Q: A patient receives a dose of medication that is 0.250 mol. If the molar mass of the medication is 180 g/mol, what mass of medication did the patient receive?

$$0.250\ \mathrm{mol} \times 180\ \mathrm{g/mol} = 45\ \mathrm{g}$$

Question 1

Which of the following statements best describes a compound?

Accepted Answer

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

Question 2

A student measures the mass of a metal block as 45.67 g and its volume as 16.2 mL. What is the density of the block, reported with the correct number of significant figures?

Accepted Answer

$$d = \frac{45.67\ \mathrm{g}}{16.2\ \mathrm{mL}} = 2.82\ \mathrm{g/mL}$$

Question 3

Which of the following is NOT an SI base unit?

Accepted Answer

Gram

Question 4

Which of the following best explains why ionic bonds typically form between metals and nonmetals?

Accepted Answer

Metals tend to lose electrons and nonmetals tend to gain electrons, resulting in electron transfer.

Question 5

A sample of gas has a mass of 0.250 kg and occupies a volume of 0.500 m$$^3. $$What is its density in kg/m$$^3$$?

Accepted Answer

$$d = \frac{0.250\ \mathrm{kg}}{0.500\ \mathrm{m}^3} = 0.50\ \mathrm{kg/m}^3$$

Question 6

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element consists of only one type of atom, while a compound contains two or more different elements chemically combined.

Question 7

Which of the following measurements contains the correct number of significant figures?

Accepted Answer

1.230 has 4 significant figures.

Question 8

A chemist mixes two colorless solutions and observes the formation of a white solid. Which of the following best explains what has occurred?

Accepted Answer

A chemical change has occurred, resulting in the formation of a new compound (precipitate).

Question 9

Which of the following best describes the arrangement of subatomic particles in an atom?

Accepted Answer

Protons and neutrons are in the nucleus; electrons orbit the nucleus.

Question 10

Which of the following is an example of a covalent compound?

Accepted Answer

CO$$_2$$

Question 11

A patient receives a dose of medication that is 0.250 mol. If the molar mass of the medication is 180 g/mol, what mass of medication did the patient receive?

Accepted Answer

$$0.250\ \mathrm{mol} 	imes 180\ \mathrm{g/mol} = 45\ \mathrm{g}$$

Question 12

Which of the following best describes the periodic table's organization?

Accepted Answer

By increasing atomic number.

Question 13

A student records the following measurements: 2.50 m, 0.0030 kg, and 4.00 s. Which SI base units are represented?

Accepted Answer

Meter, kilogram, second

Question 14

Which of the following best explains why water (H$$_2O) is $$considered a pure substance?

Accepted Answer

It has a fixed composition and distinct properties.

Question 15

A sample of ethanol has a mass of 78.5 g and a volume of 100.0 mL. What is its density in g/mL?

Accepted Answer

$$d = \frac{78.5\ \mathrm{g}}{100.0\ \mathrm{mL}} = 0.785\ \mathrm{g/mL}$$

Question 16

Which of the following is a correct statement about significant figures in the measurement 0.00450?

Accepted Answer

It has 3 significant figures.

Question 17

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

Accepted Answer

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

Question 18

Which of the following is the correct formula for density?

Accepted Answer

$$d = \frac{m}{V}$$

Question 19

A student is asked to identify a sample as an element, compound, or mixture. The sample cannot be separated by physical means, but can be decomposed into simpler substances by chemical means. What is the sample?

Accepted Answer

Compound

Question 20

Which of the following best describes the role of the mole in chemistry?

Accepted Answer

It is the SI unit for the amount of substance, representing $$6.022 	imes 10$$^{23}$$ entities.

Matter, Measurements, and Basic Chemical Concepts

Guida di studio - Domande di pratica

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