Define relative atomic mass ( A r ).

The relative atomic mass ( A r ) is the average mass of the isotopes of an element compared to 1/12th of the mass of a carbon-12 atom. It can be found on the Periodic Table.

The relative molecular mass ( M r ) of a compound is calculated by adding up the ______ of all atoms in the formula For H 2 O ( A r : H = 1, O = 16), the M r = ______ .

The relative molecular mass ( M r ) of a compound is calculated by adding up the (relative atomic) mass of all atoms in the formula For H 2 O ( A r : H = 1, O = 16), the M r = 18 .

True or False? The terms "relative molecular mass" and "relative formula mass" mean the same thing and can be used interchangeably for any compound.

False. Relative molecular mass ( M r ) is used for covalent compounds (discrete molecules). Relative formula mass is used for ionic compounds. The correct term depends on the type of compound.

Calculate the relative formula mass of calcium carbonate, CaCO 3 . ( A r : Ca = 40, C = 12, O = 16)

M r of CaCO 3 = 40 + 12 + (3 x 16) = 100

True or False? In a chemical reaction, the total mass of the products always equals the total mass of the reactants.

True. The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. The total mass of reactants always equals the total mass of products.

The relative formula mass of MgCl 2 ( A r : Mg = 24, Cl = 35.5) is ______ .

M r of MgCl 2 = 24 + (2 x 35.5) = 95

O LevelChemistryCambridge (CIE)Flashcards3. Stoichiometry3.2 Relative Masses of Atoms & Molecules

3.2 Relative Masses of Atoms & Molecules (Cambridge (CIE) O Level Chemistry): Flashcards

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Define relative atomic mass (A_r).

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Define relative atomic mass (A_r).
The relative atomic mass (A_r) is the average mass of the isotopes of an element compared to 1/12th of the mass of a carbon-12 atom. It can be found on the Periodic Table.
The relative molecular mass (M_r) of a compound is calculated by adding up the ______ of all atoms in the formula
For H₂O (A_r: H = 1, O = 16), the M_r = ______.
The relative molecular mass (M_r) of a compound is calculated by adding up the (relative atomic) mass of all atoms in the formula
For H₂O (A_r: H = 1, O = 16), the M_r = 18.
True or False?
The terms "relative molecular mass" and "relative formula mass" mean the same thing and can be used interchangeably for any compound.
False.
Relative molecular mass (M_r) is used for covalent compounds (discrete molecules).
Relative formula mass is used for ionic compounds.
The correct term depends on the type of compound.
Calculate the relative formula mass of calcium carbonate, CaCO₃.
(A_r: Ca = 40, C = 12, O = 16)
M_r of CaCO₃ = 40 + 12 + (3 x 16) = 100
True or False?
In a chemical reaction, the total mass of the products always equals the total mass of the reactants.
True.
The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. The total mass of reactants always equals the total mass of products.
The relative formula mass of MgCl₂ (A_r: Mg = 24, Cl = 35.5) is ______.
M_r of MgCl₂ = 24 + (2 x 35.5) = 95

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