Midterm

Question 1

electrolyte

Answer 1

substance tat dissociates into ions in solution, can be strong or weak

Question 2

weight percent

Answer 2

mass of solute/mass of total solution x100%

Question 3

parts per million

Answer 3

ppm= mass of substance/mass of sample x 10^6

Question 4

parts per billion

Answer 4

ppb= mass of substance/mass of sample x 10^9

Question 5

distilled water

Answer 5

boiled to separate from less volatile impurities

Question 6

deionized water

Answer 6

passed through column that removes ionic impurities

Question 7

analytical concentration

Answer 7

moles of solute delivered to 1 L of solution, total concentration

Question 8

species concentration

Answer 8

moles of the species in 1 L of solution at equilibrium

Question 9

gravimetric analysis

Answer 9

chemical analysis based on weighing a final product

Question 10

systematic/determinate error

Answer 10

reproducible inaccuracy made by faulty equipment design, sign/magnitude the same every time, can be detected and corrected through calibration

Question 11

random/intermediate error

Answer 11

measure of fluctuation in results after repeated experiments, follows normal distribution, cannot correct but can account for with statistics

Question 12

gross error

Answer 12

outliers, caused by human/instrumental mistake, can be eliminated

Question 13

precision

Answer 13

reproducibility of results, answers may be wrong but all in same area, result of random error

Question 14

accuracy

Answer 14

deviation from “true” value, result from systematic error, can determine magnitude if standard is availible

Question 15

absolute uncertainty

Answer 15

margin of uncertainty associated with a measurement, has units

Question 16

relative uncertainty

Answer 16

absolute uncertainty/magnitude of measurement, unitless

Question 17

propagation of error- addition/subtraction

Answer 17

eT^2=eA^2+eB^2

Question 18

propagation of error- multiplication and division

Answer 18

eT/T=(eA/A)^2+(eB/B)^2

Question 19

relative standard deviation

Answer 19

Sr=s/mean

Question 20

coefficient of variation

Answer 20

S%=(s/mean)x100%

Question 21

variance

Answer 21

v=s^2

Question 22

standard deviation of the mean

Answer 22

measure of uncertainty of the mean, Ux

Question 23

F test

Answer 23

determines whether 2 sd’s are significantly different from each other, larger sd on top, if Fcalc > Ftable null hypothesis can be rejected

Question 24

F test formula

Answer 24

Fcalc=S1^2/S2^2

Question 25

confidence interval

Answer 25

we are 95% confident the true mean lies within the confidence interval, mu formula

Question 26

Q test

Answer 26

at least 3 data points, =|outlier-nearest neighbor|/|lowest-highest|, if Qcalc>Qcritical point can be discarded

Question 27

grubbs test

Answer 27

=|outlier-mean|/sd, if Gcalc>Gcritical then point can be discarded

Question 28

t-test

Answer 28

decide if there is a statistically significant difference between two mean values, if ttable>tcalc results are statistically equivalent

Question 29

t calc formula

Answer 29

compares measure mean value and known mean value

Question 30

F-test

Answer 30

2 sets of measured mean and 2 sets of s, F calc= S1^2/S2^2

Question 31

standard solutions

Answer 31

contains known concentration of analyte

Question 32

blank solutions

Answer 32

contains everything but analyte of interest

Question 33

linear range

Answer 33

range over which response is proportional to concentration

Question 34

dynamic range

Answer 34

range over which response is measurable, but not necessarily linear

Question 35

limit of detection/quantitation

Answer 35

smallest amount of analyte that will give a detection

Question 36

method of least squares

Answer 36

used to draw best "straight line", distance above/below line= yi-(mx+b)

Question 37

standard state

Answer 37

reference point used to calculate its properties under different conditions

Question 38

gibbs free energy

Answer 38

G=-RTlnK

Question 39

polyprotic

Answer 39

acid/base that can donate/accept more than 1 proton

Question 40

activity

Answer 40

ax=[x]yx, y is activity coefficient how far system is from ideality