Question 1

Which of the following elements is a Group 1 alkali metal located in the 3rd period of the periodic table?

Accepted Answer

Sodium

Question 2

A student has a 0.500 g sample of $t$-butyl alcohol ($C_4H_{10}O$). If the molar mass of $t$-butyl alcohol is $74.1224 \ \mathrm{g/mol}$, how many moles are present in the sample?

Accepted Answer

$0.00675 \ \mathrm{mol}$

Question 3

Which of the following best describes the Law of Constant Composition?

Accepted Answer

A chemical compound always contains the same proportion of elements by mass.

Question 4

Given the following reaction: $3\mathrm{Mg}_3\mathrm{N}_2 + 6\mathrm{H}_2\mathrm{O} \rightarrow 3\mathrm{Mg}(\mathrm{OH})_2 + 2\mathrm{NH}_3$, how many grams of $\mathrm{Mg}(\mathrm{OH})_2$ (molar mass $58.3197 \ \mathrm{g/mol}$) can be produced from $0.100 \ \mathrm{g}$ of $\mathrm{Mg}_3\mathrm{N}_2$ (molar mass $100.928 \ \mathrm{g/mol}$)?

Accepted Answer

$0.173 \ \mathrm{g}$

Question 5

A sample of Comol contains $71\%$ iron, $12\%$ cobalt, and $17\%$ holmium by mass. If a student obtains a $250.0 \ \mathrm{g}$ sample, how many grams of cobalt are present?

Accepted Answer

$30.0 \ \mathrm{g}$

Question 6

Which of the following is a correct balanced chemical equation for the reaction of magnesium nitride with water to produce magnesium hydroxide and ammonia?

Accepted Answer

$\mathrm{Mg}_3\mathrm{N}_2 + 6\mathrm{H}_2\mathrm{O} \rightarrow 3\mathrm{Mg}(\mathrm{OH})_2 + 2\mathrm{NH}_3$

Question 7

A $250.0 \ \mathrm{g}$ sample of Comol contains $12\%$ cobalt by mass. How many moles of cobalt atoms are present? (Molar mass of Co = $58.933 \ \mathrm{g/mol}$)

Accepted Answer

$0.509 \ \mathrm{mol}$

Question 8

Rubidium has two naturally occurring isotopes: $^{85}\mathrm{Rb}$ (atomic mass $84.9117$ u, abundance $72.17\%$) and $^{87}\mathrm{Rb}$ (atomic mass $86.9091$ u, abundance $27.83\%$). What is the atomic weight of rubidium?

Accepted Answer

$85.47$ u

Question 9

Which of the following is a correct formula for an oxide of chromium with a formula weight of approximately $100.0 \ \mathrm{amu}$? (Atomic masses: Cr = $51.9961$, O = $15.9994$)

Accepted Answer

$\mathrm{CrO}_3$

Question 10

A $10.0 \ \mathrm{mL}$ sample of $t$-butyl alcohol has a density of $0.810 \ \mathrm{g/mL}$. What is the mass of the sample?

Accepted Answer

$8.10 \ \mathrm{g}$

Question 11

Which of the following elements is a noble gas at room temperature?

Accepted Answer

Neon

Question 12

A vinegar sample contains $5.0\%$ by mass acetic acid ($\mathrm{CH}_3\mathrm{COOH}$). If the density of vinegar is $1.00 \ \mathrm{g/mL}$, what mass of acetic acid is present in $100.0 \ \mathrm{mL}$ of vinegar?

Accepted Answer

$5.0 \ \mathrm{g}$

Question 13

The speed of sound at $1000 \ \mathrm{m}$ and standard pressure is $336.43 \ \mathrm{m/s}$. Convert this speed to miles per hour. ($1 \ \mathrm{mile} = 1.609 \ \mathrm{km}$)

Accepted Answer

$752.5 \ \mathrm{miles/hour}$

Question 14

Which of the following is a metalloid?

Accepted Answer

Silicon

Question 15

How many hydrogen atoms are present in $0.674 \ \mathrm{g}$ of $t$-butyl alcohol ($C_4H_{10}O$)? (Molar mass $= 74.1224 \ \mathrm{g/mol}$, Avogadro's number $= 6.022 	imes 10^{23}$)

Accepted Answer

$5.48 	imes 10^{22}$

Question 16

Which of the following is a correct statement about cobalt?

Accepted Answer

Cobalt is a good conductor of electricity.

Question 17

A $250.0 \ \mathrm{g}$ sample of Comol contains $17\%$ holmium by mass. How many holmium atoms are present? (Molar mass of Ho = $164.930 \ \mathrm{g/mol}$, Avogadro's number $= 6.022 	imes 10^{23}$)

Accepted Answer

$1.55 	imes 10^{23}$

Question 18

Which of the following is a correct definition of a diatomic element?

Accepted Answer

An element that exists as molecules composed of two atoms.

Question 19

Which of the following is a correct statement about the oxidation number of sulfur in $\mathrm{SO}_2$?

Accepted Answer

$+4$

Question 20

A $100.0 \ \mathrm{mL}$ sample of vinegar contains $5.0\%$ acetic acid by mass. If the density of vinegar is $1.00 \ \mathrm{g/mL}$, how many moles of acetic acid ($\mathrm{CH}_3\mathrm{COOH}$, molar mass $60.052 \ \mathrm{g/mol}$) are present?

Accepted Answer

$0.0833 \ \mathrm{mol}$

General Chemistry: Atomic Structure, Periodic Table, Stoichiometry, and Dimensional Analysis

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