# Chemical Calculations - definitions

Relative Atomic Mass
The average mass of an ATOM compared to 1/12 the mass of an atom of 12C.
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Relative Isotopic Mass
The mass of an ATOM compared to 1/12 the mass of an atom of 12C.
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Relative molecular mass
The AVERAGE mass of a MOLECULE compared to 1/12 the mass of an atom of 12C.
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Relative Formula Mass
The AVERAGE mass of ONE FORMULA UNIT compared to 1/12 the mass of an atom of C12.
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Mole
A mole is the amount of a substance that contains the same number of particles as there are atoms of carbon in exactly 12g of 12C.
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Empirical Formula
The simplest whole number ratio of atoms (or ions) present in a compound.
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Molecular Formula
The actual number of atoms present in a compound.
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Calculations Involving Gas Volumes
At room temperature and pressure (r.t.p), one mole of any gas occupies 24dm3 of space.
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% Yield
The actual mass obtained/the theoretical mass possible X 100
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Atom Economy
The formula mass of desired products/total formula masses of reactants X 100
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## Other cards in this set

### Card 2

#### Front

The mass of an ATOM compared to 1/12 the mass of an atom of 12C.

#### Back

Relative Isotopic Mass

### Card 3

#### Front

The AVERAGE mass of a MOLECULE compared to 1/12 the mass of an atom of 12C.

### Card 4

#### Front

The AVERAGE mass of ONE FORMULA UNIT compared to 1/12 the mass of an atom of C12.

### Card 5

#### Front

A mole is the amount of a substance that contains the same number of particles as there are atoms of carbon in exactly 12g of 12C.