Q: How many molecules of water are present in $$1.058 g of$$ $$\mathrm{H_2O}$$? (Molar mass $$= 18.015 g/$$mol, Avogadro's number $$= 6.022 \times 10$$^{23}$$)

$$3.537 \times 10$$^{22}$$ molecules

Question 1

Which of the following best describes the concept illustrated in the first image (target with clustered marks)?

Accepted Answer

Precise but not accurate

Question 2

What is the correct molecular formula for the compound shown in the second image (yellow central atom with three red atoms)?

Accepted Answer

$$\mathrm{SO_3$}$$

Question 3

How many moles of $$\mathrm{O_2$}$$ will be formed from 1.65 moles of $$\mathrm{$$KClO_3$$}$$ according to the reaction $$2\mathrm{$$KClO_3$$} \rightarrow 2\mathrm{KCl} + 3\mathrm{O_2$}$$?

Accepted Answer

$$2.48$$ mol $$\mathrm{O_2$}$$

Question 4

How many molecules of water are present in $$1.058 g of$$ $$\mathrm{H_2O}$$? (Molar mass $$= 18.015 g/$$mol, Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$3.537 	imes 10$$^{22}$$ molecules

Question 5

Which sample contains more molecules: $$10.0 g of$$ $$\mathrm{O_2$} or$$ $$50.0 g of$$ $$\mathrm{I_2$}$$? (Molar masses: $$\mathrm{O_2$} = 31.998 g/$$mol, $$\mathrm{I_2$} = 253.8 g/$$mol)

Accepted Answer

$$10.0 g of$$ $$\mathrm{O_2$}$$

Question 6

What is the molar mass of $$\mathrm{$$PbSO_4$$}$$?

Accepted Answer

$$303.3 g/$$mol

Question 7

How many grams of $$\mathrm{Fe_2O_3}$$ are produced when $$42.7$$ grams of $$\mathrm{Fe}$$ are reacted according to $$4\mathrm{Fe} + 3\mathrm{O_2$} \rightarrow 2\mathrm{Fe_2O_3}$$?

Accepted Answer

$$61.0 g$$

Question 8

How many grams of $$\mathrm{CO_2$}$$ are produced from the combustion of $$100.0$$ grams of butane ($$\mathrm{C_4H_{10}}$$)?

Accepted Answer

$$303 g$$

Question 9

In the reaction $$2\mathrm{Al}(s) + \mathrm{Fe_2O_3}(s) \rightarrow 2\mathrm{Fe}(l) + \mathrm{Al_2O_3}(s)$$, if you start with $$5.4$$ moles of aluminum and $$15$$ moles of $$\mathrm{Fe_2O_3}$$, what is the limiting reactant and how many moles of iron can be formed?

Accepted Answer

Aluminum is the limiting reactant; $$5.4$$ moles of iron can be formed

Question 10

Which of the following is a diatomic element?

Accepted Answer

Nitrogen ($$\mathrm{N_2$})$$

Question 11

What is the empirical formula of glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 12

Which group in the periodic table is known as the Chalcogens?

Accepted Answer

Group 6 (or 16)

Question 13

Which of the following is a chemical change?

Accepted Answer

Burning gasoline

Question 14

What is the chemical formula for acetic acid?

Accepted Answer

$$\mathrm{CH_3COOH}$$

Question 15

How many significant figures are in the number $$1.050 	imes 10^9$?

Accepted Answer

4

Question 16

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements

Question 17

What is the formula for Iron(III) Chlorate?

Accepted Answer

$$\mathrm{Fe($$ClO_3$$)_3}$$

Question 18

How many neutrons are in one atom of $$^{79}\mathrm{Br}$$?

Accepted Answer

44

Question 19

Which group of elements is known to be inert?

Accepted Answer

Noble Gases

Question 20

What is the definition of an atom?

Accepted Answer

The smallest unit into which an element can be divided without losing its identity

General Chemistry Exam 1 Review: Matter, Atoms, Molecules, and Stoichiometry

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