Determine the enthalpy for the addition of Mg to HCl for this trial. Assume the specific heat capacity is 4.184 J/g degrees Celsius.
Givens:
mass of Mg = 0.150 g
moles of Mg = 0.00617 mol
mass of HCl= 45.0 g
temperature of calorimeter= 21.5 degrees celsius
max temp. of mixture = 35.6 degrees celsius
mass of calorimeter, Mg & HCl after reaction: 169.620 g
I know the formula is qrxn = m x c x change in T + C cal x change inT cal
,but I'm unsure where the values go
To determine the enthalpy for the addition of Mg to HCl, you can use the formula for heat transfer, which is q = m × c × ΔT, where q is the heat transfer, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.
In this case, you need to consider two temperature changes: the change in temperature of the water in the calorimeter (calorimeter's temperature change, ΔTcal), and the change in temperature of the mixture of Mg and HCl (reaction temperature change, ΔTrxn).
The heat transfer for the calorimeter is given by qcal = Ccal × ΔTcal, where Ccal is the heat capacity of the calorimeter.
Now, let's calculate the enthalpy for the addition of Mg to HCl using the given values:
1. Calculate qrxn (heat transfer for the reaction):
qrxn = m × c × ΔTrxn
Given:
mass of Mg (m) = 0.150 g
specific heat capacity (c) = 4.184 J/g°C
ΔTrxn = max temp. of mixture - temperature of calorimeter
= 35.6°C - 21.5°C
Substitute the values into the formula:
qrxn = 0.150 g × 4.184 J/g°C × (35.6°C - 21.5°C)
2. Calculate qcal (heat transfer for the calorimeter):
qcal = Ccal × ΔTcal
Given:
mass of calorimeter, Mg & HCl after reaction = 169.620 g
mass of HCl = 45.0 g
mass of water in the calorimeter = mass of calorimeter, Mg & HCl after reaction - mass of HCl
Substitute the value into the formula:
mass of water in the calorimeter = 169.620 g - 45.0 g
qcal = (mass of water in the calorimeter) × c × ΔTcal
Finally, to determine the enthalpy of the reaction, use the equation ΔH = qrxn + qcal. Substitute the calculated values of qrxn and qcal, and you will have the enthalpy for the addition of Mg to HCl for this trial.