1. Calculate the number of atoms in
(a) 18.0g of carbon, C.
(b) 18.0g of copper, Cu.
(c) 7.20g of sulfur, S8.
2. Calculate the number of molecules in
(a) 1.00g of ammonia, NH3.
(b) 3.28g of sulfur dioxide, SO2.
(c) 7.83g of hydrogen chloride, HCl.
3. Calculate the number of ions in
(a) 0.500mol of sodium chloride, NaCl [Na+,Cl-]
(b) 14.6g of sodium chloride, NaCl.
(c) 18.5g of clacium chloride, CaCl2.
4. Calculate the amount of hydrogen molecules, H2 in 3*1023
molecules if the Avogadro number is 6*1023.
5. Calculate the Avogadro number if 1.5*1023 mol of helium atoms He
has a mass of 1g.
Answers
1(a) 9.03*1022, (b) 1.71*1022, (c)
1.35*1023.
2(a) 3.54*1022 , (b) 3.08*1022 (c) 1.29*1023
.
3(a)6.02*1023. (b)3.01*1023 , (c) 3.01*1023
.
4. 0.5mol
5. 6*1023