Formula and molecular mass

The relative atomic mass is the average mass of an atom compared to 

• the mass of a oxygen-16 atom.

• 1/12 the mass of a carbon-12 atom
• the mass of a hydrogen atom
• 1/12 the mass of a hydrogen atom

The relative molecular mass of a compound is equal to the sum of its

• Atomic mass
• Atomic number
• Oxidation number
• Valence electrons

What is the relative molecular mass of fluorine gas, F₂? (Ar F:19)

• 19

• 38

• 9

• 18

What is the unit of relative molecular mass?

• kilogram
• gram
• gram per mole (g/mol)
• no units

The formula of a compound is Mg(OH)₂. Given that the M_r of the compound is 58, calculate the A_r of Mg. (Ar, H:1, O:16)

• 32

• 24

• 81

• 94

The formula of a compound is Ca(NO₃)_2, calculate and define the Mr of this compound. (Ar, N:14, O:16, Ca:40)

• 150- relative formula mass

• 150- relative molecular mass

• 164- relative molecular mass

• 164- relative formula mass

The formula of a compound is Al₂(SO₄)_{3 ,} calculate the relative formula mass (Mr) of this compound. (Ar, Al:27, O:16, S:32)

• 256

• 246

• 150

• 342

The formula of a compound is C₃H₇COOH_, calculate the relative molecular mass (Mr) of this compound. (Ar, C:12, O:16, H:1)

• 56

• 88

• 150

• 74

The formula of a compound is C₅H₁₁OH _, calculate and define the Mr of this compound. (Ar, C:12, O:16, H:1)

• 88- relative molecular mass

• 88- relative formula mass

• 87- relative molecular mass

• 87- relative formula mass

The formula of a compound is NH₄NO_{3 ,} calculate and define the Mr of this compound. (Ar, N:14, O:16, H:1)

• 80- relative molecular mass

• 80- relative formula mass

• 66- relative molecular mass

• 66- relative formula mass