4. Chemical Reactions
Investigate Chemical Reactions!
Sue Boudreau 4.26.2011
Learn how to collect gases. Learn how to test for three common gases. Use your evidence to figure out the word
equations for the reactions you observe. Balance your chemical equation like a professional chemist. See chapter 8.2 to
help you after you do your best.
1. Hydrogen + Oxygen balloon + flame in air -> ____________________ ____________________
a. Predict:
b. What happened?
c. What are the products?
d. Write the equation with chemical symbols and formulas (subscript numbers).
Reactants
Products
_________________ + __________________ -> ___________________
e. Use the molecule models (or your algebra skills) to add in ‘co-efficients’ to make a balanced equation:
_________________________________________________________________________________
2. Gas tests: Observe, draw, note so you’ll remember what to do when it’s your turn.
CO2
O2
H2
SAFETY REMINDERS: Write in what you have to remember when doing your own gas tests.
3. Sugar + Oxygen fed to yeast -> _________________ + ____________________
a. Predict:
b. Procedure and safety notes:
c. What happened?
e. What are the products?
f. Write the equation with chemical symbols and formulas (subscript numbers).
Reactants
Products
_________________ + __________________ -> ___________________
g. Use the molecular models (or your algebra skills) to add in ‘co-efficients’ to make a balanced equation:
_________________________________________________________________________________
h. What is the name of this process? __________________________________________________
i. What are the catalysts in living things called?____________________________________________
j. Where are the catalysts for this process found in cells like yeast and in us? ____________________________
4. Wood (Wood is made of cellulose which is a polymer of sugars C6H12O6)+ Oxygen -> ___________+__________
a. Predict:
b. Procedure and safety notes:
c. What happened?
e. What are the products?
f. Write the equation with chemical symbols and formulas (subscript numbers).
Reactants
Products
_________________ + __________________ -> ___________________
g. Use the molecule models (or your algebra skills) to add in ‘co-efficients’ to make a balanced equation:
_________________________________________________________________________________
5. Methane (natural gas, the smallest ‘hydrocarbon’ ) + Oxygen -> __________________ + ___________________
a. Predict:
b. Procedure and safety notes:
c. What are the products?
d. Write the equation with chemical symbols and formulas (subscript numbers).
Reactants
Products
_________________ + __________________ -> ___________________
e. Use the molecule models (or your algebra skills) to add in ‘co-efficients’ to make a balanced equation:
_________________________________________________________________________________
6. Carbon (briquette) +air -> ___________________________ + ______________________
a. Predict:
b. Procedure and safety notes:
c. What happened?
d. What are the products?
e. Write the equation with chemical symbols and formulas (subscript numbers).
Reactants
Products
_________________ + __________________ -> ___________________
f. Use the molecule models (or your algebra skills) to add in ‘co-efficients’ to make a balanced equation:
7. Baking Soda and Vinegar reaction. NaHCO3 + HC2H3O2
Predict what’s going to happen. Predict the products of the reaction.
What gas was given off? ___________________________
What happens to the color of the indicator in the vinegar by the end of the reaction? ___________________________
Read chapter 8.2.
Write a balanced equation for this reaction:
______________________________________________ ______________________________________
What might affect the RATE of this reaction?
_____________________________________________________________________________________________
8. Zinc + HCl acid.
Predict what will happen.
What did happen?
Based on the results, write the chemical equation and balance it.
______________________________________________ ______________________________________
What might affect the RATE of this reaction?
_________________________________________________________________________________
3. Do the review questions for chapter 8.2. Due TOMORROW.
Chemical Reactions Stochiometry Labs Teaching Notes:
Equipment needed
Consumables:
H2 cylinder
O2 cylinder
Zinc bits
Dil HCl in squirt bottles.
Hydrogen peroxide FRESH
Yeast and/or ground meat as catalyst.
Sugar
Briquettes
Warm water
Bromothymol blue indicator
Helium grade balloons
Matches, splints.
Hair ties
Demo equipment:
Water electrolysis glass ware, graphite electrodes, salt water, DC power transformer 12V, leads with alligator clips.
Candle, spills, matches.
Per table group equipment:
Cylindrical flask, cork with tubing
Test tube with cork
Plastic water bath
Splints
Candle and holder or use Bunsen flame. Both have safety hazards.
BTB in dropper bottle
Small beaker for BTB + water.
4 goggles.
Oven mitt, tongs
Clipboards
Safety and procedure notes:
Special care with trip hazards, hair, sleeves etc.
Use a long stick for the H balloon and a candle at a distance. Only fill balloon to about 4” diameter or do outside with
kids way back.
Use the baking soda + vinegar reaction to get CO2 if no cylinder of the gas.
When collecting gas from burning things like coal and wood, use a wide-necked flask. Take care NOT to touch the neck
of the flask as it gets very hot. Quench both in a water bath in the sink.
Throw matches and used splints into the sink or have a beaker of water for quenching. Do NOT throw in the trash.
The yeast + sugar takes awhile. Use warm water. Stand in warm water. Start at the start of class. Have an extra demo
that has run over night. Hide it before class. Reveal after they predict.
Yeast + Hydrogen Peroxide takes awhile too. Use 20ml hydrogen peroxide and a spatula of yeast in a test tube. Put in
warm water. Wait til it fizzes. Shake gently. Have a big demo in a flask at the front too.