Why things conduct electricity
3 marks · EasyThe table shows the state of three substances at room temperature:
| Substance | State |
|---|---|
| Calcium bromide | Solid |
| Ethanol | Liquid |
| Magnesium sulfate (aq) | Solution |
Which one of these substances is most likely to conduct electricity? State your answer.
State the type of particles that must be present and able to move for conduction to occur in this substance.
Explain why the other two substances do not conduct electricity at room temperature.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a(i)) Magnesium sulfate (aq)
(a(ii)) Ions
(a(iii)) Calcium bromide is solid so its ions cannot move. Ethanol is a covalent compound, so there are no ions to carry charge.
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Marking points
A1 (a(i)) · 1 mark · Correctly identifies magnesium sulfate (aq).
A2 (a(ii)) · 1 mark · Correctly states ions (must mention ions, not electrons).
A3 (a(iii)) · 1 mark · Mentions calcium bromide is solid so ions not free, and ethanol is covalent so no ions (must give both points for 1 mark).
Worked solution
i. Magnesium sulfate (aq).
ii. Ions.
iii. Calcium bromide is solid so its ions are not free to move. Ethanol is covalent, so has no ions to carry charge.