When reacted with $20 {\mathrm{cm}}^3$ of $1.0 \mathrm{mol} {\mathrm{dm}}^3$ hydrochloric acid, why does $5 \mathrm{g}$ of zinc powder react faster than a single $5 \mathrm{g}$ piece of zinc?

If left in the open, food usually goes bad because of oxidation or decomposition reactions. Which foods go bad quickly? What can we do to stop food going bad?

In places that have seasons which are very cold, some animals lower their body temperature. What is the advantage of this?

Make a list of other reactions that are very fast or very slow.

Convert the following rates into the units of $\mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{s}}^{-1}$:  $0.254 \mathrm{g}$ of ${\mathrm{I}}_2$, consumed in$1.00 \mathrm{h}$ in a reaction mixture of volume ${\text{1 dm}}^3$. $\left({\mathrm{A}}_{\mathrm{r}}\right[\mathrm{I}]= 127)$

Why it is essential to keep the temperature constant when measuring the progress of the reaction?

Draw a different set of apparatus that could be used to follow the course of reaction between calcium carbonate and hydrochloric acid.

What do you mean by the activation energy?

What do you mean by a catalyst?