Q: A sample contains $$ 3.0 \ \mathrm{mol} of a $$substance. How many particles does it contain? (Avogadro's number $$ = 6.022 \times 10$$^{23}$$ $$ particles/mol)

$$ 1.81 \times 10$$^{24}$$ $$ particles

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in a fixed ratio.

Question 2

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements are arranged by increasing atomic number.

Question 3

A student measures the mass of a metal block as $$ 45.67 \ \mathrm{g} $$ and its volume as $$ 16.2 \ \mathrm{cm}^3 . $$What is the density of the metal, reported with the correct number of significant figures?

Accepted Answer

$$ 2.82 \ \mathrm{g/cm}^3 $$

Question 4

Which of the following is an example of an ionic bond?

Accepted Answer

The bond between sodium and chlorine in $$ \mathrm{NaCl} $$

Question 5

Which SI unit would you use to measure the amount of a substance in a chemical reaction?

Accepted Answer

Mole

Question 6

A sample of gas has a mass of $$ 0.500 \ \mathrm{g} $$ and occupies a volume of $$ 250.0 \ \mathrm{mL} . $$What is its density in $$ \mathrm{g/mL} $$?

Accepted Answer

$$ 0.0020 \ \mathrm{g/mL} $$

Question 7

Which of the following best explains why water ($$ \mathrm{H}_2\mathrm{O} ) is $$considered a pure substance?

Accepted Answer

It has a fixed composition and distinct chemical properties.

Question 8

A chemist needs to measure the temperature change in a reaction. Which SI unit should be used?

Accepted Answer

Kelvin

Question 9

Which of the following statements about atoms is correct?

Accepted Answer

Protons and neutrons are found in the nucleus.

Question 10

A student records the following measurements: $$ 12.0 \ \mathrm{g} $$, $$ 12.00 \ \mathrm{g} $$, and $$ 12 \ \mathrm{g} . $$Which measurement has the greatest number of significant figures?

Accepted Answer

$$ 12.00 \ \mathrm{g} $$

Question 11

Which of the following is a real-life example of a covalent bond?

Accepted Answer

The bond between hydrogen and oxygen in water.

Question 12

A patient receives a saline solution containing $$ 0.90 \ \mathrm{g}  of$$ $$ \mathrm{NaCl} $$ dissolved in $$ 100.0 \ \mathrm{mL}  of $$water. What is the density of the solution if its total mass is $$ 100.90 \ \mathrm{g} $$? (Assume the volume is $$ 100.0 \ \mathrm{mL} .)$$

Accepted Answer

$$ 1.01 \ \mathrm{g/mL} $$

Question 13

Which of the following best describes the difference between a solid and a gas?

Accepted Answer

A solid has a fixed shape and volume, while a gas has neither.

Question 14

Which of the following is NOT an SI base unit?

Accepted Answer

Gram

Question 15

A sample contains $$ 3.0 \ \mathrm{mol}  of a $$substance. How many particles does it contain? (Avogadro's number $$ = 6.022 	imes 10$$^{23}$$ $$ particles/mol)

Accepted Answer

$$ 1.81 	imes 10$$^{24}$$ $$ particles

Question 16

Which of the following best explains why carbon dioxide ($$ \mathrm{CO}_2 ) is $$classified as a compound?

Accepted Answer

It can be separated into carbon and oxygen by chemical means.

Question 17

A laboratory technician needs to prepare $$ 250.0 \ \mathrm{mL}  of a $$solution with a density of $$ 1.10 \ \mathrm{g/mL} . $$What mass of solution should be prepared?

Accepted Answer

$$ 275 \ \mathrm{g} $$

Question 18

Which of the following is a correct statement about significant figures?

Accepted Answer

All nonzero digits are significant.

Question 19

Which of the following best describes the process of forming an ionic bond?

Accepted Answer

Electrons are transferred from a metal to a nonmetal.

Question 20

A student mixes $$ 25.0 \ \mathrm{g}  of $$ethanol ($$ \mathrm{C}_2\mathrm{H}_5\mathrm{OH} ) $$with $$ 50.0 \ \mathrm{g}  of $$water. Is the resulting mixture a pure substance or a mixture, and why?

Accepted Answer

A mixture, because the composition can vary.

Matter, Measurements, and Atomic Structure: General Chemistry Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드