Study Guide for Quiz 2
For each lab, review all pre-lab questions, reports and post-lab questions. Look at corrections made on your lab report
during grading. Work the sample questions below. Remember that all possible types of questions are not represented.
These study questions are a sampling of the possible questions.
VSEPR Modeling : Be able to fill in a table like the following:
NO3-
Molecular Formula
Number of Valence eLewis Dot Structure
Molecular Type (i.e.
AB2E2)
Electron Pair Geometry
(name and sketch)
Molecular Geometry
(name and sketch)
Gas Laws
1. Review the details for performing the Boyle’s Law and Charles’ Law experiments and be able to answer questions
about the experimental procedure for them. For example, how was pressure on the gas increased in the Boyle’s Law
experiment?
2. Know the equations for Charles’ and Boyle’s law and be able to use them by working a problem.
3. Given data from a Boyle’s law experiment like you performed in lab:
a) Be able to complete a table like the one below.
Trial
Mass Added
Volume (mL) Pressure (total mass, kg)
(kg)
0.5
25.9
6.1
1
2
1.5
23.3
PxV
7.1
b) Calculate the theoretical volume for Trial 2 using Boyle’s Law formula and the data from Trial 1 & 2.
(See Boyle’s Law post- lab question 2 on page 9.)
c) Calculate the % error for the experimental V2 as you did in Boyle’s Law post lab question 3 (page 9).
4. Be able to calculate a theoretical V2 for a Charles Law experiment given appropriate experimental data. Then be
able to calculate a % error for the experimental V2. (See page 8 of your lab report.)
5. Be able to answer questions from the Charles’ Law post lab.
Example: What happened to the speed of the molecules when the air in the flask was heated?
Chemistry of Copper Lab
In general: Be able to identify the type of reaction, predict products, write correct formulas, and balance equations.
Know the colors of all the copper containing products.
Review the experiment and your results. Make sure you understand each step that you performed. For example, why
was reaction 1 performed in the hood?
1. Classify the type of reaction and balance the equation: Cu + O2 → CuO
2. Classify the reaction, predict the products, balance the equation and write the net ionic equation for
Cu (s) + AgNO3 (aq) →
3. Calculate the percent yield if you started with 1.56 g of copper wire and recovered 0.88 g of copper.
4. What was the color of CuO?
Representing Organic Structures
Be able to write expanded structures from line structures and vice versa. (p. 11 in lab)
1. Are the following compounds isomers, the same compound or neither? (Two compounds are isomers if they have
the same molecular formula, but different structure.)
H
C
H
H
H
C
H
H
C
C
H
H
H
H
C
C
H
C
H
H
H
H
H
H
C
H
H
H
2. Draw a flat picture of a six carbon alkane with the longest possible chain of carbon atoms. Indicate the name and
formula. Then rearrange the carbon chain to form an isomer.
isomer
longest chain
# of C in
main chain
2
3
4
5
6
7
name:
formula: ________________
3. Draw a perspective line drawing for cis-1,2-dichlorocyclopentane (question 1, postlab).
4. Draw flat structures for two isomers of dibromopropane (C3H6Br2) and name them.
5. What is necessary for a carbon to be chiral?
6. Draw a perspective view of an alkene with the formula C2H2Cl2
Some Answers
VSEPR
Molecular Formula
Number of Valence e-
NO324 valence electron
_
Lewis Dot Structure
O
O
N
O
name
ethane
propane
butane
pentane
hexane
heptane
Molecular Type (i.e. AB2E2)
Electron Pair Geometry (name
and sketch)
Molecular Geometry
(name and sketch)
AB3
trigonal planar
trigonal planar
Gas Laws
1. The pressure on the gas was increased by adding weights on top of the syringe.
2. Charles’ Law, V1 / T1 = V2 / T2
Boyle’s law, P1V1 = P2V2
3. Given data from a Boyle’s law experiment like you performed in lab:
a) Be able to complete a table like the one below.
Trial
Mass Added
Volume (mL) Pressure (total mass, kg)
(kg)
0.5
25.9
6.1
1
2
PxV
(157.99) 160 kg . mL
1.5
23.3
7.1
(165.43) 170 kg . mL
b) Calculate the theoretical volume for Trial 2 using Boyle’s Law formula and the data from Trial 1 & 2.
First list the values for each pressure and volume: P1 = 6.1 kg, V1 = 25.9 mL, and P2 = 7.1 kg
Boyle’s Law: P1V1 = P2V2
V2
=
P1 V1
P2
=
6.125.9
7.1
= (22.25211) 22 mL
5. The speed of the molecules increased when the air in the flask was heated.
Chemistry of Copper Lab
1. Classify the type of reaction and balance the equation:
2 Cu + O2 → 2 CuO
Combination or synthesis
2. Classify the reaction, predict the products, balance the equation and write the net ionic equation for
Single replacement
Cu (s) + 2 AgNO3 (aq) → 2 Ag
+ Cu(NO3)2
(This reaction proceeds because copper is more active than silver.)
NIE
Cu (s) + 2 Ag+ (aq) → 2 Ag + Cu2+
3. Calculate the percent yield if you started with 1.56 g of copper wire and recovered 0.88 g of copper.
.
.
x 100% = 56.4% rounds to 56%
Representing Organic Structures
1. Are the following compounds isomers, the same compound or neither? (Two compounds are isomers if they have the same
molecular formula, but different structure.)
H
H
C
C
H
H
C
C
H
H
C
H
H
H
H
C
H
C
H
H
H
H
H
C
H
H
H
H
These are isomers. They have the same number of each type of atom. But they are connected in different ways
to give different structures.
2. Draw a flat picture of a six carbon alkane with the longest possible chain of carbon atoms. Indicate the name and formula.
Then rearrange the carbon chain to form an isomer.
H
H
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
C
H
H
H
H
H
H
Isomer
Longest chain
name: hexane
formula: C6H14
3. Draw a perspective line drawing and Haworth projection for cis-1,2-dichlorocyclopentane (question 1, postlab).
Cl
Cl
4. Draw flat structures for two isomers of dibromopropane (C3H6Br2) and name them.
Br
H
Br
H
C
C
C
H
H
H
1,2-dibromopropane
H
Br
Br
H
H
C
C
C
H
H
H
1,1-dibromopropane
H
(How many more isomers are there?)