Q: How many oxygen atoms are present in $$1.04$$ mol of $$\mathrm{$$MgSO_4$$}$$?

$$2.51 \times 10$$^{24}$$ atoms

Q: A sample contains $$0.140 g of$$ $$\mathrm{HCl}. $$How many molecules of $$\mathrm{HCl}$$ are present? (Molar mass of $$\mathrm{HCl} = 36.5 g/$$mol)

$$2.31 \times 10$$^{21}$$ molecules

Question 1

How many oxygen atoms are present in $$1.04$$ mol of $$\mathrm{$$MgSO_4$$}$$?

Accepted Answer

$$2.51 	imes 10$$^{24}$$ atoms

Question 2

A sample contains $$0.140 g of$$ $$\mathrm{HCl}. $$How many molecules of $$\mathrm{HCl}$$ are present? (Molar mass of $$\mathrm{HCl} = 36.5 g/$$mol)

Accepted Answer

$$2.31 	imes 10$$^{21}$$ molecules

Question 3

What is the mass of $$1.36 	imes 10$$^{22}$$ molecules of $$\mathrm{HCl}$$? (Molar mass of $$\mathrm{HCl} = 36.5$$ g/mol, N_A = 6.022$$ 	imes $$10^{23})$$

Accepted Answer

$$0.824 g$$

Question 4

Which of the following is the correct molar mass for calcium sulfate ($$\mathrm{$$CaSO_4$$}$$)?

Accepted Answer

$$136.14 g/$$mol

Question 5

What is the percent by mass of carbon in carbon dioxide ($$\mathrm{CO_2$}$$)? (Atomic masses: C = 12.01, O = 16.00)

Accepted Answer

$$27.28\%$$

Question 6

A compound has the empirical formula $$\mathrm{CH}$$ and a molar mass of $$26.04 g/$$mol. What is its molecular formula?

Accepted Answer

$$\mathrm{C_2H_2}$$

Question 7

Which of the following ions is an anion?

Accepted Answer

nitrate ion

Question 8

Which region of the electromagnetic spectrum has the longest wavelength?

Accepted Answer

microwave

Question 9

How many orbitals are contained in the $$3s$$ sublevel?

Accepted Answer

1

Question 10

What is the maximum number of electrons that can occupy the second principal energy level ($$n=2$$)?

Accepted Answer

8

Question 11

Which element has the electron configuration $$1s^2$$\ $$2s^2$$\ $$2p^3$$?

Accepted Answer

nitrogen

Question 12

As you move from top to bottom within a group on the periodic table, atomic radius generally:

Accepted Answer

increases

Question 13

Which type of chemical bond involves the sharing of electrons?

Accepted Answer

covalent (molecular)

Question 14

The ionization energy of chlorine ($$\mathrm{Cl}) is __________ $$compared to fluorine ($$\mathrm{F}).$$

Accepted Answer

lower

Question 15

A substance is found to consist of $$1.900 g of $$silver, $$0.250 g of $$nitrogen, and $$0.850 g of $$oxygen. What is the percent by mass of oxygen in the compound?

Accepted Answer

$$28.3\%$$

Question 16

What is the empirical formula of a compound containing $$3.09\%$$ hydrogen, $$31.60\%$$ phosphorus, and $$65.31\%$$ oxygen by mass?

Accepted Answer

$$\mathrm{H_3PO_4}$$

Question 17

Which of the following is the correct chemical formula for tin(IV) hydroxide?

Accepted Answer

$$\mathrm{Sn(OH)_4}$$

Question 18

Which of the following best describes the trend in atomic radius as you move left to right across a period in the periodic table?

Accepted Answer

decreases

Question 19

According to the Pauli exclusion principle, any orbital can hold at most how many electrons?

Accepted Answer

2

Question 20

Which of the following ions is a cation?

Accepted Answer

potassium ion

Intro to Chemistry Exam 2: Step-by-Step Study Guidance (Chapters 5–7)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드