Q: If the density of a certain spherical atomic nucleus is $$1.0 \times 10$$^{14}$$\ \mathrm{g\ cm$$^{-3}$$}$$ and its mass is $$2.0 \times 10$$^{-23}$$\ \mathrm{g}$$, what is its radius in cm? Use $$V_{\text{sphere}} = \frac{4}{3}\pi r^3$.

$$3.2 \times 10$$^{-13}$$\ \mathrm{cm}$$

Question 1

Which of the following statements about isotopes and ions is correct?
I. $$^{40}\mathrm{Ar}$$ and $$^{41}\mathrm{Ar}$$ have the same number of protons.
II. $$^{63}\mathrm{Cu}$$ and $$^{63}\mathrm{Zn}$$ have the same number of neutrons.
III. $$^{63}\mathrm{Cu}$$ and $$^{65}\mathrm{Ga}$$ have the same number of neutrons.
IV. $$^{63}\mathrm{Zn}$$ and $$^{65}\mathrm{Zn}$$ have the same number of electrons (as neutral atoms).
Which is correct?

Accepted Answer

Only II

Question 2

A student performs the following calculation: $$\frac{16.180 	imes 0.0916}{1.4783 	imes 0.213}$$ and $$35.3 + 98.1 - 3.21. $$What are the answers with the correct number of significant figures?

Accepted Answer

$$4.71$$; $$130.$$

Question 3

Which of the following formula and name pairs is correct?

Accepted Answer

PbO, lead(II) oxide

Question 4

Calculate the mass percent of oxygen in $$\mathrm{$$FeSO_4$$} \cdot 7 \mathrm{H_2O}.$$

Accepted Answer

$$45.3\%$$

Question 5

An aqueous solution contains bromide, fluoride, and sulfate ions. Adding which of the following will cause the precipitation of the bromide and sulfate ions, leaving the fluoride ions in solution?

Accepted Answer

Pb(NO$$_3$$)$$_2$$

Question 6

Which of the following has the greatest mass?

Accepted Answer

$$0.500$$ mol of O$$_2$$

Question 7

Calculate the molarity of sodium ions in the solution resulting from dissolving $$50.0 g of $$sodium carbonate in enough water to give a final volume of $$350.\ \mathrm{mL}$$, then mixing the solution with $$150.\ \mathrm{mL} of$$ $$0.500\ \mathrm{M}$$ sodium chloride solution.

Accepted Answer

$$1.09\ \mathrm{M}$$

Question 8

If the density of a certain spherical atomic nucleus is $$1.0 	imes 10$$^{14}$$\ \mathrm{g\ cm$$^{-3}$$}$$ and its mass is $$2.0 	imes 10$$^{-23}$$\ \mathrm{g}$$, what is its radius in cm? Use $$V_{	ext{sphere}} = \frac{4}{3}\pi r^3$.

Accepted Answer

$$3.2 	imes 10$$^{-13}$$\ \mathrm{cm}$$

Question 9

Copper has two naturally occurring isotopes, $$^{63}\mathrm{Cu} ($$isotopic mass $$62.9396$$ amu) and $$^{65}\mathrm{Cu} ($$isotopic mass $$64.9278$$ amu). The average atomic mass of copper is $$63.546$$ amu. What is the percent abundance of $$^{65}\mathrm{Cu} in a $$naturally occurring sample of copper?

Accepted Answer

$$30.7\%$$

Question 10

A hospitalized patient weighing $$70.0\ \mathrm{kg}$$ requires an antibiotic at a dose of $$2.59\ \mathrm{mg/lb}$$ every $$8$$ hours for $$10$$ days. The infusion solution contains $$400\ \mathrm{mg} of $$antibiotic per $$40\ \mathrm{mL} of $$solution. How many milliliters are required for the $$10-$$day treatment?

Accepted Answer

$$1200\ \mathrm{mL}$$

Question 11

The complete combustion of $$4.70 g of a $$hydrocarbon produced $$14.5 g of CO$_2$$ and $$6.67 g of H$_2O. $$What is the empirical formula for the hydrocarbon?

Accepted Answer

C$$_5H$_6$$

Question 12

How many grams of PI$$_3$$ could be produced from $$250. g of I$_2$$ and excess phosphorus if the reaction gives a $$98.5\%$$ yield? $$\mathrm{P_4$} + 6\mathrm{I_2$} \rightarrow 4\mathrm{PI_3$}$$

Accepted Answer

$$266 g$$

Question 13

Two reactions in sequence are needed to produce phosphoric acid from phosphorus:
$$\mathrm{P_4$} + 5\mathrm{O_2$} \rightarrow 2\mathrm{P_2O_5}$$
$$\mathrm{P_2O_5} + 3\mathrm{H_2O} \rightarrow 2\mathrm{H_3PO_4}$$
How many moles of $$\mathrm{P_4$}$$ must be used to produce $$12$$ moles of $$\mathrm{H_3PO_4}$$?

Accepted Answer

4 moles

Question 14

6.0 g each of iron and water is reacted according to this chemical equation: $$3\mathrm{Fe}(s) + 4\mathrm{H_2O}(l) \rightarrow \mathrm{Fe_3O_4}(s) + 4\mathrm{H_2$}(g). $$Which one of the following statements is FALSE?

Accepted Answer

Water is the limiting reactant.

Question 15

You perform a serial dilution beginning with $$50.0 mL of$$ $$2.00 M $$stock solution of NaCl. You take $$12.0 mL of $$the stock solution and add it to a $$200 mL $$volumetric flask, then fill it to a total solution volume of $$200 mL $$using water. You perform another dilution through which you obtain $$250 mL of$$ $$0.05 M $$NaCl solution. How many milliliters of the diluted solution did you use to make the final solution?

Accepted Answer

12.5 mL

Question 16

How many grams of NaH$$_2PO$_4$$ ($$119.98 g/$$mol) are needed to completely neutralize $$43.74 mL of$$ $$0.285 M $$NaOH?

Accepted Answer

1.21 g

Question 17

Which of the following reactions/combinations has the total ionic equation the same as the net ionic equation?
I. HCl(aq) + NaOH(aq)
II. Sr(OH)$$_2(aq) + H$_2SO$_4(aq)
$$III. HF(aq) + KOH(aq)

Accepted Answer

I only

Question 18

For the reaction $$\mathrm{Fe_2O_3}(s) + 3\mathrm{CO}(g) \rightarrow 2\mathrm{Fe}(s) + 3\mathrm{CO_2$}(g)$$, which of the following statements are true?
I. Fe$$_2O$_3 is $$the oxidizing agent.
II. The oxidation number of the carbon in CO$$_2 is$$ $$-4.
$$III. The iron in Fe$$_2O$_3 is $$oxidized.
IV. The reaction is a redox reaction.

Accepted Answer

3

Question 19

When $$5.0 g of an $$unknown gas is placed in a $$5.00 L $$container, the pressure is measured to be $$500$$ mmHg at $$50^\circC. $$Which of the following is the most likely identity of the gas?

Accepted Answer

O$$_2$$

Question 20

A molecule diffuses $$2$$ times faster than SO$$_2$$ under the same conditions. Which of the following could it be?

Accepted Answer

CH$$_4$$

General Chemistry Practice Exam 1 (Chapters 1-5) – Step-by-Step Study Guidance

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