I need help with this question it's science

The reaction q+r2=r2q is found to be first order in r2 and

In the reaction between a crushed antacid tablet and vinegar what gas is emitted

3. how much energy in joules is required to evaporate .0005 kg of liquid ammonia to vapor at the same temperature? 4. how much energy ( in megajoules ) is given up by .75 kg of water at 0c when it freezes to form ice at 0c? 5. explain how heat works between and at critical temperatures?