Moles CalcuationsIII

1. Zinc iodide, can be prepared by the direct combination of elements. A chemist determines that
0.0654g can be produced in a double replacement reaction.
a.) How many grams of zinc iodide is this?
b.) How many atoms of zinc were needed?
c.) How many grams of iodine were produced in the reaction?
2. Lead (II) chromate is a yellow paint pigment prepared by a precipitation reaction. In a
preparation, 45.6 g of lead (II) chromate is obtained. How many moles were produced?
3. Nitric acid, is a colorless, corrosive liquid used in the manufacture of nitrogen fertilizers and
explosives. In an experiment to develop new explosives for mining operations, a 28.5 g sample of
nitric acid was poured into a beaker.
a.) How many moles of nitric acid are there in this sample?
b.) How many grams of nitrate ions were required?
c.) How many hydrogen ions were produced?
4. Hydrogen cyanide, HCN, is a volatile colorless liquid with the odor of certain frit pits (such as
peach and cherry pits). The compound is highly poisonous.
a.) How many molecules are there in 56 mg HCN, (this is the toxic dose).
b.) How many grams of CN were required?
c.) How many molecules of nitrogen were required?
5. Precious metals are commonly measured in troy ounces. A troy ounce is equal to 31.1 g. How
many moles are in a troy ounce of gold?
6. A chemist needs 22.0 g phenol, C61-1501-1, for an experiment. How many molecules of hydrogen
were required?
7. Calculate the mass of aluminum that would have the same number of atoms as 6.35 g of cadmium.
8. Americium is an element that does not occur naturally. It can be made in very small amounts in a
device called a particle accelerator. Calculate the mass in grams of a sample containing six atoms
of americium.
9. A silicon chip used in an integrated circuit of a microcomputer has. a mass of 5.68 mg. How many
silicon atoms are present in the chip?
10. Cobalt is a metal that is added to steel to improve its resistance to corrosion. If you started with a
sample of 5 X 10 20 atoms of cobalt:
a.) How many moles of cobalt do you have?
b.) Calculate the mass of the sample.
11. Calculate the molar mass of ammonium dichromate.
12. Which has the greatest mass? Show your work and circle the correct answer.
a.) 4.16 X 1023 atoms of radium
b.) 1.5 X 1020 atoms of cadium
c.) 1.33 X 10X24 atoms of argon.
13. How many grams of water must be used to obtain 7.50 mol of water?
b.) How many mL of water would that be?
) How many oxygen atoms would be in the sample?
14. Your uncle leaves you a barrel of nickels. You determine that the nickels weigh 1345 pounds and
that 50 nickels weigh 232 g. How many DOLLARS is the barrel of nickels worth?