a race car sits at the starting line on a racetrack. when the race car starts the cars tires expert a force on the track. according to newton's law of motion what prevents the racecar from sinking into the track

Which best represents the law of conservation of mass ?

Could someone me find the answer to this problem.

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.