Question 1

Which of the following prefixes represents a multiplier of $10^{-6}$?

Accepted Answer

micro

Question 2

What is the SI base unit for measuring mass?

Accepted Answer

kilogram

Question 3

A sample contains $6.022 	imes 10^{23}$ molecules of water. What is the mass of this sample in grams? (Molar mass of water = $18.02$ g/mol)

Accepted Answer

$18.02$ g

Question 4

Which of the following numbers has 4 significant figures?

Accepted Answer

0.004560

Question 5

A lake has a surface area of $100$ mi$^2$ and an average depth of $20$ ft. If the lake is polluted with $0.4$ 	extmu g Hg/mL, what is the total mass of mercury in kg in the lake? (1 mi$^2$ = $2.59 	imes 10^6$ m$^2$, 1 ft = $0.3048$ m, 1 mL = $1 	imes 10^{-3}$ L, 1 L = $1 	imes 10^{-3}$ m$^3$)

Accepted Answer

$2.98 	imes 10^2$ kg

Question 6

Which statement best describes the difference between accuracy and precision?

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other.

Question 7

A student measures the mass of a sample as $24.1$ g and multiplies it by $300$. How many significant figures should the answer have?

Accepted Answer

1

Question 8

Which of the following is an example of a defined conversion with infinite significant figures?

Accepted Answer

$1$ inch = $2.54$ cm

Question 9

Calculate the percent by mass of nitrogen in ammonium nitrate, $NH_4NO_3$. (Molar mass: N = $14.01$ g/mol, H = $1.01$ g/mol, O = $16.00$ g/mol)

Accepted Answer

$35.00\%$

Question 10

A sample contains $9.541 	imes 10^{21}$ atoms of oxygen. How many mg of $Cr_2(CO_3)_3$ must there be? (Molar mass of $Cr_2(CO_3)_3$ = $284.02$ g/mol)

Accepted Answer

$4.50$ mg

Question 11

Which of the following is the correct empirical formula for benzene ($C_6H_6$)?

Accepted Answer

$CH$

Question 12

A student adds $73.64$ and $1.5$ and $71.8$. What is the correct answer with the proper number of significant figures?

Accepted Answer

$147$

Question 13

Which of the following best explains why the atomic mass of Fe on the periodic table is not exactly $56.9354$ g/mol?

Accepted Answer

It is a weighted average of the masses of all naturally occurring isotopes.

Question 14

Which of the following conversions is correct for $0.0000071$ sec using scientific notation?

Accepted Answer

$7.1 	imes 10^{-6}$ s

Question 15

If a bundle of No. 2 pencils weighs $27,950$ g and each pencil weighs $5.6$ g, how many pencils are in the bundle?

Accepted Answer

$5,000$

Question 16

Which of the following is the correct molar mass for $CCl_2F_2$?

Accepted Answer

$120.91$ g/mol

Question 17

Which of the following statements about significant figures is FALSE?

Accepted Answer

All zeros in any number are always significant.

Question 18

A blood sample analyzed in four labs gives the following cholesterol results: 100, 175, 200, 125 mg/dL (average = 150). Is this set of results accurate, precise, both, or neither?

Accepted Answer

Neither accurate nor precise

Question 19

Which of the following is the correct percent composition of phosphorus in $P_2O_5$? (Molar mass: P = $30.97$ g/mol, O = $16.00$ g/mol)

Accepted Answer

$43.64\%$

General Chemistry Study Notes: Measurement, Units, Moles, and Chemical Formulas

Study Guide - Practice Questions

Study Guide - Flashcards