Q: How many atoms are in $$2.00$$ moles of magnesium?

$$1.20 \times 10$$^{24}$$ atoms

Q: A photon has a wavelength of $$500\ \mathrm{nm}. $$What is its frequency? $$(c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$6.00 \times 10$$^{14}$$\ \mathrm{Hz}$$

Question 1

Which of the following statements correctly describes the three subatomic particles in an atom?

Accepted Answer

Protons have a positive charge, neutrons are neutral, and electrons have a negative charge.

Question 2

Which of the following is an example of isotopes?

Accepted Answer

$$^{12}\mathrm{C}$$ and $$^{14}\mathrm{C}$$

Question 3

Given an atom with 17 protons, 18 neutrons, and 17 electrons, which is the correct atomic symbol?

Accepted Answer

$$^{35}_{17}\mathrm{Cl}$$

Question 4

Which of the following best defines the atomic mass unit (amu)?

Accepted Answer

One twelfth the mass of a carbon-12 atom.

Question 5

Chlorine has two main isotopes: $$^{35}\mathrm{Cl} ($$mass = 34.97 amu, abundance = 75.77%) and $$^{37}\mathrm{Cl} ($$mass = 36.97 amu, abundance = 24.23%). What is the average atomic mass of chlorine?

Accepted Answer

$$35.45$$ amu

Question 6

Which of the following is the empirical formula for glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$)?

Accepted Answer

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

Question 7

Which statement best describes the periodic law?

Accepted Answer

The properties of elements are periodic functions of their atomic numbers.

Question 8

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting in moist air.

Question 9

Which property is intensive?

Accepted Answer

Density

Question 10

A student measures the mass of a sample as $$12.345 g $$and the volume as $$6.7 mL. $$What is the density, reported with the correct number of significant figures?

Accepted Answer

$$1.8 g/mL$$

Question 11

Convert $$25.0\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298.15\ \mathrm{K}$$

Question 12

How many atoms are in $$2.00$$ moles of magnesium?

Accepted Answer

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

Question 13

Which equation correctly relates the energy $$(E) of a $$photon to its frequency $$(
u)$$?

Accepted Answer

$$E = h
u$$

Question 14

A photon has a wavelength of $$500\ \mathrm{nm}. $$What is its frequency? $$(c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$6.00 	imes 10$$^{14}$$\ \mathrm{Hz}$$

Question 15

According to the Bohr model, what happens when an electron in a hydrogen atom moves from $$n=4 to$$ $$n=2$$?

Accepted Answer

A photon is emitted.

Question 16

Which set of quantum numbers is not allowed for an electron in an atom?

Accepted Answer

$$n=2,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 17

Which element is a metalloid?

Accepted Answer

Silicon

Question 18

Which of the following compounds contains an ionic bond?

Accepted Answer

$$\mathrm{NaCl}$$

Question 19

A sample of gas has a mass of $$4.00 g $$and occupies $$2.00 L at a $$certain temperature and pressure. What is the density of the gas?

Accepted Answer

$$2.00 g/L$$

Question 20

Which of the following is a physical property?

Accepted Answer

Boiling point

General Chemistry I: Foundations of Atomic Structure, Matter, and Measurement

Guida di studio - Domande di pratica

Study guide - Flashcard