Formulas — Paper 2 · IGCSE Sciences - Co-ordinated (Double) 0654

15 How many atoms of metals and of non-metals are shown in the formula Na2SO4? atoms of atoms of metals non-metals A 1 1 B 1 2 C 2 4 D 2 5

1 marks

Answer: D

This question in 0654/21 May/June 2017

16 How many atoms of metals and of non-metals are shown in the formula Na2SO4? atoms of atoms of metals non-metals A 1 1 B 1 2 C 2 4 D 2 5

1 marks

Answer: D

This question in 0654/22 May/June 2017

15 How many atoms of metals and of non-metals are shown in the formula Na2SO4? atoms of atoms of metals non-metals A 1 1 B 1 2 C 2 4 D 2 5

1 marks

Answer: D

This question in 0654/23 May/June 2017

17 Cryolite is a mineral which contains aluminium, sodium and fluorine. It contains twice as many fluorine atoms as sodium atoms. It contains three times as many sodium atoms as aluminium atoms. What is the formula of cryolite? A NaAl 3F6 B Na2Al F4 C Na3Al F6 D Na3Al F4

1 marks

Answer: C

This question in 0654/22 Oct/Nov 2018

17 Sodium phosphate, Na3PO4, contains sodium ions, Na+. Aluminium sulfate, Al 2(SO4)3, contains sulfate ions, SO4 2–. What is the formula of aluminium phosphate? A Al PO4 B Al (PO4)2 C Al 2(PO4)3 D Al 3(PO4)2

1 marks

Answer: A

This question in 0654/23 May/June 2019

17 The charges on some ions are shown. positive ions negative ions Al 3+ N3– Li+ NO3 – Mg2+ O2– Zn2+ SO4 2– Which formula is correct? compound formula A aluminium sulfate Al 2(SO4)3 B lithium nitrate Li2NO3 C magnesium nitride Mg2N3 D zinc oxide ZnO2

1 marks

Answer: A

This question in 0654/21 May/June 2021

14 The structures of some substances are shown. water ethanol methane Which row shows the total number of different elements and the total number of atoms in the three structures? total total number of number of different atoms elements A 3 9 B 3 17 C 7 9 D 7 17

1 marks

Answer: B

This question in 0654/22 May/June 2021

17 Phosphoric acid contains phosphate ions, PO4 3–. Phosphoric acid reacts with calcium hydroxide, Ca(OH)2, to form the salt calcium phosphate. What is the formula of calcium phosphate? A CaPO4 B Ca(PO4)3 C Ca2PO4 D Ca3(PO4)2

1 marks

Answer: D

This question in 0654/22 May/June 2021

16 Sodium phosphate, Na3PO4, contains sodium ions, Na+. Aluminium sulfate, Al 2(SO4)3, contains sulfate ions, SO4 2–. What is the formula of aluminium phosphate? A Al PO4 B Al (PO4)2 C Al 2(PO4)3 D Al 3(PO4)2

1 marks

Answer: A

This question in 0654/21 May/June 2022

16 Sodium phosphate, Na3PO4, contains sodium ions, Na+. Aluminium sulfate, Al 2(SO4)3, contains sulfate ions, SO4 2–. What is the formula of aluminium phosphate? A Al PO4 B Al (PO4)2 C Al 2(PO4)3 D Al 3(PO4)2

1 marks

Answer: A

This question in 0654/22 May/June 2022

16 Sodium phosphate, Na3PO4, contains sodium ions, Na+. Aluminium sulfate, Al 2(SO4)3, contains sulfate ions, SO4 2–. What is the formula of aluminium phosphate? A Al PO4 B Al (PO4)2 C Al 2(PO4)3 D Al 3(PO4)2

1 marks

Answer: A

This question in 0654/23 May/June 2022

17 Which symbol equation is not balanced? A C3H8 + 5O2  3CO2 + 4H2O B Fe3O4 + 2H2  3Fe + 2H2O C Mg(OH)2 + 2HCl  MgCl 2 + 2H2O D 2Na + 2H2O  2NaOH + H2

1 marks

Answer: B

This question in 0654/21 May/June 2023

17 Aqueous potassium bromide reacts with aqueous silver nitrate to produce a cream precipitate. What is the ionic equation for this reaction? A Ag+(aq) + Br–(aq)  AgBr(s) B Ag2+(aq) + 2Br–(aq)  AgBr2(s) C K+(aq) + NO3 –(aq)  KNO3(s) D 2K+(aq) + NO3 2–(aq)  K2NO3(s)

1 marks

This question in 0654/22 May/June 2023

16 Pentane, C5H12, burns in a limited air supply to produce some carbon dioxide and some carbon monoxide. What is a balanced equation for this reaction? A C5H12 + 7O2  3CO2 + 2CO + 6H2O B C5H12 + 9O2  CO2 + 4CO + 12H2O C C5H12 + 14O  3CO2 + 2CO + 6H2O D C5H12 + 18O  CO2 + 4CO + 12H2O

1 marks

Answer: A

This question in 0654/23 May/June 2023

16 When dilute sodium hydroxide is added to aqueous iron(II) sulfate, insoluble iron(II) hydroxide and aqueous sodium sulfate are formed. What is the ionic equation for this reaction? A Fe2+(aq) + 2OH–(aq)  Fe(OH)2(s) B Fe2+(aq) + SO4 2–(aq) + 2Na+(aq) + 2OH–(aq)  Fe(OH)2(s) + 2Na+(aq) + SO4 2–(aq) C FeSO4(aq) + 2NaOH(aq)  Fe(OH)2(s) + Na2SO4(aq) D SO4 2–(aq) + 2Na+(aq)  Na2SO4(aq)

1 marks

Answer: A

This question in 0654/22 Oct/Nov 2023

17 The formula of an ammonium ion is NH4 +. The formula of a phosphate ion is PO4 3–. What is the formula of ammonium phosphate? A (NH4)3PO4 B (NH4)2PO4 C NH4PO4 D NH4(PO4)3

1 marks

Answer: A

This question in 0654/21 Oct/Nov 2024

16 Copper reacts with dilute nitric acid to form copper(II) nitrate, nitrogen dioxide and water. The equation for the reaction is shown. Cu(s) + q HNO3(aq)  Cu(NO3)2(aq) + s NO2(g) + t H2O(l) Which row shows the numerical values of q and s? q s A 2 1 B 2 2 C 4 1 D 4 2

1 marks

Answer: D

This question in 0654/22 Feb/March 2025

18 What is the balanced equation for the combustion of hydrogen? A 2H + O  H2O B H2 + O2  H2O C H2 + O  H2O D 2H2 + O2  2H2O

1 marks

Answer: D

This question in 0654/21 May/June 2025