HChem Unit 8 Test Review

About how many grams of water would be needed to dissolve 20 g of potassium chlorate at 30 degrees Celsius.

• 5 g

• 10 g

• 20 g

• 100 g

• 200 g

Answer explanation

At 30 degrees Celsius, 10 g can be dissolved in 100 g of water.

Tags

NGSS.HS-ESS2-5

• unsaturated

• saturated

• supersaturated

• none of these

Answer explanation

Density of water is 1 g/mL. 55 mL = 55 g. Solve the proportion for amount of solute compared to 100 g of water.

You have a saturated solution of KCl at 40 degrees Celsius. What is the percent by mass of KCl in the solution?

• 40%

• 18%

• 62%

• 29%

Tags

NGSS.HS-PS1-5

Based on the table, which of the following statements is correct?

• Solids generally become less soluble in water as temperature increases

• Temperature generally has no effect on the solubility of solids in water

• Solids generally become more soluble in water as temperature increases

Tags

NGSS.MS-PS1-4

• 25.0

• 111

• 55.6

• 27.8

• 0.113

In general, a solid becomes more soluble in water at

• high temperature and low pressure

• low temperature and high pressure

• high temperature and high pressure

• low temperature only, solubility of solids are not affected by pressure

• high temperature only, solubility of solids are not affected by pressure

If 25 mL of 0.15 M solution of HCl is added to 45 mL of 0.25 M solution of HCl, what would be the molarity of the final mixture?

• 0.15 M

• 0.20 M

• 0.21 M

• 0.23 M

• 0.25 M

What mass of solid sodium hydroxide is required to prepare 2.00 L of a 3.00 M solution?

• 40 g

• 80 g

• 240 g

• 480 g

• 667 g

What is the molarity of HCl when a solution is made by adding 20 mL of 6.0 M HCl to 28 mL of water? (Assume volumes are additive)

• 5.0 M

• 4.6 M

• 4.3 M

• 2.8 M

• 2.5 M

You have 50.0 grams of water at 30 degrees Celsius. You put 40.0 grams of KNO₃ into the water and stir. Which of the following occurs?

• Not all of the KNO₃ will dissolve and forms a saturated solution.

• All of the KNO₃ will dissolve and forms a supersaturated solution.

• All of the KNO₃ will dissolve and forms a saturated solution.

• All of the KNO₃ will dissolve and forms an unsaturated solution.

Answer explanation

A supersaturated solution only happens when all solute dissolves at a higher temp and is cooled down to a lower temp.

Tags

NGSS.HS-PS1-5