CHEM 122 Midterm Review

Week 1 - CHEM 121 Review

100

What is the density of a substance with a mass of 46.345g and displaces 6.5mL of water in a graduated cylinder?

7.13g/cm³

200

Calculate the molar mass of H₂SO_4.

98.07

300

What is the element and charge on an ion that has 24 protons, a mass number of 52, and 20 electrons?

Cr⁴⁺

400

What is the electron configuration for aluminium?

1s²2s²2p⁶3s²3p¹     or     [Ne]3s²3p¹  

500

List the names and formula of six polyatomic ions.

Ammonium                NH₄⁺

Hydroxide or alcohol   OH^-

Nitrate                       NO₃^-

Carbonate                  CO₃^2-

Sulfate                       SO₄^2-

Phosphate                   PO₄^3-

Week 2 - Lewis Structures and Molecular Geometry

100

How many valence electrons does sulfur have?

6

200

What is the bonding capacity of boron?

3

300

What is the steric number of ammonia, NH₃?

SN = 4

400

What is the electron-pair geometry and molecular geometry of SO₂?

Electron-pair geometry: Trigonal planar

Molecular geometry: Bent (angular)

500

What is the molecular shape and the hybridization of the nitrogen atom in NH₃?

Trigonal pyramidal and sp³

Week 3 - Intermolecular Forces

100

Which molecules have London Dispersion Forces?

A. CO₂

B. H₂O

C. HF

D. MgS

All molecules exhibit LDF.

200

Hydrogen bonds require what?

Hydrogen must be bonded to N, O, or F.

300

Using the phase diagram below, give any temperature and pressure where CO₂ would be in the liquid phase.

Temp between -56.7C and 31C

Pressure between 5.1atm and 72.9atm

400

Which of the following molecules are polar?

A. CS₂

B. H₂O

C. HF

D. O₂

H₂O, HF

500

Week 4 - Chemical Reactions and Stoichiometry

100

What are the coefficients needed to balance the equation?

Al + O₂ --->  Al₂O₃

4, 3, 2

200

Where do you get the information for:

A. Molar Mass

B. Mole Ratio

C. Calculating the number of molecules, atoms, or particles

A. Periodic table

B. Balanced chemical equation (RXN)

C. Avagadro's number, 6.022x10²³

300

If you start with 37.0g of water, how many moles of sodium will it react with?

Na + H₂O ---> NaOH + H₂

2.1mol Na

400

Some cars use butane (C₄H₁₀) as fuel:

2C₄H₁₀ + 13O₂ ---> 8 CO₂ + 10H₂O

How many grams of H₂O are produced when 5.38g of O₂ is reacted?

2.33g H₂O

500

Na₂SiO₃
(s)
 + 
8
HF(aq) -
--> H₂SiF₆(aq)
 + 
2
NaF(aq)
 +
 3
H₂O
(l) 

How 
many 
moles 
of 
HF 
are 
needed 
to 
react
 with
 0.300
mol 
of
 Na₂SiO₃? 

2.4mol HF

Week 5 - Molecular Formula, Limiting Reactant, and Percent Yield

100

What is the molecular formula for a CH₂O with a molecular mass of 90g/mol?

C₃H₆O₃

200

What is the empirical formula of glucose, which contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen.

CH₂O

300

What is percent composition of a lab sample containing 24.02g carbon and 64.00g oxygen?

27.29% C

72.71% O

400

For the reaction below, 1.56g of BaCl₂ is used and is the limiting reagent.  In the lab, there was 1.82g of AgCl produced.  What is the percent yield for this reaction?

BaCl₂ + AgNO₃ ---> AgCl + Ba(NO₃)₂

84.6% yield AgCl

500

Given the chemical equation:

H₂ + N₂ ---> NH₃

What is the limiting reagent give 5.0g of each of the reactants, and what is the theoretical yield?

N₂ is the limiting reagent, and 12.1g is the theoretical yield.