C 9. The actual length of a substance is 25m, but different three students measure four times and got the following result. Student A: 25.1m, 24.95m,25.01m and 24.97m Student B: 18.1m, 17.95m, 18.01m and 17.97m Student C.20m, 29m 23m and 32m Whose measurement is more precise but not accurate? A. Student A B. Student B C. Student C D. all 10. Which of the following is diatomic molecule? A.03 B. CO C. N 2 D. P4 11. How many neutrons, proons and electrons are there in atom of element 14 consecutively? A.7.7 and 7 B. 14, 7, and 7 C. 7,14,7 D. 7 7 and 14 7N
