Q: How many molecules are present in $$0.75$$ mole of $$CO_2$$?

$$1.20 \times 10$$^{24}$$ molecules

Q: How many atoms of oxygen are in $$0.200$$ mole of aspirin ($$C_9H_8O_4$$)?

$$4.82 \times 10$$^{23}$$ atoms

Question 1

Which statement best describes Avogadro's number?

Accepted Answer

It is the number of particles (atoms, molecules, or ions) in one mole of a substance.

Question 2

How many molecules are present in $$0.75$$ mole of $$CO_2$$?

Accepted Answer

$$1.20 	imes 10$$^{24}$$ molecules

Question 3

A sample contains $$3.01 	imes 10$$^{23}$$ atoms of sodium (Na$). How many moles of sodium are present?

Accepted Answer

$$0.50$$ moles

Question 4

What is the molar mass of $$C_2H_6O ($$ethanol)? (Atomic masses: C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol)

Accepted Answer

$$46.07 g/$$mol

Question 5

How many atoms of oxygen are in $$0.200$$ mole of aspirin ($$C_9H_8O_4$$)?

Accepted Answer

$$4.82 	imes 10$$^{23}$$ atoms

Question 6

Which of the following is a balanced chemical equation?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 7

Which type of reaction is represented by the following equation? $$2KClO_3(s) \rightarrow 2KCl(s) + 3O_2(g)$$

Accepted Answer

Decomposition reaction

Question 8

In the reaction $$Zn(s) + 2HCl(aq) \rightarrow $$ZnCl_2$$(aq) + H_2$(g)$$, which element is oxidized?

Accepted Answer

Zinc

Question 9

A combustion reaction always involves which of the following?

Accepted Answer

A carbon-containing compound reacting with oxygen to produce $$CO_2$$ and $$H_2O$$

Question 10

What is the mass of $$0.250$$ mole of $$H_2O$$? (Molar mass of $$H_2O is$$ $$18.02 g/$$mol)

Accepted Answer

$$4.51 g$$

Question 11

Which factor will increase the rate of a chemical reaction?

Accepted Answer

Adding a catalyst

Question 12

In the reaction $$2Al(s) + 3Cl_2(g) \rightarrow 2AlCl_3(s)$$, what is the mole ratio of $$Al to$$ $$Cl_2$$?

Accepted Answer

$$2:3$$

Question 13

If $$4.0$$ moles of $$Fe$$ react with excess $$O_2$$ according to $$4Fe(s) + 3O_2(g) \rightarrow 2Fe_2O_3(s)$$, how many moles of $$Fe_2O_3$$ are produced?

Accepted Answer

$$2.0$$ moles

Question 14

Which of the following best describes an endothermic reaction?

Accepted Answer

Heat is absorbed and the energy of the products is greater than the reactants.

Question 15

A patient is exposed to carbon monoxide ($$CO) $$and $$30\% of $$their hemoglobin is bound to $$CO. $$What symptoms are most likely?

Accepted Answer

Dizziness, mental confusion, severe headache, and nausea

Question 16

Which of the following is NOT a requirement for a chemical reaction to occur?

Accepted Answer

Products must be in the gaseous state

Question 17

What is the mass of $$2.50$$ moles of $$CH_4$$? (Molar mass of $$CH_4 is$$ $$16.05 g/$$mol)

Accepted Answer

$$40.13 g$$

Question 18

Which of the following reactions is a double replacement reaction?

Accepted Answer

$$AgNO_3(aq) + $$NaCl(aq) \rightarrow AgCl(s) + $$NaNO_3(aq$$)$$

Question 19

Which statement about catalysts is correct?

Accepted Answer

A catalyst increases the rate of reaction and lowers the energy of activation.

Chemical Quantities and Reactions: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard