While studying for this quiz you realize that you still have 100 g of lukewarm coffee at 40$\degree$C left in a paper cup. When you pour 20 g of boiling water into the cup, the temperature of the resulting coffee-like mixture will be now
A) 50$\degree$C.
B) 60$\degree$C.
C) 67$\degree$C.
D) 70$\degree$C.
E) 80$\degree$C.

Question

Quizplus · Accepted Answer

The final temperature can be calculated using the principle of conservation of energy. The heat lost by the boiling water will equal the heat gained by the coffee. Using the formula $m_1c(T_f - T_1) = m_2c(T_2 - T_f)$, where $m_1$ and $m_2$ are the masses, $T_1$ and $T_2$ are the initial temperatures, and $T_f$ is the final temperature, we find that the final temperature is 50°C.

While Studying for This Quiz You Realize That You Still °\degree°

While Studying for This Quiz You Realize That You Still $\degree$