Let's solve these questions step by step.

Question 14: What is the percentage of the solution?

We are given:

• 20 grams of solute
• 0.5 L of water (which is 500 mL since 1 L = 1000 mL)

The formula for calculating the percentage of a solution is:

$\text{Percentage} = \left( \frac{\text{mass of solute}}{\text{total mass of solution}} \right) \times 100$

Total mass of the solution = mass of solute + mass of solvent (water). Since the density of water is approximately 1 g/mL, the mass of water is:

$500 \, \text{mL} = 500 \, \text{grams}$

Now, calculate the total mass of the solution:

$\text{Total mass of solution} = 20 \, \text{g} + 500 \, \text{g} = 520 \, \text{g}$

Now calculate the percentage:

$\text{Percentage} = \left( \frac{20}{520} \right) \times 100 \approx 3.85\%$

So, none of the provided answer choices exactly match, but based on approximation, the closest one would be 4%.

Question 15: How many milliliters of a 3% solution can be made with 6 grams of solute?

We are given:

• 6 grams of solute
• 3% solution

We can use the formula for percentage solutions:

$\text{Percentage} = \left( \frac{\text{mass of solute}}{\text{volume of solution}} \right) \times 100$

Rearranging to find the volume of solution:

$\text{Volume of solution} = \frac{\text{mass of solute}}{\text{Percentage} \times 100} = \frac{6 \, \text{g}}{3}$

$\text{Volume of solution} = 200 \, \text{mL}$

So, the correct answer is 200 mL.

Final Answers:

• Question 14: B) 4%
• Question 15: B) 200 mL

Would you like further details or clarifications on any step? Here are 5 related questions for you to explore:

1. How would the result change if the density of water was different from 1 g/mL?
2. What is the difference between mass percentage and volume percentage solutions?
3. How do you calculate molarity and molality for a given solution?
4. How can you determine the concentration of a solution from a titration experiment?
5. What is the role of solute and solvent in determining the properties of a solution?

Tip: When calculating percentage solutions, always ensure you're consistent with your units (grams, milliliters, etc.), especially when working with water or other solvents.