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1. Chapter 6 IPS Part 2 100 100 100 100 100 100 200 200 200 200 200 200 300 300 300 300 300 300 400 400 400 400 400 400 500 500 500 500 500 500

2. 100 Why did the zinc have to sit in hydrochloric acid over night? Answer:The mixture has a sit overnight in order for it all to react.

3. 200 What was the purpose of the washing water in the test tube that had the remaining zinc and HCl? Answer:Washing water in test tube allows you to remove any solution ZnCl off the zinc metal in order to add in the solution in the evaporating dish.

4. 300 When is the best time to mass the evaporating dish with its contents? Answer: Heating the solution has to continue until it dries then melts again into a liquid pool.

5. 400 How did you calculate the chloride that reacted? Answer:5 The mass of zinc reacted and – the mass of zinc chloride formed will equal the mass of Cl reacted.

6. 500 How do you calculate the mass ratio of the zinc chloride formed? Answer:mass of zinc reacted divided by mass of chlorine that reacted will provide a ratio.

7. 100 What will happen if you mass the evaporating dish too quickly with out allowing the entire process to take place? Answer:The mass of zinc chloride formed will increase the mass of Cl reacted thus decreasing the ratio.

8. 200 What happened to the ratio of zinc chloride as you added more zinc? Answer: No it was constant regardless of adding more zinc.

9. 300 If 6.5 g of zinc had been used in the experiment, what is the mass of zinc chloride, in grams, that would have been formed? Answer:13 g zinc chloride formed

10. 400 If 18 grams of zinc had been used in the experiment, what is the mass of zinc chloride, in grams that would have formed? Answer:14.5 zinc chloride would have formed

11. 500 What can you note about the graph as all the hydrochloric acid reacts? Answer: When all the hydrochloric acid forms with the zinc you can note the graph becomes horizontal with no change.

12. 100 Are you able to tell how much hydrochloric acid was used? Answer: It is difficult to state how much hydrochloric acid was used because that information isn’t provided on the graph.

13. 200 What type of reaction was 6.4? choose decomposition/Synthesis/single replacement . Answer:The type of reaction in the experiment was a single sythesis reaction.

14. 300 6.5 The Law of Constant Proportions T/F Water and zinc chloride both represent compounds. . Answer: True

15. 400 T/FWater and zinc chloride occur in constant ratio regardless of what you add to it. Answer: T Water and zinc chloride occur in constant ratio regardless of what you add to it.

16. 500 Who was the French chemist that believed that a pair of substances can combine over a range of ratio’s. Answer:Claude Louis Berthollet a French chemist believed that a pair of substances can combine over a range of ratio’s.

17. 100 Which scientist based the experiment of zinc chloride and water and suggested a new law of nature called constant proportion in 1799. Answer: Joseph Louis Proust based the experiment of zinc chloride and water and suggested a new law of nature called constant proportion in 1799.

18. 200 …nature assigns fix _______; in short, a being which nature never creates other than a _________ in hand. Answer:…nature assigns fix ratios; in short, a being which nature never creates other than a balance in hand.

19. DailyDouble! 300 Who's position does 6.6 heating of copper tend to support (Proust or Berthollet’s)? Answer: The following experiments tend to support Berthollet’s position. .

20. 400 What was the purpose of 6.6? Answer:The purpose of this experiment is investigate the reaction of finely ground copper with oxygen in the air.

21. 500 What indicated a chemical change in the experiment heating of copper? Answer:BDQ 1 as it’s heated there is a color change as oxygen reacts with copper. The mass over all increased in the reaction.

22. 100 Explain how you obtain the mass of oxygen in experiment 6.6. Answer:4 To get the mass of oxygen that reacted with copper you have to subtract Cu before – Cu and O after. This will equal the O reacted. .

23. 200 What type of reaction was copper reacting with oxygen? Answer:Cu + O CuO Synthesis reaction.

24. 300 Was this reaction 6.6 a complete reaction, explain? Answer: No you can still observe some of the copper in the formation of copper oxide.

25. 400 What is the purpose of the experiment 6.7? Answer:The purpose is to determine if the black solid is a mixture or a pure solid.

26. 500 A sample of powdered copper having a mass of 3.64 grams was placed in a crucible and heated until the mass became 3.90 g. When the copper oxide that formed was dissolved in acid, 1.70 g of copper was left. The ratio is copper before – copper oxide divided by copper before – copper left Answer: 3.64 cu – 3.9 cuo/3.64 cu – 1.7 cu after = .13 ratio

27. 100 Explain the method that can separate copper and copper oxide. Why? Answer:A good way to separate this mixture of copper and copper oxide is to place it HCl. Copper will not easily dissolve in hydrochloric acid and will precipitate out.

28. 200 Suppose you heated 3.2 g of powdered copper in air until the mass was 3.4 g. The black solid that was formed was placed in acid, and 1.9 g of copper remained undissolved. If you then added zinc to the acid solution, what mass of copper, in grams, do you predict would be precipitated out? ? Answer: 3.2 g – 1.9 = 1.3

29. 300 What is an incomplete reaction? Answer:Incomplete reactions are those that all the substances have not reacted totally such as the Cu and oxygen when heated.

30. 400 When is zinc reacting with HCl not a complete reaction? Answer: Zincand Chloride would be complete reaction as all the HCl will react with the zinc unless either the zinc or the hydrochloric acid has been used up.

31. 500 What was the mistake Berthollet made in understanding ratio’s? Answer:The mistake that Berthollet made was he thought incomplete reactions were really complete reactions such CuO. Thus having incorrect data supporting different ranges of ratios.