Methane gas released from waste water treatment plants can be used as a source of fuel. Which chemical equation represents combustion of methane to produce heat energy?

Which of the following is an example of simple displacement reaction?

Given below is the balanced chemical equation for the thermal decomposition of lead nitrate.

$2\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2\to 2\mathrm{PbO}+4{\mathrm{NO}}_2+{\mathrm{O}}_2$

Which of the following information does the coefficients of $\mathrm{PbO}$ and ${\mathrm{NO}}_2$ in the equation ($2$ and $4$ respectively) tell us?

The diagram below shows the set-up in which the electrolysis of water takes place.

What type of reaction takes place?

The diagram below shows the set-up in which the electrolysis of water takes place.

Explain why this is an example of an endothermic reaction?

The diagram below shows the set-up in which the electrolysis of water takes place.

The test tube containing hydrogen is removed carefully from the apparatus. A lit match stick is brought near the mouth of this test tube. The gas burns with an explosive "pop" sound.

Write a balanced chemical equation for the above electrolysis reaction and indicate whether energy is absorbed or released.

Eight identical, iron blocks are placed on the ground in the two arrangements X and Y as shown below. The block arrangements are kept moist by sprinkling water every few hours.

Which of the arrangements is likely to gather more rust after ten days? justify your answer.

The following chemical equation does not represent a chemical reaction that can take place.
$3 \mathrm{Fe}\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)$

State what needs to be changed in the equation above for it to represent the correct reaction between $\mathrm{Fe}$ and ${\mathrm{H}}_2\mathrm{O}$.