Exam 1 (Ch 1-4)

Question 1

observation

Answer 1

statement describing a natural phenomenon that humans sense

Question 2

fact

Answer 2

a valid observation about a natural phenomenon;
explained by reproducible experimental data

Question 3

hypothesis

Answer 3

an untested potential explanation for an observation

Question 4

theory

Answer 4

a potential explanation for an observation that has been repeatedly tested and verified

Question 5

law

Answer 5

a generalization that describes observations about natural phenomenon, but does not explain them

Question 6

quantitative measurement

Answer 6

measurement that results in a number

Question 7

qualitative measurement

Answer 7

measurement that does not result in a number

Question 8

classical method

Answer 8

analytical method that relies on chemical reactions to perform an anaylsis

Question 9

instrumental method

Answer 9

analytical method that depends on the measurement of a physical property of the analyte

Question 10

mass

Answer 10

not affected by buoyancy

Question 11

weight

Answer 11

affected by buoyancy

Question 12

formal concentration (F) = ____

Answer 12

formal concentration (F) = molarity (M)

Question 13

alcohol proof = ____

Answer 13

proof = 2 * vol %

Question 14

systematic error (determinate)

Answer 14

consistent, reproducible error that can be detected and corrected; effects sample mean;
errors that result from incorrect instrument calibration, contaminated reagents, or other experimental errors that cause the average of many trials to be skewed in one direction from the true value

Question 15

random error (indeterminate)

Answer 15

errors that result from small, uncontrollable variances in instrumentation and glassware measurements; has an equal chance of being positive or negative; effects standard deviation

Question 16

gross error

Answer 16

errors that result from mistakes or negligence on the part of the investigator; effects sample mean and standard deviation

Question 17

mean

Answer 17

a measure of accuracy

Question 18

standard deviation

Answer 18

a measure of precision

Question 19

population mean = __

Answer 19

population mean = µ

Question 20

sample mean = __

Answer 20

sample mean = X̄

Question 21

population standard deviation = __

Answer 21

population standard deviation = σ

Question 22

standard deviation = __

Answer 22

standard deviation = s

Question 23

normally distributed

Answer 23

1) mean occurs at central point of maximum frequency
2) symmetrical distribution of positive and negative deviations about the maximum
3) there is exponential decrease in frequency as magnitude of deviations increases

Question 24

Gaussian (normal) distribution

Answer 24

the bell-shaped curve obtained by plotting frequency versus deviation from the mean

Question 25

significant figures

Answer 25

all of the digits in a number that are known with certainty plus the first uncertain digit

Question 26

variance = __

Answer 26

variance = s^2

(standard deviation squared)

Question 27

z = __

Answer 27

z = (x - µ) / σ

z = (x - X̄) / s

Question 28

sig figs: addition / subtraction

Answer 28

go to least decimal places

Question 29

sig figs: multiplication / division

Answer 29

go to least sig figs

Question 30

sig figs: log x

Answer 30

of digits = # of decimal places

Question 31

sig figs: 10 ^ x

Answer 31

of decimal places = # of digits