GCSE 1.7 Quantitative Chemistry

What is the relative atomic mass (Aᵣ) of an atom compared to?

• The mass of a hydrogen atom

• The mass of a carbon-12 isotope

• The mass of an oxygen-16 isotope

• The mass of a nitrogen-14 isotope

How is the relative formula mass (Mᵣ) of a compound calculated?

• By adding the atomic numbers of all atoms in the compound

• By adding the relative atomic masses of all atoms in the compound

• By multiplying the atomic numbers of all atoms in the compound

• By dividing the relative atomic masses of all atoms in the compound

What is the mass of one mole of a substance in grams numerically equal to?

• The atomic number of the substance

• The relative formula mass of the substance

• The number of atoms in the substance

• The volume of the substance

What is the theoretical yield in a chemical reaction?

• The actual amount of product obtained

• The maximum amount of product that can be obtained

• The amount of reactants used

• The percentage of product obtained

Why might the percentage yield of a product be less than 100%?

• Due to the exact measurement of reactants

• Because of side reactions or reversible reactions

• Because the reaction goes to completion

• Due to the purity of reactants

What does the term "anhydrous" refer to in chemistry?

• A substance containing water

• A substance without water

• A substance with a high boiling point

• A substance with a low melting point

How can water of crystallisation be removed from a compound?

• By dissolving the compound in water

• By heating the compound to constant mass

• By cooling the compound to low temperatures

• By mixing the compound with another substance

What is the empirical formula of a compound?

• The simplest whole-number ratio of atoms in the compound

• The actual number of atoms in the compound

• The molecular formula of the compound

• The structural formula of the compound

What is the relative formula mass (Mᵣ) of Ca(NO₃)₂?

• 102

• 164

• 128

• 150

How do you calculate the percentage of an element by mass in a compound?

• (mass of element in the compound / relative formula mass) × 100

• (relative formula mass / mass of element in the compound) × 100

• (mass of element in the compound × relative formula mass) / 100

• (relative formula mass × 100) / mass of element in the compound