Solutions

What is it about the water molecule that makes it a great solvent?

• water demonstrates polarity; a partial charge on each side of the molecule
• due to its molecular formula
• it has a liner molecular shape
• due to it's non-polar molecular structure

Tags

NGSS.HS-PS1-3

What is the correct formula to solve for the Molarity of a solution that has .4 moles of HCl in 9.5 L of solution?

• M = 9.5 L / .4 mol
• M₁V₁=M₂V₂
• M = .4 mol / 9.5 L
• none of the other choices

A sample of 0.0255 mol potassium hydroxide, KOH, was dissolved in water to yield 10.0 mL of
solution.  Which amount would you need to change to solve for molarity?

• change .0255 moles to grams
• change 10 mL to L
• change both values to grams and L
• leave it as it is

A questions asks, "what volume of 0.125 M KMnO4 is required to yield 0.180 mol of potassium permanganate,
KMnO4?"  What is the correct formula set up to solve for this problem?

• .125 M = .180 mol / L
• M₁ V₁ = M₂ V₂
• .125 M = L / .180 mol
• none of the choices listed

Which formula should you use to convert 2.00 L of 0.300 M sulfuric acid, how many mL of a 1.00 M stock solution should be
used?

• molarity formula
• dilution formula
• both will work
• neither will work

Which of the following would result in being able to dissolve a greater amount of gas in a
solution?

• Heat the gas and solution
• Decrease the pressure of the solution
• Make the gas an electrolyte
• Cool the gas and solution

90 grams of sodium nitrate (NaNO3) are put into 100 grams of water and stirred. The final
mixture has a temperature of 20°C. About how many grams of the sodium nitrate dissolved?

• 23
• 73
• 80
• 88

Tags

NGSS.HS-ESS2-5

Students are asked to make statements about the solubility graph above. Which student does
the best job of communicating the general features of the graph?

• Most salts require 100 grams of water in order to dissolve completely.
• Table salt has the average solubility of all salts.
• The solubility of most salts increases with increasing temperature.
• Most curves show a decreasing slope as the temperature rises.

Which of the following would decrease the rate of solution when dissolving a solid in water?

• Raise the temperature of the solution
• Crush the solid before mixing
• Stir the solution after mixing
• Use a single cube of solid

Which of the following is the best way to determine if an aqueous solution  is supersaturated?

• add more solvent
• measure the temperature
• filter out excess solute
• add a seed crystal