chapter 1

Question 1

define chemistry

Answer 1

the science that seeks to understand the behavior of matter by studying atoms and molecules

Question 2

what system is used for units?

Answer 2

• Use the metric system

* Kelvin used for temp, 273K = 0 Celsius

Question 3

define mass

Answer 3

Mass is the quantity of matter (g)

Question 4

define weight

Answer 4

• Weight is the force of gravity (kg)

Question 5

how are mass and weight related?

Answer 5

• Weight is proportional to mass

Question 6

what are derived units?

Answer 6

• Derived Units are a combination of units

Question 7

is mass derived or fundamental? weight?

Answer 7

• Mass is fundamental

* Weight is derived

Question 8

what is volume?

Answer 8

Volume is a measure of space

Question 9

how many ml are in a cubic cm?

Answer 9

1 mL = 1cm^3

Question 10

how many L are equal to a cubic meter?

Answer 10

1000 L = 1 m^3

Question 11

how many ml are in a L?

Answer 11

1L = 1000 mL

Question 12

how many cubic cm are in a L?

Answer 12

1L = 1000cm^3

Question 13

what do extensive properties rely on?

Answer 13

Extensive = value depends on quantity

Question 14

what do intensive properties rely on?

Answer 14

value is independent of quantity of matter
• Used to identify type of matter
• Identical intensive properties = same material

Question 15

does density have derived units or fundamental? what is density?

Answer 15

derived
ratio of mass to volume (m/v)
• g/L (gas), g/cm^2 (solid), g/mL (liquid)

Question 16

what is percent composition?

Answer 16

alternate way to describe a mixture

Question 17

% by volume formula

Answer 17

volume of component A/ total vol of mixture X 100%

Question 18

% by mass formula

Answer 18

2. % mass - mass of component A/total mass of mixture X100%

Question 19

in a mixture what does A + B = ?

Answer 19

100%

Question 20

how are small numbers dealt with?

Answer 20

prefix multipliers (ie mg), scientific notation

Question 21

what is precision?

Answer 21

• Precision: how close replicated measurements are to one another (random error)
  
  • One way to quantify is to calculate the standard of deviation of replicated measurements (smaller = more accurate)

Question 22

what is accuracy?

Answer 22

• Accuracy is the agreement of a measured value with the true/accepted value (systematic error)

Question 23

describe use of sig figs. what digits are included?

Answer 23

• All measurements have an amount of uncertainty
• Sig figs include all digits (certain) including the first uncertain digit
• When publishing results we must report all data to the corrects sig figs
Thus # of sigfigs is an indication of the instruments finest graduation (ie sensitivity limit)

Question 24

what is the number of sig figs an indicator of?

Answer 24

the number of significant figures is understood
to be an indication of the instruments finest graduation
(i.e. its sensitivity limit).

Question 25

which digit is uncertain?

Answer 25

• In any measurement each digit we include is certain,
except the last, which is an estimate
• The number of sig figs indicates the precision of an
instrument

Question 26

how is measurement precision last digit assumed?

Answer 26

assumed to be ±1 in the last digit
• The more digits an instrument provides the higher the
precision
- this also means a measurement has a smaller range of
expected values

Question 27

rules for adding and subtracting

Answer 27

Addition and Subtraction: The answer has the
same number of decimal places as there are in the
measurement with the fewest decimal places

Question 28

rules for multiplying and dividing

Answer 28

Multiplication and Division: The answer contains
the same number of sig figs as there are in the
measurement with the fewest significant figures

Question 29

rules for mixed operations

Answer 29

Follow order of operations. Carry out the operations
within the brackets first; retain a few extra digits to
prevent rounding errors; round the final answer to the
correct number of significant figures

Question 30

what is an exact number?

Answer 30

A number whose value is known with complete certainty
is exact
• from counting individual objects
• from defined quantities
• Exact numbers have an unlimited number of significant
figures