Answer:
The answers are:
1) Latent heat of fusion
2) Heat is released
3) The process is endothermic
Explanation:
(1) The amount of energy required to freeze one kg of a substance is called latent heat of fusion.
(2) In a process, if heat is absorbed, the change in enthalpy for the substance is positive.
In a process, if heat is released, the change in enthalpy for the substance is negative.
The enthalpy of freezing for water is -6.02 kJ/mol. Heat is released as the enthalpy is negative.
(3) A positive value for enthalpy of vaporization indicates that the process is endothermic.
An exothermic process is one in which energy is released. The enthalpy for the process is negative.
An endothermic process is one which energy is absorbed. The enthalpy for the process is positive.
Answer:
The volume of this sample when the temperature is changed to 150 K and the pressure is changed to 160 kPa is 52.5 mL.
Explanation:
Boyle's law says that: "The volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure" and is expressed mathematically as:
P * V = k
where k is a constant.
Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is maintained at a constant pressure, by means of a constant of proportionality that is applied directly. So Charles's law is a law that mathematically says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:

Gay-Lussac's law states that the pressure of a fixed volume of a gas is directly proportional to its temperature. In other words, if the volume of a certain quantity of ideal gas remains constant, the quotient between pressure and temperature remains constant:

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

Considering an initial state 1 and a final state 2, it is satisfied:

In this case:
- P1: 240 kPa
- V1: 70 mL
- T1: 300 K
- P2: 160 kPa
- V2: ?
- T2: 150 K
Replacing:

Solving:

V2= 52.5 mL
<u><em>The volume of this sample when the temperature is changed to 150 K and the pressure is changed to 160 kPa is 52.5 mL.</em></u>
Answer:
Solids, liquids and gases all expand when heat is added
Explanation:
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. ...
Oxygen:
Atomic no. = 8(from periodic table)
⇒1s^2 2s^2 2p^4
But it is O^2-
There are 2 more electrons
=>1s^2 2s^2 2p^6
Voila!