Similar question to http://www.jiskha.com/display.cgi?id=1474753951
"If that 22.33g sample of calcium chloride was dissolved in 1000.0g of water, with both substances originally at 25.0C, what would be the final temperature of the solution be? Assume no loss of heat to the surroundings and that the entire solution has a specific heat capacity of 4.184J/gC."
CaCl2(s) -> Ca(aq) + 2Cl(aq) ΔH_rxn = +198.0 KJ
*The amount of heat that would be absorbed for 22.33g of CaCl2 is +40.2KJ.
Is the heat absorbed is related to the question above? From that other question forum, the person mentioned "176kj=1000*4.18*deltaTemp". Where did they get the 176KJ? I'm very confused on this question, thank you.
To determine the final temperature of the solution, we need to use the principle of conservation of energy, specifically the heat transfer equation. This equation is:
q = m × c × ΔT
Where:
q is the heat transferred (in joules),
m is the mass of the substance (in grams),
c is the specific heat capacity of the substance (in J/g°C), and
ΔT is the change in temperature (in °C).
In this case, we are considering the dissolution of calcium chloride in water. The heat absorbed by the solution will be equal to the heat released by the calcium chloride.
The heat released by the calcium chloride is given as +40.2 kJ, which needs to be converted to joules by multiplying by 1000 (since 1 kJ = 1000 J).
40.2 kJ × 1000 J/kJ = 40200 J
Now, let's use the heat transfer equation to find the final temperature of the solution.
40200 J = (22.33 g + 1000.0 g) × 4.184 J/g°C × ΔT
We need to solve for ΔT, the change in temperature. First, sum the masses of calcium chloride and water:
22.33 g + 1000.0 g = 1022.33 g
Now, substitute the values into the equation:
40200 J = 1022.33 g × 4.184 J/g°C × ΔT
Simplifying gives:
40200 J = 4275.09752 g°C × ΔT
Divide both sides by 4275.09752 g°C to isolate ΔT:
40200 J ÷ 4275.09752 g°C = ΔT
This gives us the change in temperature, ΔT. Now, we can calculate the final temperature by adding ΔT to the initial temperature of the water (25.0°C):
Final temperature = 25.0°C + ΔT
Now, let's address where the 176 kJ mentioned in the other forum post came from.
It seems that the person in the forum made a mistake in their calculation. The correct value to use is 40.2 kJ, not 176 kJ. So, there is no need to consider the 176 kJ value mentioned there.
To summarize, to find the final temperature of the solution, you need to use the heat transfer equation and apply the principle of energy conservation. The heat absorbed by the solution is equal to the heat released by the calcium chloride. Convert the given heat value into joules and substitute the known values into the equation. Perform the necessary calculations to find ΔT and then add it to the initial temperature to obtain the final temperature of the solution.