7 A lead
B Gold
Csilver
8 Afeathrr
B water
C silver
Energy can be conserved by efficient energy use.
Answer: Option A
<u>Explanation:</u>
Energy can be transferred from one form to another, but it cannot be destroyed or created. So it can be conserved if efficiently used. Thus efficient usage of energy lead to conservation of energy. Due to conservation of energy, the forces can be renewable and non-renewable.
So, we should know how the input energy can be completely converted to another form of energy leading to efficient usage of energy without any loss. As if there is no loss, input energy will be equal to output energy leading to 100% efficiency.
Explanation:
Relation between pressure, latent heat of fusion, and change in volume is as follows.
Also, 
where, 
is the difference in specific volumes.
Hence, 
As, 
= 22.0 J/mol K
And, 
...... (1)
where, 
= density of water
= density of ice
M = molar mass of water = 
Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.
= 
= 
Therefore, calculate the required pressure as follows.
= 
or, = 145 bar/K
Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP = 
= 681.5 bar
Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.
Answer:
Explanation:
Given the details, we can say that
Pure methanol is a volatile solvent as the vapour pressure has a high value. This means that methanol - methanol intermolecular forces are weak in comparisson to water - water forces. When having about 30% of water in a methanol mixture, the mixture Pv decreased, showing that it is not a volatile mixture, so then there are strong intermolecular interactions between methanol - water, part of it due to the hydrogen bonds.
