Question

ΔF heat of solution for calcium chloride is -82.9kj/mol. if 25 grams of calcium chloride is dissolved in 100 g of water initially at 20 degrees c what is the final temperature?

Answer 1

The final temperature is 0.75 °C.

Step-by-step explanation:

To find the final temperature, we can use the equation:

q = m*c*ΔT

where q is the heat absorbed or released, m is the mass of the solution, c is the specific heat capacity, and ΔT is the temperature change. In this case, the mass of the solution is 100 grams of water, and the change in temperature is the final temperature minus the initial temperature. We can rearrange the equation to solve for the final temperature:

Final temperature = (q / (m * c)) + initial temperature

Using the given values, the heat, q, can be calculated by converting the heat of the solution from kJ to J, and multiplying by the moles of calcium chloride:

q = -82.9 kJ/mol * (25 grams / (110.98 g/mol)) * 1000 J/1 kJ = -1.88 x 10^4 J

Now we can substitute the values into the equation to find the final temperature:

Final temperature = (-1.88 x 10^4 J / (100 grams * 4.18 J/g °C)) + 20 °C = 0.75 °C