Question

pre - lab quiz - lab 3: osmosis and plasmolysis sc/biol 1000 a, b, c & d - biology i (fall 2025) (all labs) pre - lab quiz - lab 3: osmosis and plasmolysis time left 1:23:47 question 2 you are given a 3 m stock solution of kcl and you are asked to create 15 mls of a 1.7m working solution. what do you do? select one: a. add 8.5 ml. of stock to 6.5 ml water. b. add 1.7 ml of stock to 13.3 ml water. c. add 1.7 ml of stock to 15 ml of water. d. add 8.5 ml of stock to 15 ml water.

Explanation:

Step1: Use dilution formula

$C_1V_1 = C_2V_2$, where $C_1$ is initial concentration, $V_1$ is volume of initial solution, $C_2$ is final concentration and $V_2$ is final volume.

Step2: Substitute values

Given $C_1 = 3M$, $C_2=1.7M$, $V_2 = 15ml$. We need to find $V_1$. Rearranging formula gives $V_1=\frac{C_2V_2}{C_1}$. So $V_1=\frac{1.7M\times15ml}{3M}=8.5ml$.

Step3: Calculate volume of water

Volume of water = $V_2 - V_1=15ml - 8.5ml = 6.5ml$. So we add 8.5 ml of stock to 6.5 ml water.

Answer:

A. Add 8.5 ml of stock to 6.5 ml water.