Solutions Molarity/solubility

Magnesium hydroxide, Mg(OH)₂, is a common antacid. What is the molar concentration if 29.0 g of Mg(OH)₂ is dissolved in 1.00 L of water? MM Mg(OH)2=58.3g/mol)

• 0.29 M

• 0.50 M

• 1.00 M

• 2.00 M

What is the concentration in molarity when 11.0 g of CaCl₂ is added to water to make a 100 mL solution?

• 0.10 M

• 1.00 M

• 11.0 M

• 110 M

Determine the molarity of a solution that is prepared by diluting 200 mL of 0.450 M K₂Cr₂O₇ with 600 mL of water.

• 0.075 M

• 0.112 M

• 0.150 M

• 0.225 M

What is the concentration of a solution if 2.0 moles of sodium chloride is dissolved in 0.50 liter of water?

• 0.5 M

• 1.0 M

• 2.0 M

• 4.0 M

What is the concentration of a solution that was made by adding 10.00 g of KF in 2.0 L of water?

(molar mass K = 39.09; F = 19.99)

• 5.0 mol/L

• 0.25 mol/L

• 0.13 mol/L

• 0.085 mol/L

Tags

NGSS.HS-PS1-7

How is a supersaturated aqueous solution of salt in water prepared?

• Add salt to water and heat until the salt dissolves completely.

• Prepare a warm saturated solution and then cool the solution.

• Prepare a cool saturated solution and then warm the solution.

• Add a large amount of salt to water and then filter off the excess salt.

The temperature of a stream whose water is saturated with dissolved oxygen increases from 15°C to 22°C on a sunny day. How does this affect the concentration of oxygen in the water?

• The oxygen concentration decreases because the solubility of oxygen decreases.

• The concentration of oxygen does not change but the solution is no longer saturated.

• The solubility of oxygen increases but the water remains saturated with oxygen.

• The oxygen concentration is not affected because temperature is not related to saturation.

Tags

NGSS.HS-PS1-5

In an experiment, 2.0 g of solid sodium bicarbonate (NaHCO₃) was tested for solubility. At 20°C and stirring, it took 60 minutes to dissolve. At 20°C and no stirring, it took 90 minutes to dissolve. Why is stirring a factor in the dissolving of the NaHCO₃?

• Stirring increases the contact of the solute to the solvent.

• Stirring increases the temperature of the solution.

• Stirring increases pressure.

• Stirring increases surface area.

Two samples of the substance shown will be dissolved in a solution. One sample is a single large piece, and the other has been broken into many smaller pieces.

Which sentence best describes how the dissolution will proceed?

• The substance will dissolve more quickly if broken into small pieces because of increased surface area.

• The substance will dissolve more slowly if broken into small pieces because more particles can react.

• The substance will dissolve more quickly if broken into small pieces because of decreased mass.

• The substance will dissolve more slowly if broken into small pieces because of increased mass.

Why will a cold glass of soda remain carbonated longer than a warm glass of soda?

• Ice in the glass creates more surface area for the attachment of the carbonated gas.

• Condensation against the cold glass surface reduces the dissolving rate of the gas.

• Higher temperature liquids release carbonation into the atmosphere more slowly.

• Carbon dioxide is more soluble in liquids at lower temperatures.