Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting in moist air

Question 2

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of carbon dioxide. How many moles of carbon dioxide are present?

Accepted Answer

$$0.50$$ mol

Question 3

Which of the following statements is consistent with Dalton’s atomic theory?

Accepted Answer

All atoms of a given element are identical in mass and properties.

Question 4

A compound contains $$40.0\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH}_2\mathrm{O}$$

Question 5

Which of the following is a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 6

A student measures the mass of a sample three times and records $$5.12 g$$, $$5.13 g$$, and $$5.11 g. $$The true mass is $$5.00 g. $$Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 7

Which of the following elements is a metalloid?

Accepted Answer

Silicon

Question 8

How many significant figures are in the measurement $$0.004560 g$$?

Accepted Answer

4

Question 9

Which of the following correctly represents the isotope with 17 protons, 18 neutrons, and 17 electrons?

Accepted Answer

$$^{35}\mathrm{Cl}$$

Question 10

What is the molar mass of calcium nitrate, $$\mathrm{Ca(NO_3$)_2}$$?

Accepted Answer

$$164.1 g/$$mol

Question 11

Which of the following is the correct name for $$\mathrm{$$FeCl_3$$}$$?

Accepted Answer

Iron(III) chloride

Question 12

A sample of glucose, $$\mathrm{C_6H_{12}O_6$}$$, contains $$0.10$$ mol. How many molecules are present?

Accepted Answer

$$6.02 	imes 10$$^{22}$$

Question 13

Which of the following is a physical property?

Accepted Answer

Density

Question 14

A compound is found to contain $$70.0\%$$ iron and $$30.0\%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{Fe_2O_3}$$

Question 15

Which of the following best describes the law of definite proportions?

Accepted Answer

A compound always contains the same elements in the same ratio by mass.

Question 16

How many atoms are in $$2.00$$ mol of helium gas?

Accepted Answer

$$1.20 	imes 10$$^{24}$$

Question 17

Which of the following is the correct formula for dinitrogen pentoxide?

Accepted Answer

$$\mathrm{N_2O_5}$$

Question 18

A student needs to convert $$25.0$$ inches to centimeters. (1 inch = 2.54 cm). What is the correct answer with the proper number of significant figures?

Accepted Answer

$$63.5 cm$$

Question 19

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 20

What is the percent composition by mass of hydrogen in water ($$\mathrm{H_2O}$$)?

Accepted Answer

$$11.2\%$$

General Chemistry Study Guide: Matter, Measurement, Atoms, and Molecules (Chapters 1–3)

Guida di studio - Domande di pratica

Study guide - Flashcard