Explain the following term : Frequency of collision

Why does increasing pressure in a chemical reaction involving gases increase the rate of reaction?

Why does decrease a decrease in temperature lead to a decrease in the rate of a chemical reaction?

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?