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

A unit representing 6.022 \times $$10^{23}$$ particles of a substance.

Q: How many molecules are in 2.5 moles of water ($$\mathrm{H_2O}$$)?

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

Question 1

Which of the following best describes a mole in chemistry?

Accepted Answer

A unit representing 6.022 	imes $$10^{23}$$ particles of a substance.

Question 2

How many molecules are in 2.5 moles of water ($$\mathrm{H_2O}$$)?

Accepted Answer

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

Question 3

What is the molar mass of sodium chloride ($$\mathrm{NaCl}$$)?

Accepted Answer

$$58.44\ \mathrm{g/mol}$$

Question 4

A patient receives 18 grams of glucose ($$\mathrm{C_6H_{12}O_6$}). $$How many moles of glucose did they receive? (Molar mass of glucose = $$180\ \mathrm{g/mol})$$

Accepted Answer

$$0.10$$ moles

Question 5

In the reaction $$2\mathrm{H_2$} + \mathrm{O_2$} \rightarrow 2\mathrm{H_2O}$$, what do the coefficients represent?

Accepted Answer

The ratio of moles of each substance involved.

Question 6

Given the balanced equation $$\mathrm{N_2$} + 3\mathrm{H_2$} \rightarrow 2\mathrm{NH_3$}$$, how many moles of $$\mathrm{NH_3$}$$ are produced from 6 moles of $$\mathrm{H_2$}$$?

Accepted Answer

4 moles

Question 7

A reaction requires 5.0 grams of $$\mathrm{NaOH} ($$molar mass $$= 40\ \mathrm{g/mol}). $$How many moles of $$\mathrm{NaOH} is $$this?

Accepted Answer

$$0.125$$ moles

Question 8

In a reaction, 10 grams of $$\mathrm{$$CaCO_3$$} ($$molar mass $$= 100\ \mathrm{g/mol}) $$reacts with excess $$\mathrm{HCl}. $$What mass of $$\mathrm{CO_2$} ($$molar mass $$= 44\ \mathrm{g/mol}) is $$produced? ($$\mathrm{$$CaCO_3$$} + 2\mathrm{HCl} \rightarrow \mathrm{$$CaCl_2$$} + \mathrm{CO_2$} + \mathrm{H_2O})$$

Accepted Answer

$$4.4$$ grams

Question 9

Which reactant is the limiting reactant when 3 moles of $$\mathrm{Al}$$ react with 4 moles of $$\mathrm{O_2$} in $$the reaction $$4\mathrm{Al} + 3\mathrm{O_2$} \rightarrow 2\mathrm{Al_2O_3}$$?

Accepted Answer

$$\mathrm{Al}$$

Question 10

A student performs a reaction and obtains 8.0 grams of product. The theoretical yield is 10.0 grams. What is the percent yield?

Accepted Answer

$$80\%$$

Question 11

Which of the following is an example of an endothermic process?

Accepted Answer

Melting ice

Question 12

What is the specific heat of water in units of $$\mathrm{J/(g\cdot ^\circ C)}$$?

Accepted Answer

$$4.18\ \mathrm{J/(g\cdot ^\circ C)}$$

Question 13

A food item contains 10 grams of fat, 20 grams of carbohydrate, and 5 grams of protein. What is its total energy content in Calories? (Fat: 9 Cal/g, Carb: 4 Cal/g, Protein: 4 Cal/g)

Accepted Answer

150 Calories

Question 14

Convert $$25\ ^\circ \mathrm{C} to $$Kelvin.

Accepted Answer

$$298\ \mathrm{K}$$

Question 15

Which intermolecular force is strongest?

Accepted Answer

Hydrogen bonding

Question 16

Which substance would have the highest boiling point?

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 17

According to the kinetic molecular theory, which statement is true about gases?

Accepted Answer

Gas particles move rapidly and randomly.

Question 18

If the volume of a balloon is decreased at constant temperature, what happens to the pressure inside the balloon according to Boyle’s Law?

Accepted Answer

Pressure increases

Question 19

A 2.0 L sample of gas at $$1.0\ \mathrm{atm}$$ and $$300\ \mathrm{K} is $$compressed to $$1.0\ \mathrm{L} at $$constant temperature. What is the new pressure?

Accepted Answer

$$2.0\ \mathrm{atm}$$

Question 20

What is the volume occupied by 1 mole of an ideal gas at standard temperature and pressure (STP)?

Accepted Answer

$$22.4\ \mathrm{L}$$

Study Guide: CHEM 14 Chapters 6–8 (Quantities, Energy, States of Matter, and Gases)

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