Quantitative Chemistry questions

By Interwoven Maths

Quantitative Chemistry question collection

Review Quantitative Chemistry questions for Chemistry, with correct answers shown and coverage across relative formula mass; moles and reacting masses; concentration calculations.

Back to Quantitative Chemistry practice Back to Chemistry

Question 1

What does conservation of mass mean in a closed reaction system?
  1. Total reactant mass equals total product mass
  2. Product mass is lower when a gas forms
  3. Product mass is higher when oxygen reacts
  4. Mass is conserved for solids but not gases

Question 2

Why can measured mass fall when magnesium reacts with acid in an open flask?
  1. Hydrogen gas escapes
  2. Atoms are destroyed
  3. The balance subtracts liquid mass
  4. Magnesium gains negative mass

Question 3

Which equation is correctly balanced?
  1. \(\mathrm{Mg} + 2\mathrm{HCl} \to \mathrm{MgCl}_{2} + \mathrm{H}_{2}\)
  2. \(\mathrm{Mg} + \mathrm{HCl} \to \mathrm{MgCl} + \mathrm{H}_{2}\)
  3. \(2\mathrm{Mg} + \mathrm{HCl} \to \mathrm{MgCl}_{2} + \mathrm{H}_{2}\)
  4. \(\mathrm{Mg} + 2\mathrm{HCl} \to \mathrm{MgCl} + \mathrm{H}_{2}\)

Question 4

What is the relative formula mass, Mr, of CaCO3? (Ca = \(40\), C = \(12\), O = \(16\))?
  1. \(100\)
  2. \(84\)
  3. \(88\)
  4. \(116\)

Question 5

What is the Mr of MgCl2? (Mg = \(24\), Cl = \(35.5\))?
  1. \(95\)
  2. \(71\)
  3. \(59.5\)
  4. \(119\)

Question 6

What is the percentage by mass of oxygen in MgO? (Mg = \(24\), O = \(16\))?
  1. \(40\%\)
  2. \(60\%\)
  3. \(25\%\)
  4. \(16\%\)

Question 7

What is the percentage by mass of carbon in CO2? (C = \(12\), O = \(16\))?
  1. \(27.3\%\)
  2. \(12\%\)
  3. \(44\%\)
  4. \(72.7\%\)

Question 8

Which formula is used for concentration in \(\mathrm{g\,dm^{-3}}\)?
  1. concentration = mass (\(\mathrm{g}\)) / volume (\(\mathrm{dm^3}\))
  2. concentration = volume / mass
  3. concentration = mass x volume
  4. concentration = mass - volume

Question 9

What is \(250\,\mathrm{cm^3}\) in \(\mathrm{dm^3}\)?
  1. \(0.250\,\mathrm{dm^3}\)
  2. \(2.50\,\mathrm{dm^3}\)
  3. \(25.0\,\mathrm{dm^3}\)
  4. \(0.025\,\mathrm{dm^3}\)

Question 10

How much solute is needed to make \(0.50\,\mathrm{dm^3}\) of a \(20\,\mathrm{g\,dm^{-3}}\) solution?
  1. \(10\,\mathrm{g}\)
  2. \(40\,\mathrm{g}\)
  3. \(0.04\,\mathrm{g}\)
  4. \(20\,\mathrm{g}\)

Question 11

\(5.0\,\mathrm{g}\) of salt are dissolved to make \(200\,\mathrm{cm^3}\) solution. What is the concentration in \(\mathrm{g\,dm^{-3}}\)?
  1. \(25\,\mathrm{g\,dm^{-3}}\)
  2. \(2.5\,\mathrm{g\,dm^{-3}}\)
  3. \(10\,\mathrm{g\,dm^{-3}}\)
  4. \(250\,\mathrm{g\,dm^{-3}}\)

Question 12

What identifies the limiting reactant?
  1. It is used up first and stops more product forming
  2. It has the largest starting mass
  3. It has the first coefficient in the equation
  4. It speeds the reaction without being consumed

Question 13

\(\mathrm{CaCO}_3 \to \mathrm{CaO} + \mathrm{CO}_2\). If \(25\,\mathrm{g}\) of \(\mathrm{CaCO}_3\) decomposes completely, what mass of \(\mathrm{CO}_2\) is formed? (Mr: \(\mathrm{CaCO}_3 = 100\), \(\mathrm{CO}_2 = 44\))?
  1. \(11\,\mathrm{g}\)
  2. \(4.4\,\mathrm{g}\)
  3. \(22\,\mathrm{g}\)
  4. \(44\,\mathrm{g}\)

Question 14

A reaction has a theoretical yield of \(8.0\,\mathrm{g}\) and an actual yield of \(6.0\,\mathrm{g}\). What is the percentage yield?
  1. \(75\%\)
  2. \(133\%\)
  3. \(25\%\)
  4. \(48\%\)

Question 15

Which can make percentage yield less than 100%?
  1. Losing product during separation
  2. Using a balanced symbol equation
  3. Calculating relative formula masses
  4. Adding a catalyst that remains unchanged

Question 16

What does atom economy measure?
  1. Percentage of reactant mass in the desired product
  2. Percentage of theoretical product actually obtained
  3. Percentage by mass of one element
  4. Product mass made per second

Question 17

Why is high atom economy desirable?
  1. Less waste and more efficient raw-material use
  2. A higher percentage yield
  3. A faster reaction rate
  4. A lower activation energy

Question 18

For concentrations in mol/dm3, what is the equation for moles?
  1. moles = concentration x volume (in \(\mathrm{dm^3}\))
  2. moles = concentration / volume
  3. moles = mass x volume
  4. moles = volume / concentration x 1000

Question 19

At room temperature and pressure, what volume does \(1\,\mathrm{mol}\) of gas occupy?
  1. \(24\,\mathrm{dm^3}\)
  2. \(2.4\,\mathrm{dm^3}\)
  3. \(240\,\mathrm{dm^3}\)
  4. \(12\,\mathrm{dm^3}\)

Question 20

\(0.50\,\mathrm{mol}\) of gas at RTP has what volume?
  1. \(12\,\mathrm{dm^3}\)
  2. \(24\,\mathrm{dm^3}\)
  3. \(6\,\mathrm{dm^3}\)
  4. \(48\,\mathrm{dm^3}\)

Question 21

What is one mole?
  1. The amount containing Avogadro’s number of particles
  2. The mass of one gram of a substance
  3. The number of atoms in one molecule
  4. The volume of one litre of gas

Question 22

Which equation gives the number of moles \(n\) from mass \(m\) and relative formula mass \(M_r\)?
  1. \(n=\frac{m}{M_r}\)
  2. \(n=mM_r\)
  3. \(n=\frac{M_r}{m}\)
  4. \(n=m+M_r\)

Question 23

Which unit is used for amount concentration?
  1. mol dm⁻³
  2. g dm⁻³
  3. mol
  4. dm³

Question 24

What is the equation for concentration?
  1. \(c=\frac{n}{V}\)
  2. \(c=nV\)
  3. \(c=\frac{V}{n}\)
  4. \(c=n+V\)

Question 25

Which ratio defines percentage yield?
  1. Actual yield divided by theoretical yield
  2. Theoretical yield divided by actual yield
  3. Desired product mass divided by reactant mass
  4. Solute mass divided by solution volume

Question 26

What is theoretical yield?
  1. Maximum product predicted from the reacting amounts
  2. Product actually collected after separation
  3. Reactant left after the reaction stops
  4. Waste predicted by atom economy

Question 27

What does an empirical formula show?
  1. Simplest whole-number ratio of atoms
  2. Actual number of atoms in one molecule
  3. Percentage of atoms in the desired product
  4. Total mass of one mole of compound

Question 28

Which ratio is used to calculate percentage uncertainty?
  1. Absolute uncertainty divided by measured value
  2. Measured value divided by absolute uncertainty
  3. Actual yield divided by theoretical yield
  4. Mass divided by volume

Question 29

At the same temperature and pressure, which gas samples have equal volumes?
  1. Samples containing equal numbers of moles
  2. Samples with equal masses
  3. Samples with equal relative formula masses
  4. Samples containing equal numbers of elements

Question 30

What happens to an excess reactant?
  1. Some remains when the reaction stops
  2. It is used up before the limiting reactant
  3. It becomes a catalyst
  4. It determines the maximum product alone

About this topic

Review Quantitative Chemistry questions for Chemistry, with correct answers shown and coverage across relative formula mass; moles and reacting masses; concentration calculations.

This topic covers

Example question types