Question

A calorimeter is a tool for measuring the amount of heat involved in a change or chemical reaction. The working principle of the calorimeter is based on the principle of black which reads "the heat released by a hot object, the same as the heat received by a cold object".

a. One practitioner puts 75 ml of 5 ° C water into calorimeter A, followed by adding 75 ml of boiling water. At the same time another student put 75 ml of 5 ° C water into calorimeter B, followed by adding 75 ml of water at 60 ° C. Explain your opinion about the differences in the specific heating values obtained in the 2 experiments.

b. 50 ml (= 50 grams) 1 M HCl solution at 27 ° C mixed with 50 ml (= 50 grams) 1 M NaOH solution at 27 ° C in a simple calorimeter. The temperature of the mixture rises to 33.5 ° C. If the heat of the solution = heat of the water = 4.18 J / g.K. Determine the enthalpy change!

*sorry that's all i got

Answer 1

The amount of exchange of heat between the two forms of matter in the calorimeter is given by the equation,

(a) In the calorimeter A, the two forms of matter are water at 100 deg C added to water at 5 deg C

In the calorimeter B, the two forms of matter are water at 60 deg C added to water at 5 deg C.

In both cases, Q will vary according to the value of .

In the first case, since the added water is at 100 deg C, will be higher. Let's say the temperature of water in the calorimeter changes from 5 deg C to 85 deg C. So =85-5=80 deg C.

So .

Therefore, in the above two experiments, the specific heating values will be different.

(b)

In the second case, since the added water is at 60 deg C, will be lower. Let's say the temperature of water in the calorimeter changes from 5 deg C to 45 deg C. So =45-5=40 deg C.

So .

The amount of heat exchange can also be expressed as

where is the enthalpy change.

Therefore,

So the enthalpy change is given by 27.17J/g