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TOLAY IN HISTORY
November 2nd
On this day in 1977, a report by Carl R. Woese was published that identified
methanogens, an ancient life form that has existed on Earth for 3.5 billion
years. Woese studied the unicellular organisms and discovered they lived in
oxygen-deficient environments and survived by reducing carbon dioxide to
methane. In the report, Woese stated these organisms were so different from
other living things that we should change the classification system and place
methanogens in a new and separate domain, Archaea.
Phylogenetic Tree of Life
Questions:
1. If these were one of the first organisms to
live on Earth, what kind of conclusions can
we make about conditions on Earth
billions of years ago?
2. Do you think it's possible that we will
discover other unique and different
organisms that require modification of the
current classification system?
Bacteria
Archas
Eucarya

Which atom or ion is the largest? 0 a. 0 0 0 0 e. li

Experiment: effect of solution concentration on reaction rate you have learned that as the concentration of reactants increases, there will most likely be a greater number of collisions, and hence increase the rate of a reaction. in this experiment, you will see a demonstration of this, with a twist. there will be three reactions going on in this experiment. objectives determine how solution concentration can affect the rate of a reaction. the first reaction will be a reaction of the iodide ion (i-1) with hydrogen peroxide (h2o2) in an acidic solution. this reaction produces a slightly orange solution. in our experiment, we will add some orange food coloring to make this solution more orange. 2 h+ (aq) + 2 i- (aq) + h2o2 (aq) ⟶ i2 (aq) + 2 h2o (l) the next reaction will be between the iodine and starch i2 + starch ⟶ i2-starch complex (blue-black) so, when starch is added to the iodine solution made from the first reaction, the solution will turn black immediately, so it is difficult to find the rate of reaction. in order to be able to time this reaction, you will slow it down with another reaction. adding ascorbic acid will react with the iodine, reducing the concentration of the iodine available to react with the starch. c6h8o6 (aq) + i2 (aq) ⟶ 2i- (aq) + c6h6o6 (aq) + 2 h+ (aq) when the ascorbic acid is used up, the remaining iodine molecules can react with the starch and form the black color. the more ascorbic acid you add, the slower the reaction to form the iodine-starch complex will be. use your data and observations to complete the assignment. analysis and conclusions submit your data and the answers to these questions in the essay box below. what was your hypothesis? plot your data as drops of ascorbic acid vs. time. as the concentration of ascorbic acid was increased, did the rate of the formation of the iodine-starch complex increase or decrease? explain your answer in terms of the chemical reactions involved. was your hypothesis correct? make a general rule about the effects of concentration of reactants on reaction rates. for practice, the molecular formula for ascorbic acid is c6h8o6, and you used 6 g in this experiment, calculate the molarity of the ascorbic acid. now calculate the concentration in moles per drop (assume 1 ml = 20 drops).

Which scientists contributed to the determination of how cfcs in clouds in the upper atmosphere could destroy ozone molecules