<span>Melting is an endothermic process (i.e. it absorbs heat), whereas freezing is an exothermic process (i.e. it releases heat, or can be thought of, albeit incorrectly from a thermodynamics standpoint, as "absorbing cold"). The standard enthalpy of fusion of water can be used for both scenarios, but standard enthalpy is in units of energy/mass, so 10 times as much energy will be absorbed in the former scenario (melting 10 kg of ice) than what will be absorbed in the latter scenario (freezing 1 kg of water). For both processes, assuming the water is pure and at standard atmospheric pressure, and the entire mass remains at thermal equilibrium, the temperature of both the solid and the liquid will remain at precisely 0 degrees Celsius (273 K) for the duration of the phase change.</span>
The independent variable would be the variable in the research that is being manipulated by the researcher. In this case, it would be amount of food as it is what is being manipulated and changed in the research design. The dependent variable would be the variable that is being studied so, for this case, it would be the weight gain of the mice. The constants are the factors that might affect the dependent variable but is held constant or the same by the researcher throughout the experiment. These are the size of cage, amount of water, amount of sunlight, temperature and the exercise wheel.
<span>The molar mass of the compound is 122 g. </span>
Answer:
The answer is A (number 1)
