A pair of students found the temperature of 100. g of water to be 26.30°C. They

Question

A pair of students found the temperature of 100. g of water to be 26.30°C. They then dissolved 6.32 g of AgNO3 in the water. When the salt had dissolved, the temperature of the water was 24.29°C.

chemPad

- The temperature change would be twice as large.

- The temperature change would be three times as large.    

- The temperature change would be one-half as large.

- The temperature change would be one-third as large.

- The temperature change would be four times larger.

- The temperature change would be the same.

Explanation / Answer

A pair of students found the temperature of 100. g of water to be 26.30°C. They then dissolved 6.32 g of AgNO3 in the water. When the salt had dissolved, the temperature of the water was 24.29°C.

a) dT for water

dT = Tf-Ti =24.29-26.3 = -2.01 °C

b)

this must be ENDOTHERMIC, since it required heat from surroundings and dT is negative

c)

The water gave up energy to "heat" the dissolution

d)

Entropy typically increases for dissolution

e)

AgNO3(s) --> Ag+(aQ) + NO3-(aq)

f)

6.32 g of AgNo3

MW = 169.87

mol = mass/MW = 6.32/169.87 = 0.03720 moles of AgNO3, tehrefore 0.03720 mol of cation,Ag+; 0.03720 mol of anion

g)

dT must be 1/3 in change lower

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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