Question 1

The World Health Organization recommends that the maximum allowable concentration of chromium(VI) in drinking water be limited to 0.05 mg/L. If the molar absorptivity of chromium(VI) at 345 nm is 1.5*10³/(M cm), what is the absorbance of a solution that contains 0.050 mg/L in a 10-cm-long cell?

Accepted Answer

First, we need to convert the concentration from mg/L to mol/L. The molecular weight of chromium(VI) is 52 g/mol, so:

0.050 mg/L = 0.050 mg/L x (1 g/1000 mg) x (1 mol/52 g) x (1000 L/1 m3) = 9.6 x 10-10 mol/L

Next, we can calculate the absorbance using the Beer-Lambert law:

A = εcl
where A is the absorbance, ε is the molar absorptivity, c is the concentration in mol/L, and l is the path length in cm.

Plugging in the values we have:

A = (1.5 x 1010 M-1 cm-1) x (9.6 x 10-10 mol/L) x (10 cm) = 0.014

Therefore, the absorbance of the solution is 0.014, which is choice C.

Question 2

In a demonstration of strong electrolytes, weak electrolytes, and nonelectrolytes, Professor Popsnorkle used a lightbulb apparatus that showed how much a solution conducted electricity by the brightness of the lightbulb. When pure water was tested, the bulb did not light. Then Professor Popsnorkle tested the following aqueous solutions. Which one caused the bulb to burn dimly but not brightly?

Accepted Answer

Acetic acid (CH3COOH) is a weak electrolyte, meaning it partially dissociates into ions in solution. This partial dissociation allows for some conductivity and causes the lightbulb to burn dimly. Strong electrolytes, like table salt (NaCl), fully dissociate into ions and cause the lightbulb to burn brightly. Nonelectrolytes, like table sugar (C12H22O11) and ethanol (C2H5OH), do not dissociate into ions and do not conduct electricity, so the lightbulb does not light up at all. Methanol (CH3OH) is a type of alcohol, similar to ethanol, and is also a nonelectrolyte.

Question 3

Diluting 1.0 mL of a 1.0 M solution to 1,000 mL results in a solution that is 0.001 M. Repeating this 1,000-fold dilution process five more times results in a concentration of __________

Accepted Answer

Each 1,000-fold dilution reduces the concentration by a factor of 1,000 (10^3). After six such dilutions, the concentration is reduced by a factor of (10^3)^6 = 10^18, resulting in a final concentration of 1.0 * 10^-18 M.

Question 4

Which contains more solute particles: a 0.10 M aqueous solution of methanol (CH₃OH) or a 0.10 M aqueous solution of salt (NaCl)?

Accepted Answer

When NaCl dissolves in water, it dissociates into two ions: Na+ and Cl-. Therefore, a 0.10 M solution of NaCl will contain twice as many solute particles as a 0.10 M solution of methanol, which does not dissociate into ions.

Question 5

What volume of 12 M HCl solution needs to be diluted to produce 500 mL of 3.0 M HCl solution?

Accepted Answer

Using the dilution formula M1V1 = M2V2, where M1 is the initial molarity (12 M), V1 is the volume to find, M2 is the final molarity (3.0 M), and V2 is the final volume (500 mL). Solving for V1 gives V1 = (3.0 M * 500 mL) / 12 M = 125 mL.

Question 6

What volume of 0.25 M hydrochloric acid (HCl) solution contains Avogadro's number of Cl ^-ions?

Accepted Answer

The answer of What volume of 0.25 M hydrochloric acid...

Question 7

How many grams of sodium chloride, NaCl, are needed to make up 1.00 L of a solution that is 2.00 M?

Accepted Answer

To find the grams of NaCl needed, use the formula: grams = molarity (M) x molar mass x volume (L). The molar mass of NaCl is 58.44 g/mol. For a 2.00 M solution in 1.00 L, the calculation is 2.00 mol/L x 58.44 g/mol x 1.00 L = 116.88 g, which rounds to 117 g.

Question 8

If 50.0 mL of a 0.10 M solution of sodium chloride is mixed with 50.0 mL of 0.10 M magnesium chloride, what is the molar concentration of chloride in the resulting solution?

Accepted Answer

The answer of If 50.0 mL of a 0.10 M...

Question 9

Commercial hydrochloric acid is 12.1 M. What volume of commercial HCl solution should be used to prepare 250.0 mL of 3.00 M HCl?

Accepted Answer

The answer of Commercial hydrochloric acid is 12.1 M. What...

Question 10

In a demonstration of strong electrolytes, weak electrolytes, and nonelectrolytes, Professor Popsnorkle used a lightbulb apparatus that showed how much a solution conducted electricity by the brightness of the lightbulb. When pure water was tested, the bulb did not light. Then Professor Popsnorkle tested the following aqueous solutions. Which one caused the bulb to burn the brightest?

Accepted Answer

Table salt, NaCl, is a strong electrolyte, meaning it completely dissociates into ions in water and creates a high concentration of ions, leading to a strong conductance of electricity and a bright lightbulb. Ethanol, table sugar, acetic acid, and methanol are all weak electrolytes or nonelectrolytes, meaning they do not completely dissociate into ions and do not create a high concentration of ions, leading to a weaker conductance of electricity and a dimmer lightbulb.

Question 11

If the molar concentration of sodium sulfate (Na₂SO₄) is 0.10 M, what is the concentration of sodium ion?

Accepted Answer

Sodium sulfate (Na2SO4) dissociates in water to form 2 sodium ions (Na+) and 1 sulfate ion (SO4^2-). Therefore, a 0.10 M solution of sodium sulfate will produce a 0.20 M concentration of sodium ions because each formula unit of sodium sulfate produces two sodium ions upon dissociation.

Question 12

What volume of 3.0 M NaOH contains 0.15 mole of NaOH?

Accepted Answer

The formula to calculate volume is:

Volume (in Liters) = Number of moles / Molarity

Number of moles of NaOH = 0.15 mole
Molarity of NaOH solution = 3.0 M

So, volume of NaOH solution = 0.15 mole / 3.0 M = 0.05 L

Convert Liters to milliliters by multiplying by 1000:

Volume of NaOH solution = 0.05 L * 1000 mL/L = 50 mL

Therefore, the answer is option B (50 mL).

Question 13

If 100 mL of 3.0 M solution were diluted to 250 mL, what would the concentration be?

Accepted Answer

The concentration after dilution can be calculated using the formula $C_1V_1 = C_2V_2$, where $C_1$ and $C_2$ are the initial and final concentrations, and $V_1$ and $V_2$ are the initial and final volumes. Substituting the given values: $3.0\,M \times 100\,mL = C_2 \times 250\,mL$. Solving for $C_2$ gives $C_2 = 1.2\,M$.

Question 14

A salt solution is added to a marine aquarium. What mass of sodium chloride (58.44 g/mol) is needed to produce 250.0 mL of a solution that has a concentration of 0.0500 M ?

Accepted Answer

The answer of A salt solution is added to a...

Question 15

A standard adult dose of a cough suppressant is 15.0 mL. This portion contains 5.00 mg of the active ingredient. A pediatrician suggests that this medication can be given to children over the age of 6 years, but only if it is diluted so the dose is 1.00 mg in 20.0 mL. How many milliliters of the adult medicine would you need to use to make 100.0 mL of the child-strength cough suppressant?

Accepted Answer

The answer of A standard adult dose of a cough...

Question 16

What is the molar concentration of sodium ions in a 0.3 M sodium phosphate (Na₃PO₄, 164 g/mol) solution? Sodium phosphate is used as a cleaning agent, food additive, and stain remover.

Accepted Answer

Sodium phosphate (Na3PO4) dissociates in water to form three sodium ions (Na+) and one phosphate ion (PO4^3-). Therefore, for every 1 mole of sodium phosphate that dissolves, 3 moles of sodium ions are produced. Given a 0.3 M solution of sodium phosphate, the concentration of sodium ions will be 0.3 M * 3 = 0.9 M.

Question 17

In a demonstration of strong electrolytes, weak electrolytes, and nonelectrolytes, Professor Popsnorkle used a lightbulb apparatus that showed how much a solution conducted electricity by the brightness of the lightbulb. When pure water was tested, the bulb did not light. When some acetic acid was added to the water, the bulb burned dimly. When more acetic acid was added to the solution, the bulb burned a little more brightly. In his frustration to make the bulb shine brightly with acetic acid, Professor Popsnorkle started over by testing the beaker of the pure acetic acid. What was the result?

Accepted Answer

Pure acetic acid is a weak electrolyte because it does not dissociate completely in water. However, in its pure form, without water to facilitate the ionization process, it hardly conducts electricity at all, hence the bulb would not light.

Question 18

Which picture best represents an atomic-level view of a nonelectrolyte solution (water molecules not shown)?

Accepted Answer

The answer of Which picture best represents an atomic-level view...

Question 19

What volume of 0.25 M hydrochloric acid (HCl) solution contains 0.15 mol HCl?

Accepted Answer

To find the volume of solution that contains 0.15 mol of HCl when the concentration is 0.25 M, use the formula: volume = moles / concentration. Thus, volume = 0.15 mol / 0.25 M = 0.6 L, which is 600 mL.

Question 20

In the dilution of 10.0 mL of a 0.10 M solution of HCl to a volume of 20.0 mL, what remains unchanged?

Accepted Answer

The answer of In the dilution of 10.0 mL of...

Quiz 4: Solution Chemistry: The Hydrosphere

The World Health Organization recommends that the maximum allowable concentration of chromium(VI) in drinking water be limited to 0.05 mg/L. If the molar absorptivity of chromium(VI) at 345 nm is 1.5*10³/(M cm) , what is the absorbance of a solution that contains 0.050 mg/L in a 10-cm-long cell?

Diluting 1.0 mL of a 1.0 M solution to 1,000 mL results in a solution that is 0.001 M. Repeating this 1,000-fold dilution process five more times results in a concentration of __________

Which contains more solute particles: a 0.10 M aqueous solution of methanol (CH₃OH) or a 0.10 M aqueous solution of salt (NaCl) ?

What volume of 12 M HCl solution needs to be diluted to produce 500 mL of 3.0 M HCl solution?

What volume of 0.25 M hydrochloric acid (HCl) solution contains Avogadro's number of Cl ^-ions?

How many grams of sodium chloride, NaCl, are needed to make up 1.00 L of a solution that is 2.00 M?

If 50.0 mL of a 0.10 M solution of sodium chloride is mixed with 50.0 mL of 0.10 M magnesium chloride, what is the molar concentration of chloride in the resulting solution?

Commercial hydrochloric acid is 12.1 M. What volume of commercial HCl solution should be used to prepare 250.0 mL of 3.00 M HCl?

If the molar concentration of sodium sulfate (Na₂SO₄) is 0.10 M, what is the concentration of sodium ion?

What volume of 3.0 M NaOH contains 0.15 mole of NaOH?

If 100 mL of 3.0 M solution were diluted to 250 mL, what would the concentration be?

A salt solution is added to a marine aquarium. What mass of sodium chloride (58.44 g/mol) is needed to produce 250.0 mL of a solution that has a concentration of 0.0500 M ?

What is the molar concentration of sodium ions in a 0.3 M sodium phosphate (Na₃PO₄, 164 g/mol) solution? Sodium phosphate is used as a cleaning agent, food additive, and stain remover.

Which picture best represents an atomic-level view of a nonelectrolyte solution (water molecules not shown) ?

What volume of 0.25 M hydrochloric acid (HCl) solution contains 0.15 mol HCl?

In the dilution of 10.0 mL of a 0.10 M solution of HCl to a volume of 20.0 mL, what remains unchanged?

Quiz 4: Solution Chemistry: The Hydrosphere

The World Health Organization recommends that the maximum allowable concentration of chromium(VI) in drinking water be limited to 0.05 mg/L. If the molar absorptivity of chromium(VI) at 345 nm is 1.5*103/(M cm) , what is the absorbance of a solution that contains 0.050 mg/L in a 10-cm-long cell?

Diluting 1.0 mL of a 1.0 M solution to 1,000 mL results in a solution that is 0.001 M. Repeating this 1,000-fold dilution process five more times results in a concentration of __________

Which contains more solute particles: a 0.10 M aqueous solution of methanol (CH3OH) or a 0.10 M aqueous solution of salt (NaCl) ?

What volume of 12 M HCl solution needs to be diluted to produce 500 mL of 3.0 M HCl solution?

What volume of 0.25 M hydrochloric acid (HCl) solution contains Avogadro's number of Cl - ions?

How many grams of sodium chloride, NaCl, are needed to make up 1.00 L of a solution that is 2.00 M?

If 50.0 mL of a 0.10 M solution of sodium chloride is mixed with 50.0 mL of 0.10 M magnesium chloride, what is the molar concentration of chloride in the resulting solution?

Commercial hydrochloric acid is 12.1 M. What volume of commercial HCl solution should be used to prepare 250.0 mL of 3.00 M HCl?

If the molar concentration of sodium sulfate (Na2SO4) is 0.10 M, what is the concentration of sodium ion?

What volume of 3.0 M NaOH contains 0.15 mole of NaOH?

If 100 mL of 3.0 M solution were diluted to 250 mL, what would the concentration be?

A salt solution is added to a marine aquarium. What mass of sodium chloride (58.44 g/mol) is needed to produce 250.0 mL of a solution that has a concentration of 0.0500 M ?

What is the molar concentration of sodium ions in a 0.3 M sodium phosphate (Na3PO4, 164 g/mol) solution? Sodium phosphate is used as a cleaning agent, food additive, and stain remover.

Which picture best represents an atomic-level view of a nonelectrolyte solution (water molecules not shown) ?

What volume of 0.25 M hydrochloric acid (HCl) solution contains 0.15 mol HCl?

In the dilution of 10.0 mL of a 0.10 M solution of HCl to a volume of 20.0 mL, what remains unchanged?

The World Health Organization recommends that the maximum allowable concentration of chromium(VI) in drinking water be limited to 0.05 mg/L. If the molar absorptivity of chromium(VI) at 345 nm is 1.5*10³/(M cm) , what is the absorbance of a solution that contains 0.050 mg/L in a 10-cm-long cell?

Which contains more solute particles: a 0.10 M aqueous solution of methanol (CH₃OH) or a 0.10 M aqueous solution of salt (NaCl) ?

What volume of 0.25 M hydrochloric acid (HCl) solution contains Avogadro's number of Cl ^-ions?

If the molar concentration of sodium sulfate (Na₂SO₄) is 0.10 M, what is the concentration of sodium ion?

What is the molar concentration of sodium ions in a 0.3 M sodium phosphate (Na₃PO₄, 164 g/mol) solution? Sodium phosphate is used as a cleaning agent, food additive, and stain remover.