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.
Explanation:
This graph shows that an increase in altitude causes a relative decrease in boiling point temperatures. The two variables, it can be said, are inversely proportional.
This is because, with an increase in altitude, there is a proportionate decrease in air pressure. This means the vapor pressure of the fluid becomes strong enough, at a relatively lower temperature, to overcome the air pressure and for the liquid to boil.
This is why water can even boil without inputting heat into it but rather by just reducing the ambient air pressure.
Answer:
1(a) N = 3
(b) N = 0
(c) N = 5
(d) N = -2
(2) Molecular formula for benzene is C6H6
Explanation:
1(a) N02 1-
N + (2×-2) = -1
N-4 = -1
N = -1+4 = 3
(b) N2
2(N) = 0
N = 0/2 = 0
(c) NO2Cl
N + ( 2×-2) + (-1) = 0
N - 4 - 1 = 0
N - 5 = 0
N = 0+5 = 5
(d) N2H4
2(N) + (4×1) = 0
2N + 4 = 0
2N = 0 - 4 = -4
N = -4/2 = -2
(2) Molcular mass of benzene = 78g/mole = (6×12g of carbon) + (6×1g of hydrogen) = 72+6 = 78g/mole
Therefore, molecular formula for benzene is C6H6
[H+][OH-] = 1x10-14 = Kw (Memorize this relationship)
(2.70x10-2)[OH-] = 1x10-14
[OH-] = 1x10-14/2.70x10-2
[OH-] = 3.70x10-13 M (assuming you ignore the autoionization of H2O)
I hope my photo helps. since oxygen goes from a charge of 0 to -2, it gains electrons because electrons have a negative charge. nitrogen goes from 0 to +2 meaning that it is losing electrons to make it a positive charge.
