Identify the group or period that matches each description.
1 answer:
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Answer:
- 9 grams
Explanation:
Percentage is a concentration unit that describes the amount of a solute in 100 parts of total substance (solution).
The weight percent of a solution is given by the formula:
- % (w/w) = (mass of solute / mass of solution) × 100
Here, the red food coloring is the solute, water is the solvent, and the solution is the mixture.
You know the mass of water (50 g) and the percentage (15%), thus you can calculate the mass of red food coloring (x) in this way:
<u>1. Mass of solution</u>
- Mass of solution = mass of red food coloring + mass of water
- mass of solution = x + 50
<u>2. Percent</u>
% = x / (x + 50) × 100 = 15
<u>3. Solve for x:</u>
- x / (x + 50) = 0.15
- x = 0.15(x + 50)
- x = 0.15x + 7.5
- 0.85x = 7.5
- x = 8.82 g
Round to two one significant figure, because the number 50 grams has one significant figure.
- x = 9 grams.