(a) 3 molecules of carbon dioxide(CO2);
(b) 2 molecules of silicon tetrafluoride(SiF4);
(c) 5 molecules of nitric acid(HNO3).
2. A sample of ammonia(NH3) contains 7.22 moles of ammonia.
(a) How many molecules of ammonia are in the sample?
(b) A second sample of ammonia contains 3.87 x 10^21 molecules of ammonia. How many moles of ammonia are in the sample?
3. A crystal of calcium chloride(CaCl2) contains 2.39 moles of CaCl2.
(a) How many formula units of CaCl2 are present?
(b) How many cations ( Ca^2+) are present?
(c) how many anions ( Cl^1-) are present?
4. Find the molar masses of the following substances: (a) sodium sulfate(Na2SO4);
(b) dinitrogen tetroxide(N2O4).
5. Calculate the number of moles of sulfur dioxide(SO2) in 76.1 g SO2.
6.. Suppose that a pure copper coin has a mass of 3.22 g. How many moles of copper(Cu) are in the coin?
7.. A sample of silver nitrate(AgNO3) has a mass of 255.4 g. How many formula units of silver nitrate are present in the sample?
8.. Suppose that a sample of the molecular substance carbon tetrabromide(CBr4) has a mass of 7.57 grams. Calculate:
(a) the number of moles
(b) the number of molecules.
9. A student is given 9.15 x 10^21 formula units of ammonium sulfate, (NH4)2SO4, and is asked to determine its mass. What should the student find the mass of the sample to be?
10. Calculate the volume of a balloon filled with 15.0 grams of nitrogen dioxide(NO2) gas at standard temperature and pressure.