In an effort to stay awake for an all-night study session, a student makes a cup

Question

In an effort to stay awake for an all-night study session, a student makes a cup of coffee by first placing a 204 W electric immersion heater in 0.325kg of water.

Part A

How much heat must be added to the water to raise its temperature from 18.8 Cto 77.4 C?

SubmitMy AnswersGive Up

Part B

How much time is required if all of the heater's power goes into heating the water?

In an effort to stay awake for an all-night study session, a student makes a cup of coffee by first placing a 204 W electric immersion heater in 0.325kg of water.

Part A

How much heat must be added to the water to raise its temperature from 18.8 Cto 77.4 C?

SubmitMy AnswersGive Up

Part B

How much time is required if all of the heater's power goes into heating the water?

Explanation / Answer

What is the unit of specific heat of water?.
It is very important information to solve this problem. (Ok...I take the unit of specific heat of water = J/kg.°C)

1)Q = m.c.T
.. = 0.325 x 4190 x (77.4 - 18.8)
.. = 0.325 x 4190 x 58.6
.. = 79798.55 Joule

m = mass, kg
c = specific heat of water, J/kg.°C
T = temperature diference, °C

2)Energy :
.................... W = Q = P.t
P = power, J/s
t = time, s
...............79798.55 Joule = 204 x t
............................ t =79798.55 /204
............................ t = 391.16 s
............................ t = 6.51 minutes

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

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