Q: A sample contains 0.250 mol of glucose (C6H12O6). How many oxygen atoms are present in this sample?

$$0.250 \times 6 \times 6.022 \times 10$$^{23}$$ atoms

Q: A gas occupies 2.0 L at 1.0 atm and 300 K. What will its volume be at 2.0 atm and 400 K? (Use the combined gas law.)

$$V_2$$ = \frac{(1.0)(2.0)}{300} \times \frac{400}{2.0} = 1.33\ \mathrm{L}$$

Question 1

A sample contains 0.250 mol of glucose (C6H12O6). How many oxygen atoms are present in this sample?

Accepted Answer

$$0.250 	imes 6 	imes 6.022 	imes 10$$^{23}$$ atoms

Question 2

Which of the following best explains why gases are compressible, while solids are not?

Accepted Answer

Gas particles are much farther apart than solid particles, allowing them to be pushed closer together.

Question 3

A 0.20 M solution of CaCl$$_2 is $$prepared. What is the concentration of chloride ions in the solution?

Accepted Answer

$$0.40\ \mathrm{M}$$

Question 4

Which of the following is a correct application of the Law of Conservation of Mass in a chemical reaction?

Accepted Answer

The total mass of reactants equals the total mass of products in a closed system.

Question 5

Which of the following compounds exhibits hydrogen bonding as its strongest intermolecular force?

Accepted Answer

NH$$_3$$

Question 6

A 5.0 g sample of NaCl is dissolved in enough water to make 100.0 g of solution. What is the mass percent concentration of NaCl?

Accepted Answer

$$5.0\%$$

Question 7

Which of the following best describes a double displacement (replacement) reaction?

Accepted Answer

Two compounds exchange ions to form two new compounds.

Question 8

A gas occupies 2.0 L at 1.0 atm and 300 K. What will its volume be at 2.0 atm and 400 K? (Use the combined gas law.)

Accepted Answer

$$V_2$$ = \frac{(1.0)(2.0)}{300} 	imes \frac{400}{2.0} = 1.33\ \mathrm{L}$$

Question 9

Which of the following statements about strong acids is correct?

Accepted Answer

Strong acids completely ionize in water.

Question 10

A solution has a pH of 3.25. What is the hydronium ion concentration $$[\mathrm{H}_3\mathrm{O}^+]$$?

Accepted Answer

$$[\mathrm{H}_3\mathrm{O}^+] = 10$$^{-3.25}$$\ \mathrm{M}$$

Question 11

Which of the following best describes the difference between an Arrhenius base and a Bronsted-Lowry base?

Accepted Answer

An Arrhenius base produces OH$$^- in $$water, while a Bronsted-Lowry base accepts H$$^+.$$

Question 12

A 0.50 mol sample of NaOH is dissolved to make 2.0 L of solution. What is the molarity of the solution?

Accepted Answer

$$0.25\ \mathrm{M}$$

Question 13

Which of the following is a property of a solution that contains a non-electrolyte solute?

Accepted Answer

It does not conduct electricity because the solute does not form ions.

Question 14

Which of the following best explains why heating a gas increases its pressure (if volume is constant)?

Accepted Answer

The average kinetic energy of gas particles increases, causing more frequent and forceful collisions with the container walls.

Question 15

A student wants to prepare 100.0 mL of a 0.50 M NaCl solution from a 2.0 M stock solution. What volume of the stock solution should be used?

Accepted Answer

$$25.0\ \mathrm{mL}$$

Question 16

Which of the following is the correct balanced equation for the reaction: sodium chloride solution reacts with silver nitrate solution to form silver chloride solid and sodium nitrate solution?

Accepted Answer

$$\mathrm{NaCl}(aq) + \mathrm{AgNO}_3(aq) \rightarrow \mathrm{AgCl}(s) + \mathrm{NaNO}_3(aq)$$

Question 17

A solution has $$[\mathrm{OH}^-] = 1.0 	imes 10$$^{-5}$$\ \mathrm{M}. $$What is the pH of the solution at 25$$^\circC$$?

Accepted Answer

$$pH = 9$$

Question 18

Which of the following best describes a supersaturated solution?

Accepted Answer

It contains more dissolved solute than is normally possible at that temperature.

Question 19

Which of the following is the correct molar mass of H$$_2SO$_4 ($$sulfuric acid)? (Atomic masses: H = 1.01, S = 32.07, O = 16.00)

Accepted Answer

$$2(1.01) + 32.07 + 4(16.00) = 98.09\ \mathrm{g/mol}$$

Introductory Chemistry Study Notes: Chemical Composition, Reactions, Gases, Solutions, and Acids/Bases

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