A small electric vehicle is powered by rechargeable lead-acid car batteries - VCE - SSCE Chemistry - Question 4 - 2004 - Paper 1

To calculate the energy used, we use the formula:

$\text{Energy} = \text{Power} \times \text{Time}$

Given that the power consumption is 1.0 kJ/s and the travelling time is 2.5 hours, we first convert the time into seconds:

$2.5 \text{ hours} = 2.5 \times 3600 = 9000 \text{ seconds}$

Now, substituting the values:

$\text{Energy} = 1.0 \text{ kJ/s} \times 9000 \text{ s} = 9000 \text{ kJ}$

$2\text{PbSO}_4(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{Pb(s)} + \text{PbO}_2(s) + 2\text{H}_2\text{SO}_4(aq)$

The voltage required to recharge the battery must be greater than 12 V, so a voltage of at least 12.1 V should be applied to ensure effective recharging.