Thursday, Sept. 12th: A DayFriday, Sept. 13th: B DayAgendaCheck lab write-upsLab discussion: Classifying Chemical ReactionsLab: Classifying Chemical ReactionsCompleted lab will be due next timeNext Time: Classifying Chemical Reactions lab WS & Begin Ch. 8 reviewWednesday/Thursday: Review/work dayFriday/Monday: Chapter 8 test/concept review due
Classifying Chemical Reactions Lab DiscussionBe sure to record the following in your data table:Appearance of reactant(s)Evidence of chemical reactionProperties of product(s)
This information is needed in order to write a balanced chemical equation for the reactions you will be doing.
Classifying Chemical Reactions Lab Discussion
Most common gases can be identified by testing their combustion properties (the burning splint test) and/or their acid-base properties (the litmus test).
Look at reactions 2, 3, and 4 in your lab handout.You will be testing gases that may be produced in these reactions to try to identify them.
Classifying Chemical Reactions Lab DiscussionCarbon dioxide gas, CO2, is more dense than air and DOES NOT support combustion. A burning wood splint will be extinguished if inserted into a test tube containing CO2 gas.Oxygen gas, O2, is necessary for combustion reactions to occur. A glowing splint placed in an oxygen atmosphere should reignite and burn brightly.
Classifying Chemical Reactions Lab DiscussionHydrogen gas, H2, is less dense than air and is flammable. When a burning splint is exposed to H2, a loud pop is usually heard as the H2 explodes and the flame is extinguished.We will not do reaction #3, which would have generated ammonia gas, NH3. However, you still need to write the reaction and predict the products on the back page.
Lab: Classifying Chemical ReactionsReaction #4 is actually a double displacement reaction AND a decomposition reaction. These are the unbalanced reactions for reaction #4 on the back of your lab handout.1. CaCO3 + HCl CaCl2 + H2CO3 (carbonic acid)(double displacement)
H2CO3 CO2 + H2O (decomposition)
Classifying Chemical ReactionsLab DiscussionThe product from reaction #5 contains solid copper metal which will clog the drains. Pour the mixture on paper towels and dispose of in the lab garbage can. The rest of the reactions mixtures can be poured down the drain with plenty of water.After you finish each reaction, wash out your test tubes in the sink and put back in the test tube rack upside down so they can dry.
Classifying Chemical ReactionsLab Safety ItemsBunsen burners will be used tie hair back!Ethyl alcohol is flammable. Follow directions for reaction #8 exactly!HCl and NaOH solutions are both corrosive liquids. Clean up all spills immediately and rinse spills with plenty of water.Never touch chemicals directly use the droppers and spatulas provided.
Lab: Classifying Chemical Reactions
Have and be safe in the lab!
Be sure to ASK if you have any questions.
When you finish in the lab, clean up, wash hands and begin the post-lab questions on the final page of the lab.