MOLE UNIT REVIEW WKST Answers

MOLE UNIT REVIEW WORKSHEET

1. Convert 500.0 g NaCl to formula units. 5.15 x 1024 f.u.
Convert 9.8 x 1024 molecules of C2H6 to grams. 4.9 x 102 g
The mass of an unknown gas is 11.59 g. The mass of an equal volume of He is 1.45 g. Calculate the molar mass of the unknown gas. 32.0 g/mol
Calculate the percentage composition of sulphur in Al2(SO4)3. 28.11%
Calculate the molar mass of Co2(SO4)3•6H2O 514.16 g/mol
The empirical formula for a compound is C2H5O and its molecular mass is 135 g/mol. Determine the molecular formula. C6H15O3
A compound is 24.4% Ca, 17.1% N and 58.5% 0. Calculate the empirical formula. CaN2O6
Find the number of atoms in 7.6 g of sodium phosphide.
7.6 g x 1 mol x 6.02 x 1023 molecules x 4 atoms Na3P = 1.8 x 1023 atoms 99.94 g 1 mol 1 molecules
How many C atoms in 60.5 g of sucrose? C12H22O11 molar mass = 342.34 g/mol
60.5g x 1 mol x 6.02 x 1023 molecules x 12 atoms C = 1.28 x 1024 atoms 342.34 g 1 mol 1 molecules
If 3.75 x 1024 atoms of hydrogen are found in a sample of ammonium chloride, what mass of ammonium chloride is present? NH4Cl M= 53.50 g/mol
3.75 x 1024 atoms H x 1 molecule x 1 mol x 53.50 g = 83.3g 4 atoms H 6.02 x 1023 molec 1 mol
How many molecules in a) 7.56 g of bromine gas.
7.56 g x 1 mol x 6.02 x 1023 molecules = 2.85 x 1022 molecules 159.80 g 1 mol b) 88.55g of carbon monoxide gas.
88.55 g x 1 mol x 6.02 x1023 molecules = 1.90 x 1024 molecules 28.01 g 1 mol c) 18.6L of chlorine gas (at STP)
18.6L x 1 mol x 6.02 x 1023 molecules = 5.00 x 1023 molecules 22.4 L 1 mol