Exploring Solution Properties _I

What is the definition of a saturated solution?

• A solution that can dissolve more solute at a given temperature.

• A solution that contains the maximum amount of solute that can be dissolved at a given temperature.

• A solution that contains less solute than it can dissolve at a given temperature.

• A solution that contains no solute.

Answer explanation

A saturated solution is defined as one that contains the maximum amount of solute that can be dissolved at a given temperature, meaning it cannot dissolve any more solute without changing conditions.

Which of the following factors does NOT affect the solubility of a solid in a liquid?

• Temperature

• Pressure

• Nature of the solute and solvent

• Stirring

Answer explanation

Pressure does not significantly affect the solubility of solids in liquids, unlike temperature, the nature of the solute and solvent, and stirring, which all play crucial roles in solubility.

Calculate the molarity of a solution prepared by dissolving 5 moles of solute in 2 liters of solution.

• 2.5 M

• 5 M

• 10 M

• 2 M

Answer explanation

Molarity (M) is calculated as moles of solute divided by liters of solution. Here, 5 moles / 2 liters = 2.5 M. Therefore, the correct answer is 2.5 M.

If the solubility of a gas in water is 0.5 g/L at 1 atm, what will be its solubility at 2 atm, assuming temperature remains constant?

• 0.25 g/L

• 0.5 g/L

• 1.0 g/L

• 2.0 g/L

Answer explanation

According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure. If the solubility is 0.5 g/L at 1 atm, at 2 atm it will be 0.5 g/L x 2 = 1.0 g/L.

Explain why increasing the temperature generally increases the solubility of solids in liquids.

• It increases the kinetic energy of the molecules, allowing more solute to dissolve.

• It decreases the kinetic energy of the molecules, allowing more solute to dissolve.

• It increases the pressure, allowing more solute to dissolve.

• It decreases the pressure, allowing more solute to dissolve.

Answer explanation

Increasing the temperature raises the kinetic energy of the molecules in the solvent, which enhances the movement and interaction between solute and solvent, allowing more solute to dissolve.

Tags

NGSS.HS-PS3-2

NGSS.HS-PS3-4

A solution is prepared by dissolving 10 g of NaCl in 90 g of water. What is the mass percent of NaCl in the solution?

• 10%

• 11.1%

• 9.1%

• 12.5%

Answer explanation

To find the mass percent of NaCl, use the formula: (mass of solute / total mass of solution) x 100. Here, total mass = 10 g (NaCl) + 90 g (water) = 100 g. Thus, (10 g / 100 g) x 100 = 10%. However, the correct calculation is (10 g / (10 g + 90 g)) x 100 = 11.1%.

Which of the following statements best describes an unsaturated solution?

• It contains more solute than can be dissolved at a given temperature.

• It contains the maximum amount of solute that can be dissolved at a given temperature.

• It contains less solute than can be dissolved at a given temperature.

• It contains no solute.

Answer explanation

An unsaturated solution contains less solute than can be dissolved at a given temperature, meaning it can still dissolve more solute. This distinguishes it from saturated solutions, which hold the maximum amount.

Determine the mole fraction of solute in a solution containing 2 moles of solute and 8 moles of solvent.

• 0.2

• 0.25

• 0.8

• 0.75

Answer explanation

The mole fraction of solute is calculated as the moles of solute divided by the total moles in the solution. Here, it is 2 moles of solute / (2 moles of solute + 8 moles of solvent) = 2/10 = 0.2.

What is the effect of pressure on the solubility of gases in liquids?

• Solubility decreases with increasing pressure.

• Solubility increases with increasing pressure.

• Solubility is unaffected by pressure.

• Solubility first increases and then decreases with increasing pressure.

Answer explanation

According to Henry's Law, the solubility of gases in liquids increases with increasing pressure. This is because higher pressure forces more gas molecules into the liquid, enhancing solubility.

A solution has a molality of 3 mol/kg. If the solvent is water, what is the approximate molarity of the solution, assuming the density of water is 1 kg/L?

• 3 M

• 6 M

• 1.5 M

• 0.5 M

Answer explanation

Molality (3 mol/kg) means 3 moles of solute per kg of solvent. With water's density at 1 kg/L, 1 kg of water is 1 L. Thus, the molarity is 3 moles in 1 L, resulting in approximately 3 M. Therefore, the correct answer is 3 M.