Question 1

Which of the following statements best describes the process of dilution in solution chemistry?

Accepted Answer

Dilution involves adding more solvent to a solution, resulting in a decrease in concentration but the same number of solute particles.

Question 2

If you have 25.0 mL of 0.450 mol L$$^{-1}$$ CaCl$$_2$$ solution and it reacts completely with excess AgNO$$_3$$, what mass of AgCl (molar mass = 143.4 g mol$$^{-1}) $$will precipitate? (Reaction: CaCl$$_2(aq) + 2$$AgNO$$_3(aq$$) → 2AgCl(s) + Ca(NO$$_3$$)$$_2(aq))$$

Accepted Answer

$$3.23 g$$

Question 3

A student dilutes 10.0 mL of 1.2 mol L$$^{-1}$$ HCl by adding it to 5.00 mL of water. What is the final concentration of HCl in the resulting solution?

Accepted Answer

$$0.400$$ mol L$$^{-1}$$

Question 4

Which equation correctly relates the concentrations and volumes before and after dilution?

Accepted Answer

$$c_1V_1 = c_2V_2$$

Question 5

You are asked to prepare 100.0 mL of 0.500 mol L$$^{-1}$$ HCl by diluting a stock solution. If you start with 5.00 mL of the stock solution, what is the concentration of the resulting solution after adding 95.0 mL of water?

Accepted Answer

$$0.0250$$ mol L$$^{-1}$$

Question 6

A laboratory technician needs to prepare 5.00 L of 1.50 mol L$$^{-1} H$_2SO$_4$$ from an 18.4 mol L$$^{-1}$$ stock solution. What volume of the stock solution is required?

Accepted Answer

$$0.408 L$$

Question 7

What is the concentration in ppm of a 0.00200 mol L$$^{-1}$$ NaCl solution? (Molar mass of NaCl = 58.5 g mol$$^{-1}$$, density of solution = 1.00 g mL$$^{-1})$$

Accepted Answer

$$117$$ ppm

Question 8

Which of the following best explains why the number of moles of solute does not change during dilution?

Accepted Answer

Because only the volume of solvent changes, not the amount of solute.

Question 9

A solution is prepared by dissolving 2.36 g of CuCO$$_3 ($$molar mass = 123.5 g mol$$^{-1}) in 25.0 mL of $$solution. What is the concentration of CuCO$$_3 in $$mol L$$^{-1}$$?

Accepted Answer

$$0.764$$ mol L$$^{-1}$$

Question 10

Which of the following is a correct step in calculating the new concentration after dilution?

Accepted Answer

Divide the initial moles of solute by the final volume.

Question 11

A chemist needs to prepare 250 mL of 0.100 mol L$$^{-1}$$ NaOH from a 2.00 mol L$$^{-1}$$ stock solution. What volume of the stock solution should be used?

Accepted Answer

$$12.5 mL$$

Question 12

Which of the following best describes the relationship between concentration and volume during dilution, assuming the amount of solute remains constant?

Accepted Answer

Concentration is inversely proportional to volume.

Question 13

A 0.0250 mol sample of NaCl is dissolved in enough water to make 500 mL of solution. What is the concentration of NaCl in mol L$$^{-1}$$?

Accepted Answer

$$0.0500$$ mol L$$^{-1}$$

Question 14

If 10.0 mL of a 2.00 mol L$$^{-1}$$ solution is diluted to a final volume of 100.0 mL, what is the new concentration?

Accepted Answer

$$0.200$$ mol L$$^{-1}$$

Question 15

A solution contains 0.500 mol of solute in 2.00 L of solution. What is its concentration in mol L$$^{-1}$$?

Accepted Answer

$$0.250$$ mol L$$^{-1}$$

Question 16

Which of the following is a real-world application of dilution calculations?

Accepted Answer

Preparing intravenous (IV) solutions in hospitals to ensure correct drug dosage.

Question 17

A 0.100 mol L$$^{-1}$$ solution of HCl is prepared by diluting a more concentrated stock solution. If 20.0 mL of the stock solution is diluted to 200.0 mL, what was the concentration of the stock solution?

Accepted Answer

$$1.00$$ mol L$$^{-1}$$

Solutions and Dilution Calculations in Chemistry

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