Chemistry lab

Pre-Lab Questions:

1. Write the balanced equation for the decomposition of hydrogen peroxide.

MnO2

2H2 O2e -----> 2H2 Oe + O2

2. According to Charles’s law, what is the relationship between temperature and pressure?

When gas has a fixed mass and is kept at a constant pressure the temperature and volume are directly proportional to each other.

3. Atmospheric pressure depends on the altitude (or height) of your location.  How should the air pressure change if you were in Denver, Colorado, which is 1.5 kilometers (1 mile) above sea level?

The pressure decreases the higher above sea level you go, therefore the pressure in Denver, Colorado would decrease.

4. Considering that catalysts are not consumed in a reaction, how do you think increasing the amount of catalyst would affect the reaction rate for the decomposition of hydrogen peroxide?

The rate would increase.

Experiment 1: Charles’s Law

Table 1 Temperature vs. Volume of Gas Data

Post-Lab Questions

1. Use a pencil and graph paper to create a graph of temperature and volume data. Place temperature on the x-axis (in Kelvin) and volume (mL) on the y-axis. Leave room on the left side of your chart for temperature values below zero. You can also use a graphing program to create your graph. Using a ruler, draw a straight line of best fit through your data points, extrapolating the line until it intersects the (negative) x-axis.

2. Why can you assume a linear relationship (a straight-lined slope)?

Because it is 2 straight lines that intersect at a point.

3. What happened to the volume of gas when the syringe was exposed to various temperature conditions? Using the concepts explored in the Introduction, describe why this occurred, keeping in mind the definition of temperature.

It became easier to compress the air when the temperature was lowered because the average molecular energy was also lowered. On the other hand, the average molecular energy increased as the temperature was raised, making it more difficult to compress the air in the syringe.

4. At what temperature does your line intersect the x-axis? What volume corresponds to this temperature?

276 K , 8mL

Insert a photo of your completed lab setup with your name and access code handwritten in the background:

Experiment 2: Using the Ideal Gas Law

Table 2 Temperature, Pressure and Volume Data

Table 3 Reaction Time Data

Post-Lab Questions

1. What would happen if you added more than five mL of yeast to the H2O2?

Less O2 or bubbles would be created.

2. What would happen if you added more than 5 mL H2O2 to the 5 mL of yeast?

More o2 would be in the reaction

3. What was going on in the graduated cylinder as the H2O was pushed out?

More and more gas bubbles occured.

4. How would the number of moles (n) of O2 change if your atmosphere was doubled and all other variables stayed the same?

5. How would the number of moles (n) of O2 change if your temperature was doubled and all other variables stayed the same?

They would be decreased by 50%

6. In this experiment, the temperature of the gas evolved is equal to the temperature of the water in the beaker, which ideally should be the same as the air temperature. Explain how the volume of oxygen evolved would change if you used ice water instead of room temperature water. How would it change if you used boiling water?

If the temperature of water in the beaker was lower due to ice then the volume would decrease and if the temperature of water was hotter due to boiling water then the volume would increase.

Insert a photo of your completed lab setup with your name and access code handwritten in the background:

Lab 8 Using the Ideal Gas Law CHEM101L