Percent Concentration

Juan wanted to find out whether the concentration of salt in water affected how long it takes water to cool. He put 4 identical plastic glasses, each of which contained 225 mL of a different concentration of salt solution, into a freezer. The different salt concentrations were 0 percent, 10 percent, 20 percent, and 30 percent. He recorded the amount of time it took for each solution to cool to a temperature of 3 degrees Celsius.

What are the constants? (can be more than one)

• Glasses

• Volume of salt solution

• Freezer

• Concentration of salt solution

• Amount of time in freezer for solution to cool to 3 degrees Celsius

What is the concentration, in percent by volume, of 15.3 mL of solute in 2.65 L of solution?

• 0.58%

• 0.0058%

• 5.8%

What is the perecent by mass of a solution that contains 12.0 g of solute per 200.0 g solution?

• 5.6 %

• 6 %

• 2.4 %

What mass of water should be added to 22.0 g of KCl to make 5.50% by mass solution?

• 400 g

• 25 g

• 0.25 g

Calculate the mass % concentration of 38.5 aqueous solution that contains 1.96 g of Nabr.

• 5.2%

• 5.09%

• 509%

You can make a solution more concentrated by adding more __________.

• solute

• solvent

• water

To find ________________ we divide mass ofg solute with the mass of solution times 100.

• percent by mass

• percent by volume

• parts per hundred

What is the percent concentration by mass of a solution containing 25 g of solute in 175 g of solution?

• 12.5%

• 14.3%

• 16.7%

• 10.0%

A solution is made by dissolving 10 mL of ethanol in 90 mL of water. What is the percent concentration by volume of ethanol in the solution?

• 10%

• 11.1%

• 9.1%

• 12%

If you have a 20% saline solution, how many grams of salt are present in 100 g of this solution?

• 20 g

• 15 g

• 25 g

• 10 g