Ch 2 - The Numerical Side of Chem

Question 0

Measurement

Answer 0

Contains uncertainty (penny has a 2.0 cm diameter)

Question 1

Exact number

Answer 1

Exhibits no uncertainty (the number 7, the number of coins in your pocket right now)

Question 2

Obtaining an exact number

Answer 2

1) When an object is counted

2) From numbers in a defined relationship (1 ft = 12 inches)

Question 3

Precision

Answer 3

How close various sets of measurements are to one another. Requires multiple measurements that are usually reported as an average.

Question 4

Accuracy

Answer 4

How close a value is to the true value. Only requires one measurement.

Question 5

What is your goal when performing an experiment/collecting data?

Answer 5

The goal is to be precise and accurate.

Question 6

A measuring tool…

Answer 6

1) Is used to determine a quantity such as the length or mass if an abject
2) Provides numbers for measurement

Question 7

Measured numbers

Answer 7

Numbers for a measurement usually collected using some kind of measuring device

Question 8

A number is a significant figure if..

Answer 8

1) Not a zero (3.5 <– 2 sig figs)

Question 9

A zero is NOT a significant figure if it is…

Answer 9

1) At the beginning of a decimal number (0.0007 <– 2 sig figs)

Question 10

Trailing zeros

Answer 10

If NO decimal point is present, trailing zeros are not significant (120 <– 2 sig figs).

Question 11

Scientific notation

Answer 11

Accepted practice to unambiguously indicate uncertainty. Only shows sig figs. Written as a number (A), multiplied by 10 raised to an exponent (x).

Question 12

Rounding rules: Multiplication and division

Answer 12

Maintain the smallest number of significant figures in the original measurement.
(2 cm)(2.0 cm) = 4 cm

Question 13

Rounding rules: Addition and subtraction

Answer 13

Maintain the lowest number of decimal places from original measurements.
123 + 2.006 + 2.6 = 126.606= 127

Question 14

Base SI Units

Answer 14

1) Length–> meter –> m
2) Mass –> kilogram –> kg
3) Time –> second –> s
4) Temp –> kelvin –> K
5) Substance amount –> mole –> mol

Question 15

US Units vs Metric

Answer 15

1m = 39.37 in
1kg = 2.2046 lbs
1kg = 1000g 
1lb = 453.6g

Question 16

Mass

Answer 16

The measurement of quantity of matter

Question 17

Greek prefixes used with SI Units

Answer 17

Pico- (p) one-trillionth (10^-12)
Nano- (n) one-billionth (10^-9)
Micro- (u) one-millionth (10^-6)
Milli- (m) one-thousandth (10^-3)
Centi- (c) one-hundredth (10^-2)
Deci- (d) one-tenth (10^-1)
Kilo- (k) one thousand (10^3)
Mega- (M) one million (10^6)
Giga- (G) one billion (10^9)

Question 18

Pressure unit

Answer 18

Pascals (Pa)

Question 19

Temperature conversion

Answer 19

F=32+(9/5)C

C=5/9(F-32)

K=C+273.15

C=K-273.25

Question 20

Density

Answer 20

Compactness of matter
d=m/V
Unit: g/mL or g/cm^3

Question 21

Intensive property

Answer 21

A property that does not depend on the amount of material present

(Ex: density)

Question 22

Extensive property

Answer 22

A property that depends on the amount of material present

Ex: mass and volume