LAB DEMO ACTIVITIES
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Transcript of LAB DEMO ACTIVITIES
LAB DEMO ACTIVITIES
1. Blue Bottle2. Foam Column3. Solid Reaction4. Flame Tests5. Burning Magnesium6. Carbon Pillar
Skills Focus:
Making Observations
Qualitative vs. Quantitative
Aim: To find out the different signs of a chemical change.
Qualitative observations use your senses to observe the results. (sight, smell, touch, taste and hear.)
Quantitative observations are made with instruments such as rulers, balances, graduated cylinders, beakers, and thermometers. These results are measurable.
CHEMICAL CHANGES
Lab Demos
1. Blue Bottle•Measure 5g Dextrose•Measure 5g NaOH pellets•Add to 250ml water•Place ¼ drop 1% methylene blue•Conical flask•Stopper•Shake the flask until NaOH is dissolved•Wait
2. Foam Column
•Potassium Permanganate (flat spoonful)•Squirt of detergent - enough to cover the KMnO4•30-50ml of hydrogen peroxide (slowly add)
3 4. Flame Tests
Different solutions of metal salts
• Observe what happens when the solution is ignited.
6. Carbon Pillar
• 40ml white sugar• H2SO4• Small beaker (80ml)• Enough of the H2SO4 to cover the
sugar
5.
Evidence of chemical reactions
Lab Demo Diagram Observations
1
2
3
Part A - Observations
Evidence of chemical reactions
Name Diagram Observations
4
5
6
Part B - Indications of chemical reactionMake a list of all the observations from above that indicates a chemical reaction has taken place.
FLAME TESTSRelease of
Light Energy
Li
FLAME COLORS
When ignited, metal particles get excited
and when it goes back to its ground state
release energy in the form of light.
Metal Salts Flame Color
Calcium chloride Yellowish red
Strontium chloride Scarlet red
Sodium chloride Bright yellow-orange
Potassium chloride Lilac
Barium chloride Pale green
Lithium chloride Carmine red (less intense red)
Metal salts introduced into a flame give off light characteristic of the metal.
1. Blue Bottle•Measure 5g Dextrose•Measure 5g NaOH pellets•Add to 250ml water•Place ¼ drop 1% methylene blue•Conical flask•Stopper•Shake the flask until NaOH is dissolved•Wait
2. Foam Column
•Potassium Permanganate (flat spoonful)•Squirt of detergent - enough to cover the KMnO4•30-50ml of hydrogen peroxide (slowly add)
3.Burning Magnesium
•2cm of Mg•Hold in tongs•Ignite
• color change• reversible reactions
• Gas and heat
• light and change in form; new substance
5. Solid Reaction• 1 test tube containing Potassium
Iodide• 1 test tube containing Lead Nitrate• Pour the KI into a conical flask• Carefully lower the test tube of
PbNO3 into the flask• Place on stopper• Place on balance and zero• Tilt flask to spill the PbNO3
• change in color• change in state
7. Carbon Pillar
• 40ml white sugar• H2SO4• Small beaker (80ml)• Enough of the H2SO4 to cover the sugar
•Gas formation •change in color• change in state• change in temp
SUMMARY
From the 6 demos, the following are signs of a chemical reaction: • • • •
These signs are seen in the …. (cite examples from the demos)
AssessmentItem Assessment Criteria Point
sStudent
Evaluation
Instructor
Evaluation
Performance
Accurately recorded observations for all (8) activities 4
Labeled diagrams clearly illustrates set-up for the labs 4
Summary conclusion accurately describes signs of a chemical reaction
2
TOTAL (out of) 10
SIGNS OF CHEMICAL RXNS Color change - new substances might reflect different colors of light. Heat change - the container may get hotter or colder. Gas produced - bubbles or smoke may be observed. Precipitate formed - an insoluble solid might form in a liquid.
Chemical RXNs
Reactants Products
Parts of a rxn: Reactants
•Substances that interact with each other; left side of the arrow in a chemical equation. Products •New substances formed during a reaction; right side of the arrow in a chemical equation.
A + B CC A + B
A + BX AX + BAX + BY AY + BX
FORM
SEPARATE
SWITCH 1
SWITCH 2
Mg + O2
Chemical Reaction
+
Mg + O2
Chemical Reaction
+
Mg O
Bright Light
•WORD EQUATION•CHEMICAL EQUATION
REACTION OF COPPER POWDER
REACTION OF COPPER POWDER
Copper Oxide
(2CuO)Pesticide
Fungicide
2Cu + O2 (2CuO)