Solutions, Dilutions & Molarity

What is a "solution" in chemistry?

• A) A mixture of two metals

• B) A type of chemical reaction

• C) A homogeneous mixture of two or more substances

• D) A special kind of solvent

Answer explanation

A solution in chemistry is a homogeneous mixture of two or more substances, making choice C the correct answer.

Which term describes the substance that is dissolved in a solution?

• A) Solvent

• B) Solute

• C) Suspension

• D) Precipitate

Answer explanation

The term that describes the substance dissolved in a solution is the solute, making option B the correct choice.

What is commonly referred to as the "universal solvent"?

• A) Alcohol

• B) Water

• C) Acetone

• D) Oil

Answer explanation

Water is commonly referred to as the 'universal solvent' due to its ability to dissolve a wide range of substances.

Which statement best explains the principle "like dissolves like"?

• A) Solvents can only dissolve solutes of the same color

• B) Polar solvents dissolve polar solutes, and non-polar solvents dissolve non-polar solutes

• C) Only liquids can dissolve other liquids

• D) Solutes and solvents of the same density mix well

Answer explanation

Polar solvents dissolve polar solutes, and non-polar solvents dissolve non-polar solutes

Can both polar covalent bonds and ionic bonds be dissolved in water? If so, why?

• A) Yes, because water is a polar solvent

• B) No, because water can only dissolve ionic bonds

• C) Yes, but only at high temperatures

• D) No, because water is non-polar

Answer explanation

Yes, because water is a polar solvent

What is the definition of Molarity?

• The mass of solute per liter of solution

• The number of moles of solute per liter of solution

• The volume of solute per liter of solution

• The number of molecules per liter of solution

Answer explanation

The number of moles of solute per liter of solution

What is the formula for Molarity?

• Mass / Volume

• Moles / Volume

• Volume / Moles

• Moles * Volume

Answer explanation

The formula for Molarity is Moles / Volume. Molarity is defined as the number of moles of solute per liter of solution.

How many grams of H₂SO₄ do you need to make 1.00L of a 3.50M solution?

• 350 grams

• 245 grams

• 98 grams

• 490 grams

Answer explanation

To calculate the grams of H₂SO₄ needed, use the formula: grams = moles x molar mass. Moles = Molarity x Volume (in L). Molar mass of H₂SO₄ = 98.08 g/mol. Therefore, grams = 3.50 mol/L x 1.00 L x 98.08 g/mol = 490 grams.

How many moles of NaOH are in 65.0ml of a 2.20M solution of NaOH?

• 0.143 moles

• 0.065 moles

• 0.220 moles

• 0.500 moles

Answer explanation

To calculate the moles of NaOH, use the formula Moles = Molarity x Volume (in L). Moles = 2.20 x 0.065 = 0.143 moles. Therefore, the correct answer is 0.143 moles.

What is the molarity of a solution made by dissolving 26.42g of (NH₄)₂SO₄ in enough water to make 50.00ml of solution?

• 2.00 M

• 1.00 M

• 3.00 M

• 0.50 M

Answer explanation

To find the molarity, first calculate the moles of (NH₄)₂SO₄. Then, divide moles by liters (50.00ml = 0.050L) to get 1.00 M.