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自然科學 大學

想問3-9的a跟c

Problems 3-1. Explain the difference between *(a) random and systematic error. (b) constant and proportional error. *(c) absolute and relative error. (d) mean and median. *3-2. Suggest two sources of systematic error and two sources of random error in measuring the length of a 3-m table with a 1-m metal rule. 3-3. Name three types of systematic errors. *3-4. Describe at least three systematic errors that might occur while weighing a solid on an analytical balance. *3-5. Describe at least three ways in which a systematic error might occur while using a pipet to transfer a known volume of liquid. 3-6. Describe how systematic method errors may be detected. *3-7. What kind of systematic errors are detected by varying the sample size? 3-8. A method of analysis yields masses of gold that are low by 0.4 mg. Calculate the percent relative error caused by this result if the mass of gold in the sample is (a) 500 mg. (b) 250 mg. V(c) 125 mg. (d) 60 mg. 3-9. The method described in Problem 3-8 is to be used for the analysis of ores that assay about 1.2% gold. What minimum sample mass should be taken if the relative érror resulting from a 0.4-mg loss is not to exceed *(a) -0.1%? (b) -0.4%? (c) -0.8%? (d) - 1.1%? 3-10. The color change of a chemical indicator requires an overtitration of 0.03 mL. Calculate the error if the total volume of titrant is percent relative (a) 50.00 mL. (c) 25.0 mL. 3-11. A loss of 0.4 mg of Zn occurs in the course of an percent relative analysis for that element. Calculate the error due to this loss if the mass of Zn in the sample is *(b) 10.0 mL. (d) 30.0 mL. 190 (c) 188 (d) 4.52 x 103 4.63 x 103 4.53 x 10 ³ √6 *(a) 30 mg. (b) 100 mg. *(c) 300 mg. (d) 500 mg. 3-12. Find the mean and median of each of the following sets of data. Determine the deviation from the mean for each data point within the sets, and find the mean devi- Vation for each set. Use a spreadsheet if it is convenient. *(a) 0.0110 0.0105 (b) 24.53 0.0104 24.68 24.81 24.77 39.61 862 (f) 850 MA 3-13. Challenge Problem: Richards and W the molar mass of lithium and colle data. 24.73 Experiment 1 2 3 4 5 6 194 447 X 10 7 448 X 107 4.58 X 10 (a) Find the mean molar t workers. (b) Find the median molar ma (c) Assuming that the cam molar mass of lithium is the absolute ertor and of the mean value demi Willard. (d) Find in the chemical ues for the molar mus since 1910, and ag a table or spreadshera 1817 given in the a Richards and Willd. Com mass versus year to la of lithium has chang Suggest possible abruptly about 18 ant de (e) The incredibly deals Richards and W that major changes will occur. Disc calculation in pat (f) What factors ha since 1910? (g) How would you mass? 6See Chapter 2 of Applications of Microsoft Excel in Analytical Chemistry, 4th ed., for information about statistical 7T. W. Richards and H. H. Willard, J. Am. Chem. Soc., 1910, 32, 4, DOI: 10.1021/ja01919a002. built-in statistical functions. "Answers are provided at the end of the book for questions and problems marked with an asterisk The I of ₂ or inc rce of able vas error c often in individu ate resul data in rtainties. dimensio andom e analysts The result

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英文 國中

幫我解答全部題目答案,因為我全部都不會

9 2108 Bunun DAL jo y w S M uu un IN Os 31 3 10 6.95 CINGO TAL •ung 1 can may 42-4 英語科 第 4 次複習考 93 82 L1-2 、單題:請依文意選出一個正確或最佳的答案。 (1~5題每題2分,6~15期每週3分,共40) () 1 Peter in the evening. (A) watches TV ( plays soccer (C) does exercises D uses computer () 2 There is little rain this summer, so the water problem now. ( facing D) working 3 There was something wrong with my took me to the dentist. (B) ear A tooth (C) eye (D) leg () 4. Which is your favorite running or football? (B) tricks (D) sports we are (A) playing (C) saving A things (C) stories () & Does the washing machine (A) save () 6 Ken. every day. (A) does (B) be () 7. Many people think () 14 1 three times a week. (A) always () 9. The girl (A) have EST TW ? I can't turn it on. (B) play (C) change (D) work play the piano very well. He practices it day. It gives you power to start a new day. (A) breakfast (B) lunch (D) menu (C) dinner () & My brother is late for school. He is late at least so my mom (C) do (D) can is the most important meal in a (C) seldom (D) never (B) often a lot of make-up on her face. (B) has (D) is WWW MAREMUDAN A 1922 m A 20 on 20111014 (B) does (D) hasn't be late, so don't wait for me. (C) is having () 10 Sam won't go to the party tonight because he is with his work. (C) tired (D) thick (A) hungry (B) poor son. He is eleven. His brother Mike is. () 11 Ted is my nine and his sister is five. (A) only (B) first ( ) 12 John, Kate's brother, (A) speaking (C) speaks () 13 My wife can cook, but she (A) can't (C) doesn't (C) very (D) small both French and German. (B) speak (D) spoke She seldom cooks. (A) need (B) may (D) have to (C) should () 15 It's time for the first class. Tim isn't here. He comes late. (A) never (B) already (C) always (D) enough 二、題組:請依所附的短文或圖表,選出一個最適當的答案。 (每題3分,共60分) (16~20) Felicia is a housewife. She 16 get up early and prepares breakfast for her family. Then, she drives her children. to school. After that, she goes back home to do the housework. 17. She cleans the living room, kitchen, and tidies the bedroom. In the afternoon, she goes to college and has some () 16 (A) have (C) have to () 17 ( children. (C) kid's ( 18 ) there have (C) there are () 19 (A) this (C) these () 20 A never (C) seldom English lessons. Then, she picks up the children from school and makes dinner. It's hard work, but 18 some good things. After her husband, Abel, comes back, he looks after the children. until they go to bed. During 19 hours, Felicia 20 goes shopping or sees a movie with her best friend, Nina. She enjoys these free hours. (21-23) 100 el 6 3 6 M 22 M ) 21. What is a tragedy? (B) has (Di has to (B) children's (D) child's (1) there has (D there is 《背面有試題 4-1》 (D) an (B) ever (D) usually 40 (A) A bad experience. (B) A difficult dish to make. (C) An easy thing to do. (D) A favorite kind of food. () 22 Which is true about the reading? Eddie invited his friends to his tasting party last Saturday. He worked hard in the kitchen and tried baking the cookies several times. However, it was a tragedy from the beginning. First, only two of his friends came. Eddie invited twenty! All the others were either sick or busy. As soon as Cindy and Mandy arrived, it started to rain heavily. Eddie set the party in the yard. When he hurried to take the food and drinks in, he fell off the stairs and hurt his knees. He felt bad about losing face in front of the girls. Then the girls tried some of his cookies. They made a face and said the cookies were INTERESTING! Eddie didn't understand how cookies could taste interesting. He tried one himself and knew right away. His chocolate cookies were not sweet. They were salty. He mistook salt for sugar. salty 7-120 college N Peo (A) Many of Eddie's friends came to his party. (B) Eddie had an outdoor tasting party last Sunday. (C) Cindy and Mandy didn't like Eddie's cookies. (D) Eddie put too much sugar, so his cookies tasted strange. 23 Why did the girls say Eddie's cookies were interesting? (A) The cookies looked interesting. (B) The cookies tasted yummy. (C) They wanted to have more of his cookies. (D) They didn't want Eddie to feel hurt.

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