Question

Help with these four analytical chemistry problems. I don't know how to do it and would like to know how to do it along with the correct answer to prepare myself for my exam

Note: Show all your work to eam full credit. Type or write your answers neatly and in logical order. 1. (5 points) Decide which of the following expresses precision and which expresses accuracy? Standard deviation Absolute error Variance Percent relative error Percent relative standard deviation 2. (5 points A government chemist has performed a gravimetric analysis for chloride ion on a sample submitted to the laboratory. Multiple measurements revealed the following results for the of chloride: 24.45, 24.52, 24.10, 24.32, 24.17, 24.21, 24.26 Find: (a) the average (b) the standard deviation (c) 90% confidence interval (d) 99% confidence Interval

Answer 1

1. Accuracy means measurements that are close to the known value and precision means that are close to each other or it refers to how close two or more measurements are to each other, regardless of whether those measurements are accurate or not. On the basis of definition the Absolute error, percent relative error are expresses accuracy and standard deviation, variance, percent relative standard deviation are expresses precision.

干. 2432 sef foint 24.4S 24.S2. 24.lo 24. 32 -文12 24.45-24-31/1ootc 24.S2-24 31/ o.04 01 ¢ 231243)2 o 24 17 /241? -2y 32o.21 wheri a 24 26 2623112 0 0036 6-z Stan dand duction for ence 2 3 - o 08 '637 Hence H phr and bouned b.363 13 N7 Lowen bound is - 14-32 - o.137 24 183