Adding 1.530x10^3 J of electrical energy to a constant-pressure calorimeter changes the water temperature from 20.50C to 21.85C. When 1.75g of a solid salt is dissolved in the water, the temperature falls from 21.85C to 21.44C. Find the value of qp for the solution process.
1530 = Ccal*delta T
1530 = Ccal*(21.85-20.5)
Ccal = ?
q = Ccal*delta T salt.
q = Ccal from above x (delta T)
To find the value of qp for the solution process, we need to consider the heat gained or lost by the system.
Let's break it down into two steps:
Step 1: The electrical energy added to the calorimeter
In this step, energy is added to the system by the electrical source. The temperature of the water increases from 20.50°C to 21.85°C.
We can use the formula:
q = mcΔT
where:
q is the heat gained or lost
m is the mass of the water
c is the specific heat capacity of water
ΔT is the change in temperature
Given:
Specific heat capacity of water, c = 4.18 J/g°C
Mass of the water, m = unknown (we will solve for it)
q = mcΔT
Substituting the given values:
1.530x10^3 J = m * 4.18 J/g°C * (21.85°C - 20.50°C)
Simplifying the equation, we get:
1.530x10^3 J = m * 4.18 J/g°C * 1.35°C
Dividing both sides by (4.18 J/g°C * 1.35°C):
m = (1.530x10^3 J) / (4.18 J/g°C * 1.35°C)
Calculate the right-hand side of the equation to find the mass of water.
Step 2: The solution process
In this step, the temperature of the water decreases from 21.85°C to 21.44°C when 1.75g of a solid salt is dissolved.
To find the heat gained or lost in this case, we can again use the formula: q = mcΔT
Given:
Specific heat capacity of water, c = 4.18 J/g°C
Mass of the water, m = found in Step 1 (in grams)
Change in temperature, ΔT = (21.44°C - 21.85°C)
q = mcΔT
Substituting the given values:
q = (mass of water) * 4.18 J/g°C * (-0.41°C)
This gives us the heat lost during the solution process.
The value of qp for the solution process will be the sum of the heat gained in step 1 and the heat lost in step 2.
Hope this helps!