ANSWERS - Percent Concentration Practice Worksheet
1. What is the % M/M if 8.0 g copper is added to enough zinc to produce 100 g of
an alloy? 8% M/M
2. Brass is a copper-zinc alloy. If the concentration of zinc is relatively low, the
brass has a golden color and is often used for inexpensive jewellery. If a 35.0 g
pendant contains 1.7 g of zinc, what is the percentage mass by mass of zinc in
brass? 4.9% M/M
3. What is the % M/M of copper in an alloy when 10 kg of Cu is mixed with 250
kg of Zn? 3.8% M/M
4. You have 200g of a solution that contains 30g of hydrochloric acid (HCl), what
percentage of your solution is made up of hydrochloric acid (M/M)? 15% M/M
5. If I make a solution by adding water to 75 mL of ethanol until the total volume
of the solution is 375 mL, what’s the percent by volume of ethanol in the
solution? 20% V/V
6. How would you make 500mL of 30% vinegar in water solution?
30mL vinegar x 500mL sol’n = 150mL
100mL sol’n
So, you would place 150mL of vinegar in a flask and bring to level (500mL)
with water.
