Question 1

What is the molarity of a solution prepared by dissolving 48.0 g of NaOH in enough water to make 1.50 L of solution?
A)0.0313 M
B)0.556 M
C)0.800 M
D)1.28 M
E)32.0 M

Accepted Answer

The first step in solving the problem is to calculate the number of moles of NaOH that were dissolved in the solution:

moles of NaOH = mass / molar mass
moles of NaOH = 48.0 g / 40.00 g/mol
moles of NaOH = 1.20 mol

Next, we need to calculate the molarity of the solution:

molarity = moles of solute / liters of solution
molarity = 1.20 mol / 1.50 L
molarity = 0.800 M

Therefore, the answer is C.

Question 2

What is the molarity of a solution prepared by dissolving 3.50 mol NaCl in enough water to make 1.50 L of solution?
A)0.429 M
B)2.33 M
C)5.25 M
D)87.8 M
E)137 M

Accepted Answer

Molarity is calculated by dividing the number of moles of solute by the volume of the solution in liters. For this problem, $ \text{Molarity} = \frac{3.50 \, \text{mol}}{1.50 \, \text{L}} = 2.33 \, \text{M} $.

Question 3

Calculate the concentration of nitrogen gas in water with a nitrogen gas at a partial pressure of 0.826 atm above it.Henry's law constant for nitrogen in water is 6.8 × 10^-4 mol/L-atm. A)5.6 × 10^-4M B)8.2 × 10^-3M C)1.2 × 10³ M D)0.43 M

Accepted Answer

Using Henry's law, the concentration of a gas in a liquid is given by $C = kP$, where $C$ is the concentration, $k$ is Henry's law constant, and $P$ is the partial pressure of the gas. Substituting the given values, $C = 6.8 \times 10^{-4} \times 0.826 = 5.6 \times 10^{-4} \, \text{M}$.

Question 4

Pressure has a large effect only on the solubility of ________ in liquids.
A)liquid
B)solid
C)gas
D)all of the above
E)none of the above

Accepted Answer

Pressure has a large effect on the solubility of gases in liquids due to gas molecules being more easily compressed under pressure, allowing them to dissolve more readily in a liquid. Pressure has minimal effects on the solubility of solids or liquids in other liquids.

Question 5

What is the % (w/v)concentration of a solution containing 8.0 grams of alcohol in 50.0 mL of solution?
A)2.0%
B)4.0%
C)8.0%
D)16%
E)50%

Accepted Answer

The answer of What is the % (w/v)concentration of a...

Question 6

The solubility of gases in liquids
A)increases as temperature increases and increases as pressure increases.
B)decreases as temperature increases and increases as pressure increases.
C)decreases as temperature increases and decreases as pressure increases.
D)increases as temperature increases and decreases as pressure increases.
E)is independent of temperature and increases as pressure increases.

Accepted Answer

The solubility of gases in liquids decreases with an increase in temperature but increases with an increase in pressure, according to Henry's Law.

Question 7

In general,the solubility of ________ in water decreases as temperature increases.
A)gases
B)solids
C)liquids
D)none of these
E)all of these

Accepted Answer

The solubility of gases in water follows Henry's Law, which states that the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas above the liquid. As temperature increases, the kinetic energy of gas molecules also increases, leading to a decrease in the partial pressure of gas and therefore a decrease in solubility in water.

Question 8

How much NaOH is present in a 250.mL sample of a 5.00% (w/v)solution?
A)5.00 g
B)10.0 g
C)12.5 g
D)25.0 g
E)250 g

Accepted Answer

To find the amount of NaOH present in the 5.00% (w/v) solution, we need to first convert the percentage to grams per milliliter (g/mL).

5.00% (w/v) means that there are 5.00 grams of NaOH present in 100 mL of solution.

So, we can calculate the amount of NaOH in the 250 mL sample as follows:

5.00 g NaOH / 100 mL solution = x g NaOH / 250 mL solution

x = (5.00 g NaOH / 100 mL solution) * 250 mL solution 
x = 12.5 g NaOH

Therefore, the answer is C) 12.5 g.

Question 9

What is the molarity of a solution prepared by dissolving 0.750 mol CaCl₂ in enough water to make 0.500 L of solution? A)0.375 M B)0.667 M C)1.50 M D)83.2 M E)166.5 M

Accepted Answer

The answer of What is the molarity of a solution...

Question 10

What is the molarity of a solution prepared by dissolving 1.25 mol of AgNO₃ in enough water to make 625 mL of solution? A)2.00 M B)0.00200 M C)0.500 M D)0.0118 M E)0.340 M

Accepted Answer

Molarity = moles of solute / liters of solutionMolarity = 1.25 mol / 0.625 LMolarity = 2.00 M

Question 11

How many moles of HCl are present in 75.0 mL of a 0.200 M solution?
A)15.0 mol
B)2.67 mol
C)0.375 mol
D)0.275 mol
E)0.0150 mol

Accepted Answer

To find the number of moles of HCl in the solution, use the formula: moles = molarity (M) × volume (L). Convert 75.0 mL to liters (0.0750 L) and multiply by the molarity (0.200 M): 0.200 M × 0.0750 L = 0.0150 moles.

Question 12

Which solution is the most concentrated? Each choice refers to the same solute and solvent.
A)2.4 g solute in 2 mL solution
B)2.4 g solute in 5 mL solution
C)20 g solute in 50 mL solution
D)30 g solute in 150 mL solution
E)50 g solute in 175 mL solution

Accepted Answer

Concentration is calculated as mass of solute divided by volume of solution. A) has the highest concentration with 2.4 g/2 mL = 1.2 g/mL.

Question 13

The solubility of nitrogen in water exposed to the atmosphere,where the partial pressure of nitrogen is 593 mm,is 5.3 × 10^-4 M.At the same temperature,what would be the solubility of pure nitrogen,at a pressure of 760 mm? A)4.1 × 10^-4 M B)6.8 × 10^-4 M C)1500 M D)2400 M E)none of the above

Accepted Answer

The solubility of a gas is directly proportional to the partial pressure of the gas above the liquid. Therefore, we can use the following equation:

Solubility1/Solubility2 = Partial pressure1/Partial pressure2

where Solubility1 is the solubility of nitrogen in water at a partial pressure of 593 mm, and Solubility2 is the solubility of pure nitrogen at a pressure of 760 mm.

Substituting the known values:

5.3 × 10^-4 / Solubility2 = 593 / 760

Solving for Solubility2:

Solubility2 = 6.8 × 10^-4 M

Therefore, the answer is B.

Question 14

Which solution is the least concentrated? Each choice refers to the same solute and solvent.
A)2.4 g solute in 2 mL solution
B)2.4 g solute in 5 mL solution
C)20 g solute in 50 mL solution
D)30 g solute in 150 mL solution
E)50 g solute in 175 mL solution

Accepted Answer

The concentration of a solution is determined by the ratio of solute to solvent. In choice D, the ratio of solute (30 g) to solvent (150 mL) is the lowest, making it the least concentrated solution.

Question 15

What is the molarity of a solution prepared by dissolving 10.0 g of acetone,C₃H₆O,in enough water to make 125 mL of solution? A)4.65 M B)1.38 M C)0.0465 M D)0.0214 M E)0.0125 M

Accepted Answer

To find the molarity of the solution, we need to first calculate the number of moles of acetone present in the solution.

Number of moles = Mass of solute / Molar mass of solute

Molar mass of acetone = 2 x Atomic mass of carbon + 6 x Atomic mass of hydrogen + Atomic mass of oxygen
= (2 x 12.01 g/mol) + (6 x 1.01 g/mol) + 16.00 g/mol
= 58.08 g/mol

Number of moles of acetone = 10.0 g / 58.08 g/mol
= 0.172 moles

Volume of solution = 125 mL = 0.125 L

Molarity = Number of moles / Volume of solution
= 0.172 moles / 0.125 L
= 1.376 M

Thus, the molarity of the solution is 1.38 M (rounded to two decimal places).

The correct answer is choice B, 1.38 M.

Question 16

How many grams of NaOH are needed to make 750 mL of a 2.5% (w/v)solution?
A)3.9 g
B)7.5 g
C)19 g
D)20 g
E)50 g

Accepted Answer

We can start by using the formula:

mass (g) = volume (mL) x concentration (w/v)

Converting the given volume to grams:

750 mL x 1 g/mL = 750 g

Substituting the values into the formula:

mass (g) = 750 g x 2.5% = 18.75 g

Rounding off to the nearest gram, we get:

mass (g) = 19 g

Therefore, the correct answer is C) 19 g.

Question 17

Which information is necessary to determine the molarity of a solution if the chemical formula of the solute is known?
A)only the mass of solute dissolved
B)only the volume of solvent used
C)the molar mass of both the solute and the solvent used
D)the mass of solute dissolved and the volume of solvent added
E)the mass of solute dissolved and the final volume of the solution

Accepted Answer

Molarity is defined as the number of moles of solute per liter of solution. To find the molarity, you need the mass of the solute dissolved to calculate the moles of solute (using the molar mass from the chemical formula) and the final volume of the solution to determine the volume in liters.

Question 18

All of the statements about molarity are correct except
A)the abbreviation is M.
B)the interpretation of the symbol is "moles of solute per mole of solvent."
C)moles = molarity × volume.
D)volume = moles/molarity.
E)the molarity of a diluted solution is less than the molarity of the original solution.

Accepted Answer

The interpretation of the symbol for molarity is "moles of solute per liter of solution," not "moles of solute per mole of solvent."

Question 19

What is the % (w/v)concentration of a solution containing 25.0 g of solute in 400.mL of solution?
A)2.50%
B)5.00%
C)6.25%
D)12.5%
E)25.0%

Accepted Answer

% (w/v) concentration = (mass of solute ÷ volume of solution) x 100%
% (w/v) concentration = (25.0 g ÷ 400. mL) x 100%
% (w/v) concentration = 0.0625 x 100%
% (w/v) concentration = 6.25%

Question 20

How much NaCl is needed to make 50.0 mL of a 16% (w/v)solution?
A)2.0 g
B)4.0 g
C)8.0 g
D)12 g
E)16 g

Accepted Answer

A 16% (w/v) solution means that 16 g of NaCl is present in 100 mL of solution.

To make 50.0 mL of solution, we can use the proportion:

16 g/100 mL = x g/50.0 mL

Solving for x:

x = 8.0 g

Therefore, 8.0 g of NaCl is needed to make 50.0 mL of a 16% (w/v) solution.

Quiz 9: Solutions

What is the molarity of a solution prepared by dissolving 48.0 g of NaOH in enough water to make 1.50 L of solution?

What is the molarity of a solution prepared by dissolving 3.50 mol NaCl in enough water to make 1.50 L of solution?

Calculate the concentration of nitrogen gas in water with a nitrogen gas at a partial pressure of 0.826 atm above it.Henry's law constant for nitrogen in water is 6.8 × 10^-4 mol/L-atm.

Pressure has a large effect only on the solubility of ________ in liquids.

What is the % (w/v) concentration of a solution containing 8.0 grams of alcohol in 50.0 mL of solution?

The solubility of gases in liquids

In general,the solubility of ________ in water decreases as temperature increases.

How much NaOH is present in a 250.mL sample of a 5.00% (w/v) solution?

What is the molarity of a solution prepared by dissolving 0.750 mol CaCl₂ in enough water to make 0.500 L of solution?

What is the molarity of a solution prepared by dissolving 1.25 mol of AgNO₃ in enough water to make 625 mL of solution?

How many moles of HCl are present in 75.0 mL of a 0.200 M solution?

Which solution is the most concentrated? Each choice refers to the same solute and solvent.

The solubility of nitrogen in water exposed to the atmosphere,where the partial pressure of nitrogen is 593 mm,is 5.3 × 10^-4 M.At the same temperature,what would be the solubility of pure nitrogen,at a pressure of 760 mm?

Which solution is the least concentrated? Each choice refers to the same solute and solvent.

What is the molarity of a solution prepared by dissolving 10.0 g of acetone,C₃H₆O,in enough water to make 125 mL of solution?

How many grams of NaOH are needed to make 750 mL of a 2.5% (w/v) solution?

Which information is necessary to determine the molarity of a solution if the chemical formula of the solute is known?

All of the statements about molarity are correct except

What is the % (w/v) concentration of a solution containing 25.0 g of solute in 400.mL of solution?

How much NaCl is needed to make 50.0 mL of a 16% (w/v) solution?