A cup that contains 5 ounces of water absorbs 1080J of energy from a heater. If
ID: 1661062 • Letter: A
Question
A cup that contains 5 ounces of water absorbs 1080J of energy from a heater. If the intial temperature of the water was 20 C, what is the final temperature of the water?
Answer sheet says final temperature (T2) is 21.8 C
but I am unsure how. My Calculations are assume it includes the Cp of Water=4180J/kg*C
(0.1417475kg)(4180J/kg*c)(20 C) = 1080J x T2
which gives 11850.091J / 1080 J = 10.97 C
Final answer is 10.97C but 10.97 C=/= Correct answer of 21.8 C. Seeking guidance on what step I missed and the thought process behind the answer.
Explanation / Answer
Here, 1 ounce = 28.35 gm
Mass (m)= 5 x 28.35= 141.75 gm
Specific heat (c) = 4.18 J/ gm- degree cel.
Heat (Q) = mc (T2 - T1)
T2 - T1 = Q/mc
T2 = T1 + Q/mc
= 20 + 1080/141.75*4.18
= 20 + 1.8= 21.8 C
T2 = 21.8 C