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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

正解は2番なのですが、どういう理由でそうなるのかが分かりませんでした。詳しく教えてください!

21:03 の マ 自46% 294 長い文章 16 What does the speaker say about Abraham Lincoln's speech? 0 It was considered a complete failure. 2 It was given at a cemetery for soldiers. 3 It was nearly two hours long. の It was given a score of four out of seven. Sp The Gettysburg Address The Gettysburg Address is one of the most famous speeches in U.S. history, but when Abraham Lincoln finished delivering the speech, he thought it had been a complete failure. The speech was not even the main speech given that dov.a dedication of a cemetery for the thousands of soldiers who had died in the Battle of Gettysburg a few months earlier. After the main speaker had spoken for nearly . hours, the President spoke for only a few minutes. His speech was only ten senten.. long, but it reminded Americans why they had fought to create a new country and urged them to fight on to save it and make it greater. The reason Abraham Lincoln's speeches are so memorable is that he wrote and rewrote them until they sounded almost like poetry. For example, he ends the speeck with, “that government of the people, by the people, for+he people, shall not perish from the earth." By repeating, "of the people, by the people, for the people," he makes the phrase easy to remember. But, of course, it is the opening of the speech that even school children can recite: “Four score and seven years ago." A“score" is twenty years, so he is really saying, “Eighty-seven years ago.” But “eighty-seven years ago" doesn't sound very poetic, does it?

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