This is an example of a single-displacement reaction. In this type of reaction, one element replaces another element in a compound. In this case, zinc is replacing hydrogen in hydrochloric acid. The reaction can be represented by the following equation:

$$Zn + 2HCl → ZnCl_2 + H_2$$

The products of this reaction are zinc chloride and hydrogen gas. The reaction is exothermic, meaning that it releases heat. This is why the beaker gets warm.