Question

A solution is made by combining 4.00 g of sugar and 100 mL of water (density = 1.00 g/mL). What is the concentration in % w/w?

a. 26.0

b. 4.00

c. 0.0400

d. 3.85

Answer 1

The concentration of the solution in percent by weight/weight (% w/w) is found by dividing the mass of the solute (sugar) by the total mass of the solution (solute plus solvent) and then multiplying by 100%. For 4.00 g of sugar dissolved in 100 mL of water, the concentration is approximately 3.85% w/w.

Step-by-step explanation:

To calculate the concentration of the solution in % w/w (percent by weight/weight), we use the formula:

Percent by mass = (mass of solute / (mass of solute + mass of solvent)) × 100%

Given that the mass of sugar (solute) is 4.00 g and the volume of water (solvent) is 100 mL with a density of 1.00 g/mL, the mass of water is:

Mass of water = (Density of water) × (Volume of water) = 1.00 g/mL × 100 mL = 100.00 g

Now, let's calculate the % w/w:

Percent by mass = (4.00 g / (4.00 g + 100.00 g)) × 100% = (4.00 g / 104.00 g) × 100% ≈ 3.85%

Therefore, the correct answer is d. 3.85.