NC Chemistry Project (Homework)

James Finch

Chemistry - HS, section 1st period, Fall 2010

Instructor: Dr. Friendly

Current Score: 6/19

Due: Saturday, October 23, 2010 18:00 EDT

Question

Points

1	2	3	4	5	6	7	8	9
1	1	1	1	1	1	0/11	0/1	0/1

Total

6/19

Description

Here are some questions from NC Chemistry Project with support from North Carolina Department of Public Instruction. Click here for a list of all of the questions coded in WebAssign.

Instructions

This quiz covers all the material from our phase changes studies.

1. 1/1 points All Submissions Notes Question: ncchem 3.1.006.

Question part

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1
1
1/50

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1/1

What effect does lowering the pressure on the surface of water have on the boiling point?

It decreases the boiling point. It increases the boiling point. The boiling remains the same.

Your answer is correct.

2. 1/1 points All Submissions Notes Question: ncchem 3.1.015.

Question part

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1
1
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1/1

How does the average speed of gas molecules change as the molar mass of the gas increases?

3. 1/1 points All Submissions Notes Question: ncchem 3.1.018.

Question part

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1
1
1/50

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1/1

In a closed container, what happens to the vapor pressure inside the container if more liquid is added to the container at constant temperature? Assume there was enough liquid initially present to establish equilibrium.

4. 1/1 points All Submissions Notes Question: ncchem 3.1.022.

Question part

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1
1
2/50

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1/1

Which of the following represents the highest potential energy state?

5. 1/1 points All Submissions Notes Question: ncchem 3.1.024.

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1
1
1/50

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1/1

Which of the following represents the lowest potential energy state?

6. 1/1 points All Submissions Notes Question: ncchem 3.1.028.

Question part

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1
1
1/50

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1/1

Iron has a specific heat of 0.450 J/g

°C. How much energy is required to raise the temperature of 295 g of iron from 12.0°C to 153.0°C?

WebAssign will check your answer for the correct number of significant figures.

7. –/11 points Notes Question: ncchem 3.1.050.

Question part

Points

Submissions

1	2	3	4	5	6	7	8	9	10	11
0/1	0/1	0/1	0/1	0/1	0/1	0/1	0/1	0/1	0/1	0/1
0/50	0/50	0/50	0/50	0/50	0/50	0/50	0/50	0/50	0/50	0/50

Total

0/11

The phase diagram for carbon dioxide is shown below.

(1) Type your answer for physical states using the format of g for gas, l for liquid, and s for solid. If more than one physical state is present, enter the physical states separated by a comma.
(2) Type your answer for trends using the format of increase, decrease, remains constant.
(3) Type your answer for changes in physical state, for example solid to liquid to gas, using the format s>l>g.

(a) What physical state(s) is/are present at 50°C and 100 atm?
Answer is not case sensitive.
1
(b) What physical state(s) is/are present at -78°C and 1 atm?
Answer is not case sensitive.
2
(c) What physical state(s) is/are present at -90°C and 10 atm?
Answer is not case sensitive.
3
(d) What physical state(s) is/are present at 25°C and 73 atm?
Answer is not case sensitive.
4
(e) What physical state(s) is/are present at the triple point?
Answer is not case sensitive.
5
(f) How does the melting point change with increasing pressure?
Answer is not case sensitive.
6
(g) How does the boiling point change with increasing pressure?
Answer is not case sensitive.
7
(h) What change(s) in physical state occur if carbon dioxide at 10°C and 1 atm is cooled to -90°C and 1 atm?
Answer is not case sensitive.
8
(i) What change(s) in physical state occur if carbon dioxide at -60°C and 5.2 atm is changed to -60°C and 0.1 atm?
Answer is not case sensitive.
9
(j) What change(s) in physical state occur if carbon dioxide at 50°C and 73 atm is cooled to -78°C and 73 atm?
Answer is not case sensitive.
10
(k) What change(s) in physical state occur if carbon dioxide at 25°C and 5.2 atm is pressurized to 25°C and 70 atm?
Answer is not case sensitive.
11

8. –/1 points Notes Question: ncchem 3.1.051.

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0/1
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0/1

Which of the following increase the vapor pressure of a liquid? (Select all that apply.)

decreasing intermolecular forces decreasing temperature increasing the volume of the container increasing intermolecular forces increasing temperature

9. –/1 points Notes Question: ncchem 3.1.054.

Question part

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0/1
0/50

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0/1

Some physical properties of water are shown below.

melting point	0.0°C
boiling point	100.0°C
specific heat solid	2.05 J/g°C
specfic heat liquid	4.184 J/g°C
specific heat gas	2.02 J/g°C
H° fusion	6.02 kJ/mol
H° vaporization	40.7 kJ/mol

How much energy is released when 14.3 g of gaseous water at 100.0°C is converted to solid water (ice) at 0.0°C?

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NC Chemistry Project (Homework)

Current Score: 6/19