Graded Assignmentsci302/303/304B: Chemistry Unit 1 Laboratory: Gas Laws

Graded AssignmentSCI302/303/304B: Chemistry|Unit 1 | Laboratory: Gas Laws

Name: / Date:
Score
/35 total pts

Graded Assignment ______

1.05 and 1.06 Lab Report

Answer the questions. When you are finished, use the associated dropbox to submit this assignment to your teacher by the due date(2/4/13)and earn BONUS POINTS!

Introduction______

Have you ever observed how a gas in a balloon acts when heated? What did you see? What questions could you ask about how changing temperature affects the gas in a balloon? (Remember, the questions you ask should be questions that can be answered by making observations.)

Developing a Hypothesis (5 pts)

1.Write a hypothesis in IF/THEN format. Be sure to do this BEFORE you begin the lab. Use what you already know about gases and balloons.

A)Write a hypothesis in if–then form that predicts what will happen if a balloon is heated.

B)Write an additional hypothesis that predicts what will happen if the gas in a balloon filled with air is cooled.

C)Propose a method for approximating the volume of gas liberated in a chemical reaction.

Data Table 1- Station #1(4 pts)

Comparison of Heated Balloon

Room temp.
(°C and K) / Heated Water temp.
(°C and K) / Diameter of balloon at room temp.(cm) / Radius of balloon at room temp.(cm) / Volume of balloon at room temp.
(cm3),
V = (4/3) πr3 / Diameter (d) of balloon after heating (cm) / Radius of balloon after heating (cm)
r= d÷2 / Volume of balloon after heating (cm3),
V = (4/3) πr3
Example Data / 19.8 °C
292.8K / 50 °C
323K / 15.25 / 7.625 / 1857
Trial 1
Trial 2
Trial 3

Data Table 2- Station #2 (4 pts)

Comparison of Cooled Balloon

Room temp.
(°C and K) / CooledWater temp.
(°C and K) / Diameter of balloon at room temp.(cm) / Radius of balloon at room temp.(cm) / Volume of balloon at room temp.
(cm3),
V = (4/3) πr3 / Diameter (d) of balloon after cooling (cm) / Radius of balloon after cooling (cm)
r= d÷2 / Volume of balloon after cooling (cm3),
V = (4/3) πr3
Example Data / 19.8 °C
292.8K / 50 °C
323K / 15.25 / 7.625 / 1857
Trial 1
Trial 2
Trial 3

Data Table 3- Station #3(2 pts)

Gas Released

Diameter of balloon at room temp.(cm) / Radius of balloon at room temp.(cm) / Volume of balloon at room temp.(cm3),
V = (4/3) πr3
Red Balloon
Green Balloon
Blue Balloon

Graphing of Data (5 pts)

2. From Part 2 of the lab activity, construct a graph that reveals the relationship between temperature (in Kelvins) and volume. Plot the manipulated (independent) variable on the horizontal axis and the responding (dependent) variable on the vertical axis. To earn full credit (5 pts), your graph needs to include the following: title, axes labels with category and unit of measurement, appropriate scale and a line of best fit- assuming a linear relationship between volume and temperature. Be sure to extrapolate your line all the way to zero K.

Copy and paste your graph HERE ~or~ upload your graph as a separate document.
Graph Analysis (5 pts)

3.Given optimal conditions, the x-intercept corresponds to where the volume would be zero and the temperature can be no lower, defined as absolute zero. Absolute zero is 0 K.

A) Compare your results to those expected (Figure E below).

B) How close to absolute zero was your intercept?

C) Why might your value be different from absolute zero?

Figure E: The line connecting experimental data points for the volumes of gases at different temperatures, expressed in °Kelvin (°K) can be extrapolated to a volume of 0. The temperature at that point is called absolute zero. °K = °C + 273°C.

Graphic Taken From:

Drawing Conclusions (10 pts)

4.Consider all parts of the experiments that you have just performed.

A)What conclusions can you make about the relationship between the volume of a gas and its temperature?

B)What conclusions can you make about the relationship between the volume of a gas and its pressure?

C)What possible variables have you not accounted for? Identify more than one.

D)As you did the procedures, is it possible that the atmospheric pressure may have changed?
If it did change over the course of your experiment, then how would your results have been affected?

Your Score / ___ of 35

Copying or distributing without K12’s written consent is prohibited.