Chemistry 0620 · IGCSE
Relative masses of atoms and molecules
60 practice questions on Relative masses of atoms and molecules, with worked solutions and instant marking.
The compound magnesium nitrate has the formula $\text{Mg(NO}_3\text{)}_2$. What is the relative formula mass for magnesium nitrate?
Feb/March 2016
Three chemical reactions are listed. 1 the catalytic addition of steam to ethene 2 the combustion of ethanol 3 the fermentation of glucose In which reaction does the relative molecular mass of the carbon-containing compound fall?
Feb/March 2018
What does the term relative atomic mass, $A_r$, mean?
Feb/March 2018
The relative formula mass, $M_r$, of calcium carbonate, $\text{CaCO}_3$, is $100$. How much carbon is contained in $100\,\text{g}$ of calcium carbonate?
Feb/March 2019
A compound is given by the formula $\text{XF}_2$ and has a relative mass of 70. Which element is X?
Feb/March 2021
A compound is given by the formula $\text{XF}_2$ and has a relative mass of 70. Which element is X?
Feb/March 2021
What is the relative molecular mass, $M_r$, for sulfur dioxide?
Feb/March 2024
Sulfur is placed in Group VI of the Periodic Table as an element.
Feb/March 2024
A 16.0\,\text{g} sample of the metal oxide, \text{MO}, is reduced to give 12.8\,\text{g} of the metal, \text{M}. What is the relative atomic mass, $A_r$, of M?
May/June 2016
What is the relative formula mass of ammonium nitrate, $\text{NH}_4\text{NO}_3$?
May/June 2017
When chlorine is reacted with hot concentrated aqueous sodium hydroxide, one product produced is sodium chlorate(V). The formula for sodium chlorate(V) is $\text{NaClO}_3$. What is the relative formula mass of sodium chlorate(V), $\text{NaClO}_3$?
May/June 2017
What is the relative formula mass for aluminium oxide, $\text{Al}_2\text{O}_3$?
May/June 2017
This question deals with masses, volumes and moles.
May/June 2018
The formula of the compound magnesium nitrate is $\text{Mg(NO}_3)_2$. What relative formula mass does magnesium nitrate have?
May/June 2019
Magnesium nitrate is represented by the formula $\text{Mg(NO}_3)_2$. What is its relative formula mass?
May/June 2019
Magnesium nitrate is shown by the formula $\text{Mg(NO}_3)_2$. What is the relative formula mass of magnesium nitrate?
May/June 2019
Calculate the relative formula mass of magnesium nitrate, $\text{Mg(NO}_3)_2$.
May/June 2021
Calculate the relative formula mass of magnesium nitrate, $\text{Mg(NO}_3)_2$.
May/June 2021
Calculate the relative formula mass of magnesium nitrate, $\text{Mg(NO}_3)_2$?
May/June 2021
$2.56\,\text{g}$ of the metal oxide, $\text{MO}_2$, is reduced to give $1.92\,\text{g}$ of the metal, M. What is the relative atomic mass of M?
May/June 2021
The relative atomic mass, $A_r$, of an element is found by comparing the mass of one atom of the element with the mass of one atom of element Q. What is Q?
May/June 2022
A compound formed from element X has the formula $\text{X}_2\text{O}$ and a relative formula mass of 144. What is element X?
May/June 2022
Nitrogen-containing compounds may be used as fertilisers. Which compound has the highest mass percentage of nitrogen?
May/June 2022
An element X forms a compound with formula $\text{X}_2\text{O}$, and this compound has a relative formula mass of $144$. Which element is X?
May/June 2022
What is the relative formula mass for ammonium nitrate, $\text{NH}_4\text{NO}_3$?
May/June 2023
State the relative formula mass of $\text{Mg(OH)}_2$.
May/June 2023
Magnesium nitrate is shown by the formula $\text{Mg(NO}_3)_2$. Calculate the relative formula mass of magnesium nitrate.
May/June 2023
What does relative molecular mass, $M_r$, mean?
May/June 2024
Define relative atomic mass.
May/June 2025
The relative formula mass, $M_r$, of calcium carbonate, $\text{CaCO}_3$, is 100. What mass of carbon is contained in $100\,\text{g}$ of calcium carbonate?
May/June 2025
Atoms contain electrons, neutrons and protons.
May/June 2025
What is the relative formula mass of magnesium nitrate, $\text{Mg(NO}_3\text{)}_2$?
Oct/Nov 2017
A compound with the formula $\text{XO}_2$ has a relative formula mass of 64. Which element is X?
Oct/Nov 2017
What is the relative formula mass for $\text{Mg(OH)}_2$?
Oct/Nov 2018
The formula for calcium phosphate is $\text{Ca}_3(\text{PO}_4)_2$. What is the relative formula mass of this compound?
Oct/Nov 2018
Which gas sample has the largest mass?
Oct/Nov 2018
During the thermal decomposition of 12.5 g of limestone (impure calcium carbonate), 5 g of calcium oxide are obtained. What mass of calcium oxide would be obtained from the thermal decomposition of 30 g of limestone?
Oct/Nov 2019
The relative atomic mass of chlorine is 35.5. In a calculation of relative atomic mass, the mass of a chlorine atom is compared with the mass of which particle?
Oct/Nov 2020
The relative atomic mass of chlorine is $35.5$. In relative atomic mass calculations, the mass of a chlorine atom is compared with the mass of which particle?
Oct/Nov 2020
The element sulfur occurs in several different minerals. Which mineral has the highest percentage by mass of sulfur?
Oct/Nov 2020
The relative atomic mass of chlorine is $35.5$. In a relative atomic mass calculation, the mass of a chlorine atom is compared with the mass of which particle?
Oct/Nov 2020
The relative atomic mass of chlorine is 35.5. When working out relative atomic mass, the mass of a chlorine atom is compared with the mass of which particle?
Oct/Nov 2020
Chlorine has a relative atomic mass of 35.5. When calculating relative atomic mass, what particle is used as the comparison for the mass of a chlorine atom?
Oct/Nov 2020
The element sulfur occurs in several different minerals. Which mineral has the highest percentage by mass of sulfur?
Oct/Nov 2020
The relative atomic mass of chlorine is $35.5$. In calculations of relative atomic mass, the mass of a chlorine atom is compared with the mass of which particle?
Oct/Nov 2020
Sodium chlorate(V) is written as $\text{NaClO}_3$. What is the relative formula mass of sodium chlorate(V), $\text{NaClO}_3$?
Oct/Nov 2021
Sodium chlorate(V) can be represented by the formula $\text{NaClO}_3$. What is the relative formula mass of sodium chlorate(V), $\text{NaClO}_3$?
Oct/Nov 2021
Sodium chlorate(V) has the formula $\text{NaClO}_3$. Calculate the relative formula mass of sodium chlorate(V), $\text{NaClO}_3$.
Oct/Nov 2021
Lead is a metallic element in Group IV. Galena is one of its ores and it is an impure form of lead(II) sulfide, PbS. Another lead ore is cerussite, which contains lead(II) carbonate, PbCO$_3$.
Oct/Nov 2021
What is the relative formula mass for ammonium sulfate, $(\text{NH}_4)_2\text{SO}_4$?
Oct/Nov 2022
A test-tube contains 12.4 g of copper(II) carbonate, which is then heated. Just 50% breaks down. $[M_r: \text{CuCO}_3 = 124; \text{CuO} = 80]$. What is the final mass of the substances left in the test-tube?
Oct/Nov 2022
A compound that includes element X has the formula $\text{Na}_2\text{X}_2\text{O}_3$. Its relative formula mass is $158$. What is the relative atomic mass for X?
Oct/Nov 2023
Calcium nitrate is represented by the formula $\text{Ca(NO}_3)_2$. What is the relative formula mass, $M_r$, for calcium nitrate?
Oct/Nov 2023
A compound that contains element X has the formula $\text{Na}_2\text{X}_2\text{O}_3$. Its relative formula mass is $158$. What is the relative atomic mass of X?
Oct/Nov 2023
What is the relative molecular mass, $M_r$, for sulfuric acid, $\text{H}_2\text{SO}_4$?
Oct/Nov 2024
What is the relative formula mass for magnesium bromide?
Oct/Nov 2024
For calcium sulfate, $\mathrm{CaSO}_4$, what is the relative formula mass?
Oct/Nov 2025
What is the relative formula mass, $M_r$, for calcium hydroxide, $\mathrm{Ca(OH)_2}$?
Oct/Nov 2025
The combustion equation for ethanol is shown below. $\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}$. The relative molecular mass, $M_r$, of ethanol is 46. Which statement about this reaction is correct?
Oct/Nov 2025
Which two quantities are used to work out the relative atomic mass of a sample of boron?
Oct/Nov 2025