Q: How many atoms of argon are present in $7.66 \times 10^5$ mmol of argon?

$1.15 \times 10^{28}\ \text{atoms}$

Q: How many zinc atoms are contained in $922\ \text{g}$ of Zn? (Molar mass of Zn = $65.38\ \text{g/mol}$, $N_A = 6.022 \times 10^{23}$)

$8.49 \times 10^{24}\ \text{atoms}$

Q: A sample contains $47.6\ \text{g}$ of $\mathrm{Al_2(CO_3)_3}$ (molar mass $= 233.99\ \text{g/mol}$). How many atoms of carbon are present?

$3.68 \times 10^{23}\ \text{C atoms}$

Question 1

An unknown element has three stable isotopes with masses of 27.977 amu, 28.976 amu, and 29.973 amu. The heavier two isotopes have abundances of 4.68% and 3.09%, respectively. What is the average atomic mass of this element?

Accepted Answer

$28.085\ 	ext{amu}$

Question 2

How many atoms of argon are present in $7.66 	imes 10^5$ mmol of argon?

Accepted Answer

$1.15 	imes 10^{28}\ 	ext{atoms}$

Question 3

A hospital uses krypton gas for MRI imaging. What mass (in grams) does $7.98$ moles of Kr have? (Molar mass of Kr = $83.80\ 	ext{g/mol}$)

Accepted Answer

$668\ 	ext{g}$

Question 4

How many zinc atoms are contained in $922\ 	ext{g}$ of Zn? (Molar mass of Zn = $65.38\ 	ext{g/mol}$, $N_A = 6.022 	imes 10^{23}$)

Accepted Answer

$8.49 	imes 10^{24}\ 	ext{atoms}$

Question 5

Calculate the molar mass of aluminum acetate, $\mathrm{Al(C_2H_3O_2)_3}$.

Accepted Answer

$204.13\ 	ext{g/mol}$

Question 6

A sample contains $47.6\ 	ext{g}$ of $\mathrm{Al_2(CO_3)_3}$ (molar mass $= 233.99\ 	ext{g/mol}$). How many atoms of carbon are present?

Accepted Answer

$3.68 	imes 10^{23}\ 	ext{C atoms}$

Question 7

A compound is found to be $70.79\%$ carbon, $8.91\%$ hydrogen, $4.59\%$ nitrogen, and $15.72\%$ oxygen by mass. What is its molecular formula?

Accepted Answer

$\mathrm{C_{18}H_{27}NO_3}$

Question 8

Which of the following is NOT an empirical formula?

Accepted Answer

$\mathrm{C_2H_6O_2}$

Question 9

A reaction produces $28.65\ 	ext{g}$ of Fe when $50.00\ 	ext{g}$ of $\mathrm{Fe_2O_3}$ reacts with excess Al: $\mathrm{Fe_2O_3(s) + 2Al(s) ightarrow Al_2O_3(s) + 2Fe(s)}$. What is the percent yield?

Accepted Answer

$61.03\ \%$

Question 10

Which of the following compounds is soluble in water?

Accepted Answer

$\mathrm{Ni(NO_3)_2}$

Question 11

A solution is prepared by dissolving $97.7\ 	ext{g}$ of LiBr in enough water to make $750.0\ 	ext{mL}$ of solution. What is the molarity of the solution? (Molar mass of LiBr = $86.85\ 	ext{g/mol}$)

Accepted Answer

$1.50\ 	ext{M}$

Question 12

What is the net ionic equation for the reaction between aqueous solutions of $\mathrm{K_2S}$ and $\mathrm{Fe(NO_3)_2}$?

Accepted Answer

$\mathrm{Fe^{2+}(aq) + S^{2-}(aq) \rightarrow FeS(s)}$

Question 13

How many milliliters of a $9.0\ 	ext{M}$ $\mathrm{H_2SO_4}$ solution are needed to make $0.45\ 	ext{L}$ of a $3.5\ 	ext{M}$ solution?

Accepted Answer

$180\ 	ext{mL}$

Question 14

Determine the oxidation state of sulfur in $\mathrm{K_2SO_4}$.

Accepted Answer

$+6$

Question 15

How many grams of NaCl are required to make $300.0\ 	ext{mL}$ of a $2.500\ 	ext{M}$ solution? (Molar mass of NaCl = $58.44\ 	ext{g/mol}$)

Accepted Answer

$43.83\ 	ext{g}$

Question 16

Which of the following best describes acetic acid ($\mathrm{CH_3COOH}$)?

Accepted Answer

weak electrolyte, weak acid

Question 17

A student dilutes $20.0\ 	ext{mL}$ of a $0.200\ 	ext{M}$ KCl solution to a final volume of $250.0\ 	ext{mL}$. What is the final concentration?

Accepted Answer

$0.0160\ 	ext{M}$

Question 18

Determine the oxidation state of titanium in $\mathrm{Ti(SO_4)_2}$.

Accepted Answer

$+4$

Question 19

Which of the following compounds is soluble in water according to the solubility rules?

Accepted Answer

$\mathrm{CaS}$

General Chemistry Exam 2 Study Guidance

Study Guide - Practice Questions

Study Guide - Flashcards