Answer:
Option A: none
Explanation:
Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.
From the question, the parameters given are; The heat of vaporization of nitrogen= 48 cal/g and that of water is 80 cal/g.
Using the formulae; Specific heat capacity,c= Q/ m× ∆T,----------–-----------------------------------------------------
STEP ONE: We will have to calculate all the energy numbers; 77k is approximately the boiling point of Nitrogen.
Energy required to decrease water from 15°C to 0°C = E(1).
0.1×10^3 g× 48 cal/gram..
= 4800 cal
Energy require to vaporize Nitrogen=E(2).
= 80 cal per gram×0.15(15-0)
= 180 cal
Energy required to decrease water from 15°C to 0°C is higher than that of the energy to vaporize Nitrogen, N2.
STEP 2: 180/4800× 15 = 0.5625
Therefore; 15-0.5625 =14.43
Answer= 14.43gC
Answer:
(a). none
Explanation:
Heat gained by nitrogen = Heat lost by water
Q₁ = Q₂ + Q₃................... Equation 1
Where Q₁ = heat required for nitrogen to vaporize, Q₂ = heat required for to change temperature from 15 °C to 0 °C, Q₃ = heat required for water to vaporize.
Q₁ = m₁l₁ .................... Equation 2
Q₂ =cm₂(T₁-T₂) .............. Equation 3
Q₃ = m₃l₂................ Equation 4
Note: For the water to freeze, Q₁ > Q₂
Where m₁ = mass of nitrogen, m₂ = mass of water in liquid state, m₃ = mass of water that freezes, l₁ = heat of vaporization of nitrogen, l₂ = heat of vaporization of water, c = specific heat capacity of water, T₁ = initial temperature of water, T₂ = Final Temperature of water( Temperature at freezing point)
Given: m₁ = 100 g, m₂ = 500 g, T₁ = 15 °C, T₂ = 0 °C, l₁ = 48 cal/g, 80 cal/g
Constant: c = 1.00 cal/g.k
Substituting these values into equation 2, 3 and equation 4
Q₁ = 100 × 48 = 4800 Cal.
Q₂ = 1 × 500 × (15-0)
Q₂ = 7500 cal
Q₃ = m₃(80) = 80m₃ Cal
Substituting the values of Q₁, Q₂ and Q₃ into Equation 1
4800 = 7500 + 80m₃
Collecting like terms
80m₃ = 4800 - 7500
m₃ = -2700/80
m₃ = no ice formed, Because the mass of a substance can not be negative.
Therefore, The nitrogen evaporates but does not cause any change in temperature.
The right option is (a) none
