Answer: Statements (A), and (C) are correct.
Explanation:
The statements that are true are as follows.
- Particles in a liquid need to move more slowly in order to freeze.
When a liquid freezes the molecules get attracted towards each other. This attraction of particles occurs slowly. Hence, this statement is true.
- Attractive forces between the particles in a liquid are broken when a liquid boils.
When temperature is raised, the molecules in a liquid gains kinetic energy and start to move quickly in random directions. As a result, liquid state changes to gaseous state. Hence, this statement is true.
If the attractive force between gas molecules have to be increased, they should be moving slower instead because moving faster does not help attracting molecules together.
Hence, the statement particles in gas move fast enough to make more attractive forces when the gas condenses is not true.
Copper heat capacity would be <span>0.385J/C*gram which means it needs 0.385 Joule of energy to increase 1 gram of copper temperature by 1 Celcius. The calculation would be:
energy= heat capacity *mass * temperature difference
energy= </span>0.385J/C*gram * 6g * (90-20)
<span>energy= 161.7J
</span>
Explanation:
Boiling is defined as a process in which vapor pressure of a liquid substance becomes equal to the atmospheric pressure.
During this change liquid and vapors remain in equilibrium and the equation for this change is as follows.

Therefore, when boiling takes place then average kinetic energy of particles in liquid phase equals to the average kinetic energy of particles in vapor phase.
Hence, we can increase the kinetic energy of particles in liquid phase by increasing the temperature because kinetic energy is directly proportional to temperature as follows.
K.E = 