Converting From Moles to Mass
Sample Problem (p. 58)
A flask contains 0.750 mol of carbon dioxide gas, CO2.
What mass of carbon dioxide gas is in this sample?
i) M CO2 = 1 MC + 2 MO = 12.01g/mol + 2 (16.00g/mol)
= 44.01g/mol
ii) (0.750 mol CO2)(44.01g) = 33.0075 g = 33.0 g
1 mol
Converting From Mass to Moles
Sample Problem (p. 60)
How many moles of acetic acid, CH3COOH, are in a 23.6 g
sample?
i) The molar mass of CH3COOH is:
(12.01 × 2) + (16.00 × 2) + (1.01 × 4) = 60.06 g/mol
ii) 23.6 g x 1 mol = 0.393 mol
60.06 g
Check Your Solution
23.6 g represents a little more than 1/3rd of the molar mass. This
indicates that the sample should contain just over 1/3 rd of a mole,
which means that our answer makes sense.
Please complete questions p.59 [#20, 21(a)], p.60 (#24, 26)