Kinetic Molecular Theory in Action LAB

Honors Chemistry

Background:

Kinetic Theory: The tiny particles in all forms of matter are in constant motion.

Basic Assumptions:

  1. A gas is composed of particles, usually molecules or atoms. These particles are considered to be small, hard spheres that have insignificant volume and are relatively far apart from one another.
  2. The particles in a gas move rapidly in constant motion. They travel in straight paths and move independently of each other. As a result, gases fill their containers, regardless of the shape and volume of the containers; certain gases diffuse into space without limit.
  3. All collisions are considered perfectly elastic. This means that during collisions, kinetic energy is transferred without loss from one particle to another and the total kinetic energy remains constant.

Safety:

Wear safety goggles and apron while in the lab area. Wash all leftover chemical down the sink with plenty of water. Wash your hands after completing the lab. Clean up your entire lab work area. BTB will stain your skin and clothing.

Purpose:

To observe color changes in the chemical reactions of gases and to interpret these changes in terms of kinetic theory.

Materials:

Well plate with lidColored Pencils

Cotton swabs

Chemicals: (note, new solutions should be made and put in dropper bottles each day/on longer days at lunch too)

0.4 % Bromothymol blue BTB1M Hydrochloric acid HCl

1.0 M Sodium hydrogen sulfite NaHSO30.4 M Sodium nitrite NaNO2

1.0 MAmmonium chloride NH4Cl0.5 M Sodium hydroxide NaOH

0.1 M Potassium iodide KI

Prelab:

  1. Write the postulates of KMT (see page 430 in your text book)
  2. Rearrange PV=nRT for P; V; n; R; T

Procedure:

  1. Add two drop of BTB to all of the wells EXCEPT the two center-most wells in your well plate.
  2. Into the two center-most wells, add 2 drops HCl.
  3. Into the two center-most wells, also add 2 drops of NaHSO3. QUICKLY place the lid onto your well plate.
  4. Wait and observe, record your results on the well diagrams and refer to directions at the top of the well diagram page
  5. Answer questions #1-4 (Use colored pencils where necessary).
  6. When the reaction is complete, open the lid of the well plate. Do not discard the contents of the well plate.
  7. Absorb the contents of the two center-most wells by using a Q-tip.
  8. Into the two center-most wells, add 2 drops NaOH.
  9. Into the two center-most wells, also add 2 drops of NH4Cl. QUICKLY place the lid onto your well plate.
  10. Wait and observe.Record your results on the well diagrams and refer to directions at the top of the well diagram page for reaction 1.
  11. Answer questions #5 - 7 (Use colored pencils where necessary).
  12. When the reaction is complete, empty your well plate into the disposal bucket.
  13. Rinse the well plate thoroughly with distilled water.
  14. Add two drop of KI to all of the wells EXCEPT the two center-most wells in your well plate.
  15. Into the two center-most wells, add 2 drops NaNO2.
  16. Into the two center-most wells, also add 2 drops of HCl. QUICKLY place the lid onto your well plate.
  17. Wait and observe.Record your results on the well diagrams and refer to directions at the top of the page well diagram page.
  18. Answer questions#8 – 10 (Use colored pencils where necessary).
  19. When the reaction is complete, empty your well plate into the disposal bucket.
  20. Rinse the well plate thoroughly with distilled water.
  21. Leave the well plate and lid on your lab table. Do NOT put it into your lab drawer.

Analysis:

  1. Describe in detail the changes that you observed in the drops of BTB over time for reaction 1. Record these observations on the well diagram sheet. (Refer to the specific directions listed on top of the well plate diagram results page). Use colored pencils.
  2. In several sentences describe in words what you observed.
  3. The color of the BTB drops changed even though you didn’t add a chemical directly to them. If the mixture in the two center-most wells produced a gas, would this explain the changes in the drops of BTB? Use the kinetic molecular theory to explain your answer in detail.
  4. Translate the following word equation in a balanced chemical equation: Sodium hydrogen sulfite reacts with hydrochloric acid to produce sulfur dioxide gas, water and sodium chloride. (Include state of matter) Record this on the well plate diagram sheet on the reaction 1 line.
  5. For reaction 2, describe in detail the changes that you observed in the drops of BTB over time. Record these observations on the well diagram sheet. (Refer to the specific directions listed on top of the well plate diagram results page). Use colored pencils.
  6. In several sentences describe in words what you observed.
  7. Translate the following word equation into a balanced chemical equation. Ammonium chloride reacts with sodium hydroxide to produce ammonia gas, NH3, water and sodium chloride. Record this on the well plate diagram sheet for reaction 2.
  8. For reaction 3, describe in detail the changes that you observed in the drops of KI over time. Record these observations on the well diagram sheet. (Refer to the specific directions listed on top of the well plate diagram results page). Use colored pencils.
  9. In several sentences describe in words what you observed.
  10. Translate the following word equation into a balanced chemical equation. Sodium nitrite reacts with hydrochloric acid to produce nitrogen monoxide gas, water, sodium nitrate and sodium chloride. Record this on the well plate diagram sheet for reaction 3.

KMT Lab – Well Plate Observations

For each reaction, on the line write the formulas of the chemicals that are involved in the overall reaction. Then color what the well plate looks like at the beginning, middle and end of the reaction. Record the times as the reaction occurs in the appropriate well. (In other words, once you see a color change a well of the well plate write that time interval in that well. For side views record times when observed and color them as seen from each side view.

Reaction 1:______

Colored Well Plate – Beginning of Reaction Well Plate – Transition – with times listed at the beginning of change in each well

Time: 0

Colored Well Plate –In Middle of Reaction when Side View in Middle of Reaction when

50% of wells have changed color 50% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

Colored Well Plate – At end of the Reaction when Side View at end of the Reactionwhen

100 % of wells have changed color 100% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

KMT Lab – Well Plate Observations

Reaction 2:______

Colored Well Plate – Beginning of Reaction Well Plate – Transition – with times listed at the beginning of change in each well

Time: 0

Colored Well Plate – In Middle of Reaction when Side View in Middle of Reaction when

50% of wells have changed color 50% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

Colored Well Plate – At end of the Reaction when Side View at end of the Reactionwhen

100 % of wells have changed color 100% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

KMT Lab – Well Plate Observations

Reaction 3:______

Colored Well Plate – Beginning of Reaction Well Plate – Transition – with times listed at the beginning of change in each well

Time: 0

Colored Well Plate – In Middle of Reaction when Side View in Middle of Reaction when

50% of wells have changed color 50% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

Colored Well Plate – At end of the Reaction when Side View at end of the Reactionwhen

100 % of wells have changed color 100% of wells have changed color

Time______Time______

Side View- Width

Side View - Length

KMT Lab Rubric (69 pts)

_____ 2ptsObjectives: Clearly stated and explained in terms of what will be performed in this lab. Lab listed in table of contents.

_____ 5 ptsAll questions answered in complete sentences with question listed or rephrased

_____ 8ptsLab physically completed within one week of assigned date

_____ 5 ptsPre lab question 1: Write the postulates of KMT (see page 430 in your text book)

_____ 4ptsRearrange PV=nRT for P; V; n; T

_____ 8ptsAnalysis Q1: Reaction 1 well plate diagrams completely filled in

_____ 2ptsAnalysis Q2: Color progression for reaction 1 is clearly described in words.

_____ 6ptsAnalysis Q3: Clearly identifies the gas that was produced in this reaction. Color

progression is clearly explained in terms of the KMT assumptions.

_____ 3ptsAnalysis Q4: Balanced equation for reaction 1 is provided with state of matter included.

_____8ptsAnalysis Q5: Reaction 2 well plate diagrams completely filled in

_____ 2ptsAnalysis Q6: Color progression of reaction 2 is clearly described in words.

_____3ptsAnalysis Q7: Balanced equation for reaction 2 is provided with state of matter included.

_____8ptsAnalysis Q8: Reaction 3 well plate diagrams completely filled in

_____ 2ptsAnalysis Q9: Color progression of reaction 3is clearly described in words.

_____3ptsAnalysis Q10: Balanced equation for reaction 3 is provided with state of matter included.