Chem 2/L ChemistryActivity Number 2ALKANES

I. Objectives:1. To describe some important physical and chemical properties of a representative of an alkane (butane) after performing some chemical tests.2. To describe some characteristics properties of alkanes or saturated hydrocarbons. Materials: Butane from butane lighter 1 piece carbon paper 0.01 M KMnO4 1 M H2SO4 bromine solution Math 4 test tubes with stopper Test tube rack 2 pipets Test tube brush Small basin Graduated cylinder 50-ml beaker 1 dropper

Procedures:A. Collection of butane sampleCollect butane in four tubes from a butane lighter by water displacement.1. Place the test tubes and stoppers in the water basin. Fill each test tube with water up to the brim. Invert the over the water and see to it that no air bubbles form inside the test tube.2. Submerge the butane lighter under water. Place the valve under the mouth of the test tubes and open it. Slowly release the gas by opening the valve and collect the gas by water displacement. Cover each test tube with rubber stopper once all the water has been displaced. Do this while the mouth of the test tube is still submerged under the water.

B. Properties of Butanea. CombustibilityGet the last sample of the butane collected. Get ready with a lighted match. Remove the stopper of the test tube and ignite the gas. b. Reaction with acidified potassium permanganateGet a sample of the collected gas and get ready with a medicine dropperFill the dropper with acidified KMnO4, remove the stopper of the test tube and immediately add the acidified KMnO4 to its content. Shake well.c. Reaction with bromine1. Get two test tube of the collected gas. Open one test tube at a time and immediately add one ml of bromine solution to each tube. Place the stopper on each test tube.2. Wrap a carbon paper around one test tube and keep it inside the room. Place the unwrapped test tube under sunlight.3. Observe both test tubes after 7-10 minutes. Un-wrap the other test tube at the same time to make your observation for the test tube exposed to the light.Record all your observations and answer the questions for research.

II. Questions for research:

1. Butane in the lighter barrel is in the liquid phase. In what phase does it exist when you collected it? Explain what had happened. Explain why butane easily undergoes a change in phase.2. Is the gas combustible? Describe the characteristics of the flame produced?3. Write the chemical reaction for the complete combustion of the butane.4. Describe and explain your observation for the reaction of butane to an acidified KMnO4.5. Describe and compare your result and observation for the two test tubes in the reaction of butane with bromine. Explain your observations.

II. METHODOLOGY

Following the schematic diagram below will show the flow of the activity II by how it was done.

1. Preparation of the Materials 1.a Preparation of the laboratory materials needed1.b Preparation of butane lighter

2. Collection of Sample

2.a Filling the small basin with water

2.b Filling the test tubes with water thatll be used for water displacement [there must be no air bubbles present inside the tubes.]

2.c Starting the water displacement method by submerging the test tubes to the small basin with water

2.d Collecting the butane gas with water displacement method

2.e Finalizing the collection of butane gas and preparing it for the tests for its properties

3. Properties of Butane

A. Combustibility

3.A.a Preparing the lighted match stick for the combustibility test of butane gas

3.A.b Igniting the butane gas with a lighted match stick [Top Most Left and Right]; thus producing an orange flame [Bottom Centre]

B. Reaction with acidified potassium permanganate 3.B.a Preparing the potassium permanganate

3.B.b Acidifying one (1) mL potassium permanganate (KMnO4) by adding two (2) drops of H2SO4

3.B.c Adding the acidified potassium permanganate [Left] to the butane gas sample; and observing the reaction(s) gained by the test [Right]