Calculate the theoretical amount of CaCl2 that would be required to change the temperature of 50ml of water from room temperature 20C to 45C? Remember heat loss during the dissolution is equal to the heat capacity of water. this value is 4.184. you assume that the density of the water is 1g/ml.
50 mL of Water
Ti = 20C
Tf = 45C
d = 1.00 g/mL
C = 4.184 J/g * C
50 mL * 1.00g/mL = 50 g
Delta T = 45-20 = 25 C
q = m * C * T
= (50) (4.184) (25)
= - 5230 J
-5230/-82800 = 0.061 mol
Molar mass of CaCl2 = 110.98 g/mol
0.061 mol * 110.98 g/mol = 6.77 g
what does -82800 mean?
In response to susan, the -82800 is the heat of solution for CaCl2 in joules.
To calculate the theoretical amount of CaCl2 required to change the temperature of water, we can use the formula:
Q = m * c * ΔT
where Q is the heat energy, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature.
In this case, we have the following values:
- m (mass of water) = 50 ml = 50 g (since the density of water is 1 g/ml)
- c (specific heat capacity of water) = 4.184 J/g·°C (given)
- Initial temperature (T1) = 20°C
- Final temperature (T2) = 45°C
To find the heat energy (Q), we use the equation:
Q = m * c * ΔT
First, find the change in temperature (ΔT):
ΔT = T2 - T1
ΔT = 45°C - 20°C
ΔT = 25°C
Now we can calculate the heat energy (Q):
Q = m * c * ΔT
Q = 50 g * 4.184 J/g·°C * 25°C
Q = 5230 J
Next, we need to consider that the heat loss during the dissolution of CaCl2 is equal to the heat capacity of water, which is 4.184 J/g·°C.
Therefore, the theoretical amount of CaCl2 required to provide 5230 J of heat energy is:
Amount of CaCl2 = Q / Heat capacity of water
Amount of CaCl2 = 5230 J / 4.184 J/g·°C
Amount of CaCl2 = 1250 g
Hence, the theoretical amount of CaCl2 required to change the temperature of 50 ml of water from 20°C to 45°C is 1250 grams.