2. A calorimeter is to be calibrated: 51.203 g of water at 55.2°C is added to a

Question

2. A calorimeter is to be calibrated: 51.203 g of water at 55.2°C is added to a calorimeter contain- ing 49.783 g of water at 23.5°C. After stirring and waiting for the system to equilibrate, the final temperature reached is 36.7°C. Calculate the calorimeter constant. Using the same calorimeter from question 2, calculate the amount of hear evolved when 50.00 mL of 0.400 M copper(II) sulfate solution at 23.35°C is mixed with 50.00 mL of 0.600 M NaOH solu- tion at same temperature. After the reaction occurs, the final temperature of the resulting mix ture is measured to be 25.23°C. The density of the final solution is 1.02 g/mL. Assume the specific heat of solution is the same as pure water, 4.184 J/g°C 3.

Explanation / Answer

Ans 2

Energy balance

Heat released by hot water = heat absorbed by cold water + heat absorbed by calorimeter

mw x Cpw x (T1 - T) = mc x Cpw x (T - T2) + C x (T - T2)

51.203 g x 4.184 J/gC x (55.2 - 36.7) C = 49.783 g x 4.184 J/gC x ( 36.7 - 23.5) C + Cc x (36.7 - 23.5) C

3963.317 J = 2749.455 J + Cc x 13.2

Cc = 1213.862/13.2 = 91.96 J/°C

Ans 3

Heat evolved = mass of solution x Cp x (T2-T1)

= (50 + 50) mL x 1.02g/mL x 4.184 J/gC x (25.23 - 23.35)C

= 802.32 J

= 0.802 kJ

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.