The number of calories needed to raise the temperature of 32 g of water from 12 °C to 54 °C is
A)384 cal.
B)1.3 cal.
C)1300 cal.
D)1700 cal.
E)0.76 cal.

Question

Quizplus · Accepted Answer

The formula for calculating the amount of heat needed to increase the temperature of a substance is:

q = mcΔT

where:
q is the amount of heat (in calories)
m is the mass of the substance (in grams)
c is its specific heat capacity (in cal/g°C)
ΔT is the change in temperature (in °C)

In this problem, we have:

m = 32 g
ΔT = 54 °C - 12 °C = 42 °C
c = 1 cal/g°C (this is the specific heat capacity of water)

Plugging in these values, we get:

q = (32 g)(1 cal/g°C)(42 °C) = 1344 cal

However, we should round this answer to the nearest hundred, since the question only gives us four significant figures. So the answer is:

1300 cal

Therefore, the best choice is C.

The Number of Calories Needed to Raise the Temperature of 32