Sep 11, 2018

Atomic Mass

Q. Gallium has two naturally occurring isotopes with the following masses and natural abundances: Part ACalculate the atomic mass of gallium. Express ...

Solved • Aug 28, 2018

Atomic Mass

Q. The element gallium has an atomic weight of 69.7 and consists of two stable isotopes gallium -69 and gallium -71. The isotope gallium -69 has a mas...

Solved • Aug 14, 2018

Atomic Mass

Q. Element A has two isotopes. The first isotope is present 5.15% of the time and has a mass of 243.39. The second isotope has a mass of 1845. Calcula...

Solved • Jul 4, 2018

Atomic Mass

Q. Strontium (Sr) has four naturally occurring isotopes. The percent abundance and atomic mass of each isotope is given below. (a) Calculate the avera...

Solved • Jul 3, 2018

Atomic Mass

Q. There are two stable isotopes of bromine. Their masses are 78.9183 and 80.9163 amu. If the average atomic mass of bromine is 79.9091 amu, what is t...

Solved • Jun 25, 2018

Atomic Mass

Q. Boron, lithium, nitrogen, and neon each have two stable isotopes. In which of the following pairs of isotopes is the heavier isotope more abundant?...

Solved • Jun 25, 2018

Atomic Mass

Q. The element bromine has an atomic weight of 79.9 and consists of two stable isotopes bromine-79 and bromine-81. The isotope bromine-79 has a mass o...

Solved • Jun 19, 2018

Atomic Mass

Q. Naturally occurring magnesium contains three isotopes, 24Mg, 25Mg, and 26Mg. The exact isotopic molar masses of each and their relative abundances ...

Solved • May 4, 2018

Atomic Mass

Q. Calculate the atomic mass of element "X", if it has 2 naturally occurring isotopes with the following masses and natural abundances:X-45           ...

Solved • Apr 2, 2018