Q: Which of the following best describes a mole in chemistry?

A unit representing $$6.02 \times 10$$^{23}$$ particles (atoms, molecules, ions, or formula units)

Q: What is the molar mass of $$HCIO_3$$ given the atomic masses: $$H = 1.01 g/$$mol, $$Cl = 35.45 g/$$mol, $$O = 16.00 g/$$mol?

$$1.01 + 35.45 + (3 \times 16.00) = 84.46 g/$$mol

Q: How many molecules are present in 2 moles of water ($$H_2O$$)?

$$2 \times 6.02 \times 10$$^{23}$$ = 1.204 \times 10$$^{24}$$ molecules

Q: Which equation correctly represents the relationship between mass, moles, and molar mass?

$$\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}$$

Question 1

Which of the following best describes a mole in chemistry?

Accepted Answer

A unit representing $$6.02 	imes 10$$^{23}$$ particles (atoms, molecules, ions, or formula units)

Question 2

Sucrose has the formula $$C_{12}H$$_{22}$$O_{11}$. How many moles of hydrogen atoms are present in 1 mole of sucrose?

Accepted Answer

22 moles

Question 3

What is the molar mass of $$HCIO_3$$ given the atomic masses: $$H = 1.01 g/$$mol, $$Cl = 35.45 g/$$mol, $$O = 16.00 g/$$mol?

Accepted Answer

$$1.01 + 35.45 + (3 	imes 16.00) = 84.46 g/$$mol

Question 4

If you have 168.92 grams of $$HCIO_3$$, how many moles do you have? (Molar mass of $$HCIO_3 is$$ $$84.46 g/$$mol)

Accepted Answer

$$\frac{168.92}{84.46} = 2.00$$ moles

Question 5

Which type of chemical reaction is represented by $$AB + CD \rightarrow AD + BC$$?

Accepted Answer

Double replacement

Question 6

A reaction where a compound breaks down into two or more simpler substances is called:

Accepted Answer

Decomposition

Question 7

Which of the following reactions is an example of combustion?

Accepted Answer

$$C_xH_y + O_2$ \rightarrow CO_2$ + H_2O$$

Question 8

In the reaction $$2Al^{3+}$$ + $$3Sn^{2+}$$ \rightarrow 2Al + $$3Sn^{4+}$$, which element is oxidized?

Accepted Answer

Aluminum ($$Al)$$

Question 9

Which statement correctly describes oxidation in a redox reaction?

Accepted Answer

Oxidation is the loss of electrons

Question 10

A patient receives 18 grams of glucose ($$C_6H_{12}O_6$). What is the number of moles of glucose given? (Molar mass of glucose = 180$ g/mol)

Accepted Answer

$$\frac{18}{180} = 0.10$$ moles

Question 11

Which of the following best describes an exothermic reaction?

Accepted Answer

A reaction that releases heat to the surroundings

Question 12

If a chemical reaction has $$E_{product} \u003c E_{reactant}$$, what can be concluded about the reaction?

Accepted Answer

The reaction is exothermic

Question 13

How many molecules are present in 2 moles of water ($$H_2O$$)?

Accepted Answer

$$2 	imes 6.02 	imes 10$$^{23}$$ = 1.204 	imes 10$$^{24}$$ molecules

Question 14

Which equation correctly represents the relationship between mass, moles, and molar mass?

Accepted Answer

$$	ext{moles} = \frac{	ext{mass (g)}}{	ext{molar mass (g/mol)}}$$

Question 15

A reaction requires 3 moles of $$O_2 to $$produce 6 moles of $$CO_2. $$What is the mole ratio of $$O_2 to$$ $$CO_2$$?

Accepted Answer

$$1:2$$

Question 16

Which of the following is NOT a type of chemical reaction described in the study materials?

Accepted Answer

Polymerization

Question 17

In a double replacement reaction, what is exchanged between the reactants?

Accepted Answer

Ions

Question 18

Which of the following best describes reduction in a redox reaction?

Accepted Answer

Reduction is the gain of electrons

Question 19

A student balances the equation $$C_2H_6 + O_2$ \rightarrow CO_2$ + H_2O$$ and finds the coefficients to be $$2, 7, 4, 6$$ respectively. What type of reaction is this?

Accepted Answer

Combustion

Question 20

A hospital uses $$84.46$$ grams of $$HCIO_3 in a $$solution. How many molecules are present in this sample? (Molar mass $$= 84.46 g/$$mol, $$1$$ mole $$= 6.02 	imes 10$$^{23}$$ molecules)

Accepted Answer

$$6.02 	imes 10$$^{23}$$ molecules

Chemical Quantities and Chemical Reactions: Study Notes

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