Question

fill in the missing words
a) one of the ways to make 250 ml of a 0.077 m solution of a sodium hydroxide, is to mix \boxed{} ml of a 1.2 m solution of sodium hydroxide and \boxed{} ml of water.
b) one of the ways to make 1.0 l of a 0.55 m solution of magnesium sulfate, is to mix \boxed{} ml of a 2.5 m solution of magnesium sulfate and add enough water to make 1.0 l of the solution.

Explanation:

Part (a)

Step1: Use dilution formula \( M_1V_1 = M_2V_2 \)

We know \( M_1 = 1.2\ M \), \( M_2 = 0.077\ M \), \( V_2 = 250\ mL \). Solve for \( V_1 \):
\( V_1=\frac{M_2V_2}{M_1}=\frac{0.077\ M\times250\ mL}{1.2\ M} \)

Step2: Calculate \( V_1 \)

\( V_1=\frac{0.077\times250}{1.2}\approx16.04\ mL \) (volume of 1.2 M NaOH)

Step3: Calculate water volume

Total volume is 250 mL, so water volume \( = 250 - 16.04 = 233.96\ mL \)

Step1: Use dilution formula \( M_1V_1 = M_2V_2 \)

\( M_1 = 2.5\ M \), \( M_2 = 0.55\ M \), \( V_2 = 1.0\ L = 1000\ mL \). Solve for \( V_1 \):
\( V_1=\frac{M_2V_2}{M_1}=\frac{0.55\ M\times1000\ mL}{2.5\ M} \)

Step2: Calculate \( V_1 \)

\( V_1=\frac{0.55\times1000}{2.5}=220\ mL \)

Answer:

16.04, 233.96

Part (b)