Moles (HT only) Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher

How is a substance’s relative formula mass related to the mass of one mole of it?

The mass of one mole in grams is numerically equal to its relative formula mass.

How do you calculate the amount in moles from a substance’s mass in grams and its relative formula mass?

Divide the mass in grams by the relative formula mass.

How do you calculate the mass in grams from an amount in moles and the substance’s relative formula mass?

Multiply the amount in moles by the relative formula mass.

What do coefficients in a balanced chemical equation represent in terms of amount of substance?

The fixed mole ratio in which substances react and are formed.

What is the mole ratio of magnesium, hydrochloric acid, magnesium chloride and hydrogen in $\ce{Mg + 2HCl -> MgCl2 + H2}$?

$1:2:1:1$

How are mole ratios used in chemical calculations?

They determine how much of one substance is needed or produced from a known amount of another.

What must be done to a chemical equation before using it for an amount calculation?

Balance the equation.