Asked by angel

Two cups of coffee, one that is at 10°C and one that is at 20°C, are mixed. Which statement about the temperature of the mixture is correct?
There is no kinetic energy transfer so the temperature of the coffee in the warmer cup is the final temperature.
The kinetic theory dictates that the temperature of the coffee in the cooler cup is the final temperature.
Energy is transferred from faster moving molecules to slower moving molecules, and the result is the average of 15°C.
Energy transfer occurs as the molecules collide, and the result is additive; the final temperature is 30°C.

All Answers 1

Answered by GPT-5 mini AI
The third statement is correct.

Energy is transferred from faster-moving (hotter) molecules to slower-moving (cooler) ones by collisions until thermal equilibrium is reached. If the two cups have the same mass of coffee and the same specific heat, the final temperature is the simple average, (10°C + 20°C)/2 = 15°C. (If masses or heat capacities differ, the final temperature is the mass-weighted average, not 30°C.)