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Heat Quiz
1. How much heat is needed to warm 30.0 g of
water from 20.0 oC to 50.0 oC ?
Cp = 4.18 J / go C
2. It takes 27.6 joules to heat 20.0 g of mercury
from 10.0 oC to 20.0 oC.
Calculate the specific heat of mercury.
3. The specific heat of aluminum is 0.900 J/g oC.
If 20.0 g of aluminum at 10.oC absorbs 126 J
of heat, what is its final temperature?
Heat = mass (g) x ∆T (oC) x Cp (J / g oC)
1.
Heat = 30.0 g x 30.0 oC x 4.18 J / goC
= 3762 J = 3760 J (3.76 kJ )
2.
27.6 J = 20.0 g x 10.0 oC x Cp
___27.6 J ___ =
20.0 g x 10.0 oC
Cp
= 0.138 J / g oC
Heat = mass (g) x ∆T (oC) x Cp (J / g oC)
3.
126 J = 20.0 g x ∆T x 0.900 J / g oC
_______126 J_______ = ∆T = 7.00 oC
20.0 g x 0.900 J / g oC
Final temp. = 10. oC + 7 oC = 17 oC

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