The ratio of substance X to substance Y in a solution is measured in two separate trials.The concentrations,ratios of X/Y,and log(X/Y)are presented in this table. $\begin{array}{|c|c|c|c|c|}
\hline \text { Trial } & \begin{array}{c}
\text { Concentratio } \
\mathbf{n ~ o f ~ X ~}
\end{array} & \begin{array}{c}
\text { Concentratio } \
\mathbf{n} \text { of Y }
\end{array} & \text { Ratio X/Y } & \log (\mathbf{X} / \mathbf{Y}) \
\hline 1 & 20 & 10 & 2 & 0.301 \
\hline 2 & 10 & 20 & 0.5 & ? \
\hline
\end{array}$
What is the log of X/Y from trial 2?

Question

Quizplus · Accepted Answer

The log of a fraction (less than 1) is negative, and since the ratio X/Y in trial 2 is the reciprocal of the ratio in trial 1 (0.5 = 1/2), the log will be the negative of the log from trial 1, which is -0.301.

The Ratio of Substance X to Substance Y in a Solution