Please help me with this question:
Calculate the theoretical yield amount of CaCl2 that would be required to change the temp of 50ml of water from room temp 20degree to 45 degrees. Heat Capacity H20 is 4.184 Jg^-1deg^-1 and density is 1g/mL.
I've already calculated: Q=mc delta T
(50g)(4.184J/g^-1)(45-20deg)
=5230 J
so then the Q of CaCl2 is -5230 J. What do I do from here I am so confused!
Please help
See your other post above.
To calculate the theoretical yield amount of CaCl2 required to change the temperature of water, you need to use the equation:
Q = mc∆T
where Q is the amount of heat energy transferred, m is the mass of the substance being heated (in this case, water), c is the specific heat capacity of water, and ∆T is the change in temperature.
You have already correctly calculated the amount of heat energy, Q, as 5230 J.
To find the mass of CaCl2 required, you need to rearrange the equation and solve for the mass:
m = Q / (c∆T)
Where:
- m is the mass of CaCl2 in grams
- Q is the amount of heat energy in joules
- c is the specific heat capacity of CaCl2
- ∆T is the change in temperature
The specific heat capacity of CaCl2 is not provided in the question. However, assuming that CaCl2 has the same specific heat capacity as water, which is 4.184 Jg^-1deg^-1, you can substitute the known values into the equation:
m = 5230 J / (4.184 J/g^-1deg^-1 * ∆T)
Since ∆T is given as 45 - 20 = 25 degrees Celsius, you can plug in the values:
m = 5230 J / (4.184 J/g^-1deg^-1 * 25 deg)
Simplifying the equation:
m = 5230 J / (104.6 J/g^-1)
m ≈ 50 g
So, the theoretical yield amount of CaCl2 required to change the temperature of 50 mL of water from 20 degrees Celsius to 45 degrees Celsius is approximately 50 grams.