Question 1

Which of the following elements will generally form only one covalent bond due to having only one valence electron?

Accepted Answer

Hydrogen

Question 2

How many lone pairs of electrons are needed to complete the Lewis structure of aspartic acid, given that each oxygen atom not involved in a double bond must have two lone pairs and each nitrogen atom must have one lone pair?

Accepted Answer

Nine

Question 3

Which of the following molecules will NOT contain a multiple bond in its Lewis structure?

Accepted Answer

NCl$$_3$$

Question 4

What is the molecular formula for dinitrogen pentoxide?

Accepted Answer

N$$_2O$_5$$

Question 5

What is the molecular shape around the phosphorus atom in PH$$_3$$?

Accepted Answer

Trigonal pyramidal

Question 6

Which atom has the lowest electronegativity among the following?

Accepted Answer

Rb

Question 7

How many polar bonds does acetaldehyde (CH$$_3$$CHO) contain?

Accepted Answer

Three

Question 8

Which of the following bonds has its polarity INCORRECTLY labeled?

Accepted Answer

$$\delta^+\ \mathrm{O}-\mathrm{C}\ \delta^-$$

Question 9

What is the bond angle around the sulfur atom in SO$$_3$$?

Accepted Answer

$$120^\circ$$

Question 10

Which molecule or ion has only two resonance structures?

Accepted Answer

$$\mathrm{HCO}_3^-$$

Question 11

How many valence electrons are present in the OBr$$^-$$ ion?

Accepted Answer

14

Question 12

Which compound is named incorrectly according to IUPAC nomenclature?

Accepted Answer

P$$_2O$_4$$ – diphosphorus tetroxide

Question 13

In the balanced equation for the rusting of iron: $$4\ \mathrm{Fe}(s) + 3\ \mathrm{O}_2(g) \rightarrow \_\_\_\ \mathrm{Fe}_2\mathrm{O}_3(s)$$, what coefficient should be placed in front of Fe$$_2O$_3$$?

Accepted Answer

2

Question 14

How many carbon atoms are present in 3.85 mol of carbon?

Accepted Answer

2.32 	imes $$10^{24}$$

Question 15

What is the formula weight of KCl?

Accepted Answer

74.55\ \mathrm{amu}

Question 16

What is the mass of 3.81 mol of PH$$_3$$? (Molar mass of PH$$_3 = 34.0 g/$$mol)

Accepted Answer

130\ \mathrm{g}

Question 17

Consider the reaction: $$2\ \mathrm{H}_2(g) + \mathrm{O}_2(g) \rightarrow 2\ \mathrm{H}_2\mathrm{O}(g). If 8 $$molecules of H$$_2$$ react with 4 molecules of O$$_2$$, how many molecules of water are produced?

Accepted Answer

8

Question 18

How many molecules are in 2.40 moles of sucrose (C$$_{12}H$_{22}O$_{11}$$)?

Accepted Answer

1.44 	imes $$10^{24}$$

Question 19

Given the reaction: $$\mathrm{N}_2(g) + 2\ \mathrm{O}_2(g) \rightarrow 2\ \mathrm{NO}_2(g)$$, if you start with 5 molecules of N$$_2$$ and 12 molecules of O$$_2$$, and 5 molecules of N$$_2$$ and 10 molecules of O$$_2$$ are used, how many molecules of NO$$_2$$ are formed?

Accepted Answer

10 molecules

Question 20

Consider the precipitation reaction: $$\mathrm{BaCl}_2 + 2\ \mathrm{AgNO}_3 \rightarrow 2\ \mathrm{AgCl} + \mathrm{Ba(NO}_3)_2. $$How many grams of AgCl are generated when 85 g of BaCl$$_2 ($$molar mass = 208.23 g/mol) reacts completely? (Molar mass of AgCl = 143.32 g/mol)

Accepted Answer

140 g

Chem 140A Exam 2 Study Guidance

Guida di studio - Domande di pratica

Study guide - Flashcard