Question

Heat of combustion is defined as the amount of heat released when a known mass of a substance is burned and can be measured in joules per gram. At the start of the activity, the mass of the candle and the mass of the water are measured. The starting temperature of the water is 5.0°C, and the air temperature in the room is 22.0°C. The candle is lit, and the water is stirred with a stirring rod. Several minutes later, the candle is extinguished, and the student measures the temperature of the water in the can. When the candle is cool, the student measures the final mass of the candle. Lab activity results are shown in the table below.37. State the direction of the heat flow between the air and the water in the can before the candle is lit.

Answer 1

The direction of heat flow between the air and the water in the can before the candle is lit is from the air to the water because the air is at a higher temperature than the water.

Heat always flows from a hotter object to a colder object. Heat is a form of energy that is transferred from one object to another due to a difference in temperature. The hotter object has more thermal energy than the colder object, and this excess energy is transferred from the hotter object to the colder object until they reach the same temperature.

Thermal energy is random. The atoms and molecules in a hotter object are moving faster and more randomly than those in a colder object. This random motion causes the atoms and molecules to collide with each other and exchange energy. When a hot atom or molecule collides with a cold atom or molecule, it transfers some of its thermal energy to the cold atom or molecule.