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化学 高校生

【英語ですみません】最後の12番は何を書いたら良いのでしょうか…? Video C の実験では、aqueous solution にlead(ii) nitrate, aqueous solution にPottasium iodide を入れていました。 2KI (aq)... 続きを読む

With lead (I) nitrate solution. This precipitation reaction produces a bright yellow solid. (point values in parentheses) Part 1: 1. Copy the unbalanced reaction below into your lab notebook. Balance the reaction by adding coefficients. (1) KI (aq) Pb(NO,), (aq) KNO, (aq) Pbl, (s) 2. a) Which trial are you assigned? b) Copy the data table below into your notebook. Watch video A (make sure it's the correct trial!) and collect your data. You may need to pause or rewatch the video, it goes quickly. (1.5) Mass of Empty Beaker (g) Mass of Beaker+ solid Pb(NO,)。(g) Volume of 1.0 M KI (aq) (mL) For the following calculations, show all your work for full credit. 3. What mass of solid Pb(N0,), was added to the beaker? (1) 4. If the solid Pb(NO,), was dissolved in 45 mL of water, what is the molarity of the Pb(NO,)。 solution? (2.5) 5. Which compound is the limiting reactant? (4) 6. What mass of lead (II) iodide (PbL,) should be produced? (2) Part 2: 7. Watch video B (make sure it's the correct trial!) to see the complete reaction and collection of the product. Copy the data table below and record your data. (1) Mass of filter paper (g) Mass of filter paper + dried precipitate (g) 8. What mass of precipitate was collected? Show your work. (1) Calculate the percent yield for the reaction. Show your work. (2) 10. For your trial, which three ions were present in the filtered solution at the end of the reaction? In other words, which three ions are still dissolved at the end of the reaction? Defend/explain your 9. answer. (3) 11. Watch video C - watch both tests for your trial and record your observations. (1) a) Add lead (II) nitrate - b) Add potassium iodide - 12. These tests were conducted to prove the identity of the limiting reactant. Considering your answers to the previous two questions, describe how these tests support the prediction you made in question 5 about which compound is the limiting reactant. (2)

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英語 高校生

BとDを教えてほしいです

Suppose you were asked to participate in a blind taste-test of five different brands of strawberry jam. After tasting all of the jams, but before being asked to rate their quality, you spend a couple of minutes ( I 1 ) down your reasons for liking and disliking each jam. Then you rate each one on a scale from 1 to 9. How accurate would your ratings be, assuming we judged accuracy by comparing your ratings with those given bya panel of experts assembled by Consumer Reports magazine? When psychologists Timothy Wilson and Jonathan Schooler conducted this experiment with college students as their subjects, they found that the ratings the students gave to the jams had almost no resemblance to , those given by the experts. 2 They should have been able to tell which ones were good and which ones were not the jams varied widely in quality and included those ranked 1st, 11th, 24th, 32nd, and 44th best out of 45 that Consumer Reports had reviewed. Did the students have no taste for jam? Did their preferences differ from the experts'? Not at all. In a separate condition of the experiment, rather than writing the reasons they liked and disliked each jam, each subject wrote about something entirely ( 4 ): their reasons for choosing their college major. The subjects then rated the jams, and despite not having thought about them at all after tasting them, they made ratings that were much closer to those of the experts.

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