Exam 4 Review

Chapters 1-2: Atomic Structure and Formula Calculations

100

What is the speed of light in nm/ms ?

Speed of light = 3.0x10⁸ m/s

3.0x10¹⁴ nm/ms

200

The formula for sodium dihydrogen phosphate is NaH₂PO₄

What is the formula of strontium dihydrogen phosphate?

Sr(H₂PO₄)₂

300

What is the percent of oxygen in phosphoric acid?

65.3%

400

Lithium has two naturally occuring isotopes, 6Li and 7Li, with masses of 6.015 amu and 7.016 amu. What is the relative abundance of each isotope?

6Li = 7.49%

7Li = 92.51 %

500

For each compound, classify as ionic, covalent, or an acid. Name the compound

a. CCl₄

b. H₂PO₄

c. K₃P

d. HgBr₂

e. H₂S

a. covalent, carbon tetrachloride

b. acid, phosphoric acid

c. ionic, potassium phosphide

d. mercury (II) bromide

e. (binary) acid, hydrosulfuric acid

Chapters 3-4: Stoichiometry and Solutions

100

What is the molarity of a solution prepared by dissolving 12.0 g NaCl in 300.0 mL water?

0.683 M

200

Which molecular equation would give this net ionic equation: H⁺(aq) + OH^-(aq) --> H₂O(l)

a. H₂SO₄(aq) + 2NH₃(aq) --> (NH₄)₂SO₄(aq)

b. HCN(aq) + KOH --> H₂O(l) + KCN(aq)

c. 2HClO₄(aq) + Ba(OH)₂(aq) --> 2H₂O(l) + Ba(ClO₄)₂(aq)

c. 2HClO₄(aq) + Ba(OH)₂(aq) --> 2H₂O(l) + Ba(ClO₄)₂(aq)

300

A 2.32 g sample of Na₂SO₄*nH₂O yields 1.42 g Na₂SO₄ upon heating.

Na₂SO₄*nH₂O --> Na₂SO₄ + nH₂O

What is the value of n?

n=5

400

How many grams of NaOH are required to neutralize 50.0 mL of 0.100 M H₂SO₄?

0.4 g NaOH

H₂SO₄ + 2NaOH --> Na₂SO₄ + 2H₂O

500

Adipic acid, C₆H₁₀O₄ (MM=146.15), is prepared by the partial oxidation of cyclohexane, C₆H₁₂ (MM = 84.16), according to the following balanced equation:

2C₆H₁₂(l) + 5O₂(g) --> 2C₆H₁₀O₄(s) + 2H₂O(l)

A sample of 25.0 g cyclohexane reacts with excess oxygen to give 33.5 g of adipic acid. What is the yield of the reaction?

77.2%

Chapters 5-6: Thermochemistry and Electronic Structure

100

How much heat (in J) is required to raise 75.0 g of water from 25 C to 55 C? (c=4.184 J/gC)

q = m*c*deltaT

9,414 J

200

What mass of Cl₂ is needed to release 45.2 kJ of energy as heat during this reaction?

C(s) + 2Cl₂(g) --> CCl₄(l)   deltaH = -135.4 kJ/mol

47.3 g

300

What is the frequency of light with a wavelength of 480 nm?

a. 1.60x10^-6 s^-1

b. 6.25x10⁵ s^-1

c. 6.25x10¹⁴ s^-1

d. 1.44x10²⁰ s^-1

c. 6.25x10¹⁴ s^-1

400

Which atom has the largest atomic radius?

a. K

b. Rb

c. I

d. Sn

Rb

500

Given the thermochemical data (on board) what is the deltaH_rxn for:

CO(g) + 1/2O₂(g) --> CO₂(g)

-284 kJ/mol

Chapters 7-8: Structure and Bonding

100

What is the molecular geometry of CO₃^2-?

a. bent

b. T-shaped

c. trigonal bipyramidal

d. trigonal planar

d. trigonal planar

200

How many lone pairs of electrons are on the central atom of ClF₃?

2 lone pairs

300

Which species contains three sigma bonds and one pi bond?

a. PF₃

b. NH₄⁺

c. CO₃^2-

c. CO₃^2-

400

Which of the molecules listed have an sp³ hybridized central atom?

I. PCl₃ II. COCl₂ III. SF₄

a. I only

b. I and III only

c. II and III only

d. I, II, and III

a. I only (PCl₃)

500

Which species has a trigonal planar geometry?

a. ClF₃

b. NCl₃

c. CO₃^-2

d. I₃^-1

c. CO₃^-2

Random

100

A central atom has two lone pairs and three single bonds. What is the molecular geometry?

T-shaped

200

SCl₂ has ____ bonds and overall the molecule is ____.

a) polar, polar

b) polar, nonpolar

c) nonpolar, polar

d) nonpolar, nonpolar

a) polar, polar

300

Which ionic compound has the largest magnitude lattice energy?

a) CaO

b) KBr

c) MgO

d) NaF

MgO

400

What is the oxidation number of Mo in MoO₄^2-?

+6

500

Balance:

NaBr + Cl₂ ---> NaCl + Br₂

2, 1, 2, 1