Question

1. What is the final temperature of a solution initially at 22.0 celsius if 2.45 g of a solid is dropped into 34.5 g of the solution resulting in the reaction between the two that absorbs 1350 J of heat?

2. If a 31.25g piece of an unknown metal at 25 Celsius was added to 25.0 g of water at 100.0Celsius and the two equilibrated at 95.2 Celsius , what is the specific heat capacity of the metal?

3. In a coffee cup style calorimeter, 10.4 mL of an aqueous solution containing chemical A is mixed with 15.6 mL of an aqueous solution containing chemical B. If the two solutions start out at 23.50 Celsius and have a final temperature of 15.60 Celsius, what is q for the reaction that occurred between A and B? Assume no heat lost or gained by the calorimeter and the solutions have a density of 1.00 g/mL and specific heat capacity of 4.18 J/g Celsius

Answer 1

1.

initial temperature - 22.0 oC

mass = 2.45 g

mass of solution = 34.5 g

heat = 1350 J

Q = m Cp dT

1350 = 36.95 x 4.184 x (Tf - 22)

Tf = 30.7

final temperature = 30.7 oC

2. If a 31.25g piece of an unknown metal at 25 Celsius was added to 25.0 g of water at 100.0Celsius and the two equilibrated at 95.2 Celsius , what is the specific heat capacity of the metal?

heat loss by water = heat gain by metal

25 x 4.184 x (100 - 95.2) = 31.25 x cp x (95.2 - 25)

501.6 = 2193.75 x Cp

Cp = 0.229 J / g oC

specific heat of metal = 0.229 J / g oc