Question

which formula would you use to calculate the heat absorbed by a 25 g sample of water as it warms from 10 °c to 30 °c?
$q = mcdotdelta h_{vap}$
$q = mcdot ccdotdelta t$
$q = mcdotdelta h_{fus}$
$q = mdelta t$

2 multiple choice 1 point
what does the \specific heat capacity\ (c) of a substance represent?
c) the amount of heat required to raise the temperature of one gram of the substance by one degree celsius.
a) the amount of heat required to melt one gram of the substance.
b) the amount of heat required to vaporize one gram of the substance.
d) the total heat contained within one gram of the substance.

3 multiple choice 1 point
which of the following phase changes is an exothermic process?
b) ice melting in a glass of water
d) a solid block of dry ice turning into a gas
a) evaporation of sweat from your skin
c) water vapor turning into frost on a cold morning

Explanation:

Step1: Identify heat - absorption formula

When calculating heat absorbed during a temperature change of a substance without phase - change, the formula $q = m\cdot c\cdot\Delta T$ is used. Here, $q$ is the heat absorbed or released, $m$ is the mass of the substance, $c$ is the specific heat capacity, and $\Delta T$ is the change in temperature.

Step2: Define specific heat capacity

The specific heat capacity ($c$) of a substance is the amount of heat required to raise the temperature of one gram of the substance by one degree Celsius.

Step3: Identify exothermic process

An exothermic process is one in which heat is released. When water vapor turns into frost (deposition), heat is released. Melting, evaporation, and sublimation (dry - ice turning into gas) are endothermic processes.

Answer:

1. B. $q = m\cdot c\cdot\Delta T$
2. c) The amount of heat required to raise the temperature of one gram of the substance by one degree Celsius.
3. c) Water vapor turning into frost on a cold morning