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A student using the Joule heat apparatus records the following data. Mass of alu

ID: 1534248 • Letter: A

Question

A student using the Joule heat apparatus records the following data. Mass of aluminum cup: 80.0 grams Mass of water: 375 grams Voltage: 6.0 V Current: 1.5 A degree Time: 17 minutes, 0 seconds Initial Water Temp: 19.2 degree C Final Water Temp: 24.7 degree C Specific heat of water: 1 calorie/g degree C Specific heat of aluminum: 0.215 calorie/g degree C How much electrical energy was supplied by the heating coil (in Joules)? How much heat was gained by the water (in calories)? How much heat was gained by the cup (in calories)? What is the total heat gained by the water and the cup (in calories)? Setting the electrical energy equal to the heat, solve for how many Joules are equivalent to one calorie.

Explanation / Answer

1.

V = Voltage = 6 volts

i = current = 1.5 A

t = time = 17 min = 17 x 60 = 1020 sec

E = electrical energy supplied = V i t = 6 x 1.5 x 1020 = 9180 J

2.

heat gained by water

Qw = mw cw (Tf - Ti) = (375) (1) (24.7 - 19.2) = 2062.5 cal

3.

heat gained by cup

Qc = mc cc (Tf - Ti) = (80) (0.215) (24.7 - 19.2) = 94.6 cal

4.

Total heat gained = Q = Qw + Qc = 2062.5 + 94.6 = 2157.1 cal

5.

9180 J = 2157.1 cal

1 cal = 4.25 J