Question

A hot rock ejected from a volcano’s lava fountain cools from 1100º C to 40.0º C, and its entropy decreases by 950 J/K. How much heat transfer occurs from the rock?

a) 20,000 J
b) 25,000 J
c) 30,000 J
d) 35,000 J

Answer 1

The heat transfer from the rock is approximately 1,000,000 J.

Step-by-step explanation:

To determine the amount of heat transfer that occurs from the rock, we can use the equation: ΔS = Q/T, where

ΔS is the change in entropy,

Q is the heat transfer, and

T is the temperature in Kelvin.

Given that the entropy decreases by 950 J/K and the temperature changes from 1100º C to 40.0º C, we can convert these temperatures to Kelvin (1373 K and 313 K, respectively) and rearrange the equation to solve for Q:

Q = ΔS * T = 950 J/K * (1373 K - 313 K) = 950 J/K * 1060 K = 1,004,000 J = 1,004,000 J.

Therefore, the amount of heat transfer from the rock is 1,004,000 J, which is approximately equal to 1,000,000 J.