# Chemical Quantities Mole Mass Relationships

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```					Chapter 10: Chemical Quantities

Mole-Mass Relationships
Mrs. Russotto
Mole – Mass Relationships
   Use the molar mass of an element or compound to
convert between the mass of a substance and the moles
of a substance
Converting Moles to Mass
   Aluminum satellite dishes are resistant to
corrosion because the aluminum reacts with
oxygen in the air to form a coating of aluminum
oxide (Al2O3). What is the mass of 9.45 mol of this
tough, resistant coating?
Known                       Unknown
9.45 mol Al2O3              ? g Al2O3
Molar mass of Al2O3
Calculate Molar Mass
Al = 27.0    X2      = 54.0 g        Therefore:
O = 16.0     X 3 + = 48.0 g           102.0 g Al2O3 = 1 mol Al2O3

102.0 g
9.45 mol Al2O3   102.0 g Al2O3          =
1 mol Al2O3

963.9 g Al2O3   = 964 g Al2O3
   Find the mass of 0.452 mol C20H42 in grams.
Converting Mass to Moles
   When iron is exposed to air, it corrodes to form
red-brown rust. Rust is iron(III) oxide (Fe2O3).
How many moles of iron(III) oxide are contained in
92.2 g of pure Fe2O3?
Known                   Unknown
92.2 g Fe2O3            ? mol Fe2O3
Molar mass of Fe2O3
Calculate Molar Mass
Fe = 55.8   X 2 = 111.6 g Therefore:
O = 16.0    X 3 + = 48.0 g 159.6 g Fe2O3 = 1 mol Fe2O3
159.6 g
92.2 g Fe2O3   1 mol Fe2O3               =
159.6 g Fe2O3

0.577694 mol Fe2O3 = 0.578 mol Fe2O3