Q: How many molecules are present in 1.75 moles of carbon dioxide ($$CO_2$$)? Use Avogadro's number ($$6.02 \times 10$$^{23}$$ molecules/mole).

$$1.05 \times 10$$^{24}$$ molecules$

Q: Which conversion factor would you use to convert grams of $$NaCl to $$moles of $$NaCl$$?

$$\frac{1 \text{ mole NaCl}}{58.44 \text{ g NaCl}}$$

Question 1

How many molecules are present in 1.75 moles of carbon dioxide ($$CO_2$$)? Use Avogadro's number ($$6.02 	imes 10$$^{23}$$ molecules/mole).

Accepted Answer

$$1.05 	imes 10$$^{24}$$ molecules$

Question 2

A patient takes 1.50 moles of aspirin ($$C_9H_8O_4). $$How many moles of carbon atoms are present?

Accepted Answer

$$13.5$$ moles$

Question 3

Calculate the molar mass of lithium carbonate ($$Li_2CO_3) $$using the following atomic masses: $$Li = 6.941 g/$$mol, $$C = 12.01 g/$$mol, $$O = 16.00 g/$$mol.

Accepted Answer

$$73.89 g/$$mol$

Question 4

How many grams of silver ($$Ag) $$are needed to make a piece of jewelry requiring $$0.750$$ moles of silver? (Molar mass of $$Ag = 107.9 g/$$mol)

Accepted Answer

$$80.9 g$

Question 5

A salt shaker contains $$73.7 g of $$sodium chloride ($$NaCl). $$How many moles of $$NaCl$$ are present? ($$Na = 22.99 g/$$mol, $$Cl = 35.45 g/$$mol)

Accepted Answer

$$1.26$$ moles$

Question 6

In the balanced chemical equation $$2Fe(s) + 3S(s) \rightarrow Fe_2S_3(s)$$, how many moles of sulfur are needed to react with $$1.42$$ moles of iron?

Accepted Answer

$$2.13$$ moles$

Question 7

Which of the following is the correct balanced equation for the combustion of methane ($$CH_4) in $$oxygen ($$O_2$$)?

Accepted Answer

$$CH_4(g) + 2O_2(g$$) \rightarrow $$CO_2(g) + 2H_2O(g$$)$$

Question 8

Balance the following equation involving polyatomic ions: $$Na_3PO_4(aq) + $$MgCl_2$$(aq) \rightarrow Mg_3$(PO_4$)_2(s) + NaCl(aq). $$What are the correct coefficients?

Accepted Answer

$$2, 3, 1, 6$$

Question 9

Which type of reaction is represented by $$KCIO_3(s$$) \rightarrow 2KCl(s) + 3O_2(g)$$?

Accepted Answer

Decomposition

Question 10

In the reaction $$Al(s) + 3Zn$$^{2+}$$(aq) \rightarrow 2Al$$^{3+}$$(aq) + 3Zn(s)$$, which reactant is oxidized and which is reduced?

Accepted Answer

$$Al is $$oxidized, $$Zn^{2+} is $$reduced

Question 11

How many grams of $$CO_2$$ are produced when $$54.6 g of $$acetylene ($$C_2H_2) is $$burned in oxygen? (Molar mass $$C_2H_2 = 26.04 g/$$mol, $$CO_2 = 44.01$ g/mol, reaction: 2C_2H_2 + 5O_2$$ \rightarrow 4CO_2 + 2H_2O$$)

Accepted Answer

$$184 g$

Question 12

A reaction of $$1$$ mole of solid carbon with oxygen gas produces carbon dioxide and $$393 kJ of $$energy. Is this reaction exothermic or endothermic?

Accepted Answer

Exothermic

Question 13

Which of the following is a combustion reaction?

Accepted Answer

$$C_2H_2(g) + O_2$(g) \rightarrow CO_2$(g) + H_2O(g)$$

Question 14

Which of the following best describes the role of coefficients in a balanced chemical equation?

Accepted Answer

They indicate the relative number of moles of each substance involved in the reaction.

Question 15

If the number of $$O_2$$ molecules is increased in the reaction $$C(s) + O_2$(g) \rightarrow CO_2$(g) + 393 kJ$$, what will happen to the rate of the reaction?

Accepted Answer

The rate will increase.

Question 16

Which conversion factor would you use to convert grams of $$NaCl to $$moles of $$NaCl$$?

Accepted Answer

$$\frac{1 	ext{ mole NaCl}}{58.44 	ext{ g NaCl}}$$

Question 17

Which of the following is a single replacement reaction?

Accepted Answer

$$Fe_2O_3(s) + 3C(s) \rightarrow 3CO_2(g) + 4Fe(s)$$

Chemical Quantities and Reactions: Structured Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard