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Chemistry µGCSE:

Formulas + Equations

10 quick questions - for GCSE and iGCSE

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10 minutes maximum! (can you do it in 5?)  
  1. Select the row which shows the correct charges on the ions formed by the metals in groups 1 and 2 and the non-metals in groups 6 and 7:
  Group 1 Group 2 Group 6 Group 7
A 1+ 2+ 6+ 7+
B 1- 2- 2+ 1+
C 1+ 2+ 2- 1-
D 7- 6- 2- 1-

2. Select the row showing the correct formulae for the compound ions:

  hydroxide carbonate sulfate nitrate
A OH- CO32- SO42- NO3-
B OH- CO32- SO42- NO32-
C OH2- CO3- SO4- NO3-
D OH2- CO3- SO32- NO3-

 

Q3-5: Which is the correct formula for each of the following compounds?

 

3. Calcium  chloride

  • A.  CaCl
  • B.  CaCl2
  • C.  Ca2Cl
  • D.  Ca7Cl2

4. Sodium carbonate

  • A. Na3CO
  • B. NaCO3
  • C. Na(CO3)2
  • D. Na2CO3

5. Lead(II)hydroxide

  • A. PbOH
  • B. Pb2OH
  • C. Pb(OH)2
  • D. PbOH2

6. In neutralization reactions the ions produced by acids join with the ion produced by alkalis. Which of these answers correctly identifies there ions?

  ion from acids ion from alkalis
A OH- H+
B OH2- H2+
C H+ OH-
D H+ OH2-
7. Marble chips react with dilute hydrochloric acid as follows:

CaCO3 (...) + 2HCl (...)  CaCl2 (…) + H2O (…) + CO2 (…)

The correct state symbols required to complete this equation are….
  • A.  CaCO3 (s) + 2HCl (aq)  CaCl2 (aq) + H2O (l) + CO2 (g)
  • B.  CaCO3 (s) + 2HCl (aq)  CaCl2 (l) + H2O (l) + CO2 (g)
  • C.  CaCO3 (s) + 2HCl (l)  CaCl2 (l) + H2O (l) + CO2 (g)
  • D.  CaCO3 (s) + 2HCl (l)  CaCl2 (aq) + H2O (aq) + CO2 (g)

 

Q8-10. Balance the following chemical equations:

8.   Mg + HCl MgCl2 + H2
9.  CH4 + O2 CO2 + H2O
10. Fe2O3 + CO Fe + CO2