Amount of substance with PDF A level

What is the mole defined as in chemical calculations?

• The mass in grams of 1 mole of a substance

• The amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12

• The volume of 1 mole of a gas at room temperature and pressure

• The number of atoms in 1 gram of carbon-12

What does the relative atomic mass represent?

• The mass of 1 mole of a substance in grams

• The average mass of one atom compared to one twelfth of the mass of one atom of carbon-12

• The volume of 1 mole of a gas at room temperature and pressure

• The number of atoms in 12 grams of carbon-12

What is the molar mass of a substance?

• The volume of 1 mole of a gas at room temperature and pressure

• The number of particles in 1 mole of a substance

• The mass in grams of 1 mole of a substance

• The number of atoms in 12 grams of carbon-12

What is the molar gas volume at room temperature (25°C) and pressure (1 atm)?

• 22.4 dm³ mol⁻¹

• 24 dm³ mol⁻¹

• 12 dm³ mol⁻¹

• 6.02 x 10²³ dm³ mol⁻¹

How many atoms are there in 12 grams of carbon-12 according to Avogadro's constant?

• 6.02 x 10²³ atoms

• 12 x 10²³ atoms

• 24 x 10²³ atoms

• 1 x 10²³ atoms

What is the formula to calculate the amount in moles for pure solids, liquids, and gases?

• Amount in mol = mass x Mr

• Amount in mol = mass / Mr

• Amount in mol = Mr / mass

• Amount in mol = mass + Mr

When dealing with significant figures in answers, what should you do if given a mixture of different significant figures?

• Use the largest number of significant figures

• Use the average number of significant figures

• Use the smallest number of significant figures

• Round up to the nearest whole number

What is an empirical formula?

• A) A formula that shows the full number of atoms in a compound

• B) The simplest ratio of atoms of each element in the compound

• C) A formula that represents the molecular mass of a compound

• D) The detailed structural representation of a compound

Which of the following can be used to calculate the empirical formula?

• A) Masses of each element in the compound

• B) Volume of each element in the compound

• C) Density of each element in the compound

• D) Boiling point of each element in the compound

What is the molecular formula?

• A) The simplest ratio of atoms of each element in the compound

• B) The actual number of atoms of each element in the compound

• C) The formula that represents the ionic charges in a compound

• D) The formula that shows the physical state of a compound