$$1.51 \times 10$$^{24}$$ atoms

Question 1

Which of the following statements correctly describes a covalent bond?

Accepted Answer

A covalent bond is formed when two atoms share one or more pairs of electrons.

Question 2

How many covalent bonds does a nitrogen atom typically form in a molecule?

Accepted Answer

Three

Question 3

What is the correct Lewis dot structure for a fluorine atom?

Accepted Answer

$$\mathrm{F}\cdot\cdot\cdot\cdot\cdot\cdot\cdot$$

Question 4

Which of the following compounds is a binary covalent compound?

Accepted Answer

CO$$_2$$

Question 5

What is the name of the compound with the formula $$\mathrm{N_2O_4}$$?

Accepted Answer

Dinitrogen tetroxide

Question 6

How many moles are present in 36.03 grams of water ($$\mathrm{H_2O}$$)? (Molar mass of $$\mathrm{H_2O} = 18.02 g/$$mol)

Accepted Answer

$$2.00$$ moles

Question 7

Which of the following is the correct formula for carbon monoxide?

Accepted Answer

CO

Question 8

How many atoms are present in 2.5 moles of sodium? (Avogadro’s number $$= 6.02 	imes 10$$^{23}$$ atoms/mol)

Accepted Answer

$$1.51 	imes 10$$^{24}$$ atoms

Question 9

What is the molar mass of propane ($$\mathrm{C_3H_8}$$)? (Atomic masses: C = 12.01 g/mol, H = 1.01 g/mol)

Accepted Answer

$$44.11 g/$$mol

Question 10

Which of the following best describes the difference between ionic and covalent compounds?

Accepted Answer

Ionic compounds are formed between metals and nonmetals, while covalent compounds are formed between nonmetals.

Question 11

What is the mass of $$0.25$$ mol of propane ($$\mathrm{C_3H_8}$$)? (Molar mass $$= 44.11 g/$$mol)

Accepted Answer

$$11.03 g$$

Question 12

Which of the following is the correct name for $$\mathrm{$$PCl_5$$}$$?

Accepted Answer

Phosphorus pentachloride

Question 13

How many moles of fluorine atoms are present in $$5.5$$ moles of $$\mathrm{$$CaF_2$$}$$?

Accepted Answer

$$11.0$$ moles

Question 14

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

Accepted Answer

$$\mathrm{N_2O_4}$$

Question 15

What is the total number of valence electrons in a molecule of water ($$\mathrm{H_2O}$$)?

Accepted Answer

8

Question 16

Which of the following molecules contains a triple bond?

Accepted Answer

$$\mathrm{N_2$}$$

Question 17

What is the correct name for $$\mathrm{Cl_2O_7}$$?

Accepted Answer

Dichlorine heptoxide

Question 18

Which of the following is the correct formula for silicon tetrachloride?

Accepted Answer

$$\mathrm{$$SiCl_4$$}$$

Question 19

If you have $$3.01 	imes 10$$^{23}$$ atoms of carbon, how many moles of carbon do you have?

Accepted Answer

$$0.5$$ moles

Question 20

Which of the following is the correct name for $$\mathrm{NO_2$}$$?

Accepted Answer

Nitrogen dioxide

Compounds—How Elements Combine: Covalent Bond Formation and The Mole

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