Chemistry 131 -- ch1

chemistry

the study of the composition, structure, properties, and reactions of matter

chemical

any material used in or produced by a chemical process

scientific method

1. observation
2. hypothesis
3. experiments
4. reporting
5. theory

metric units of measure

lenght - meter (m)
volume - liter (L)
mass - gram (g)
time - second (s)
temperature - celsius (C)

SI units of measure

length - meter (m)
volume - cubic meter (cm3)
mass - kilogram (kg)
time - seconds (s)
temperature - kelvin (K)

meter = ___inches

39.4 inches

1 inch = ___cm

2.54 cm

volume

the amount of space a substance occupies

1 liter = ___qt

1.06 qt

1 qt = ___ml

946 ml

mass

the measure of the quantity of material an object contains
*does not depend on gravity, so units of mass should not be used to refer to weight

weight

measure of the gravitational pull on an object

the gravitational pull on the moon is __/__ of the gravitational pull on the earth

1/6

1 kg = ___lbs

2.20 lbs

1 lb = ___ g

454 g

temperature

measure of how hot or cold an object is

celsius:
1. water boil
2. water freeze

1. 100 C
2. 0 C

Fahrenheit:
1. water boil
2. water freeze

1. 212 F
2. 32 F

scientific notation

number written in two parts: 1) coefficient 2) power of ten
*coefficient is number between 1-10

scientific notation:
for a number greater than 1 the power of ten is ___

positive

scientific notation:
for a number that is less than 1 the power of ten is ___

negative

if power of ten is positive, then you know it is a number __

greater than 1

if the power of ten is negative, then you know it is a number ___

less than 1

how many zeros in 10 to 4th power?
how many zeros in 10 to negative 4th power?

1. 4 zeros (10,000)
2. 3 zeros (0.0001)

measured numbers

numbers obtained by measuring device

what is meant by "uncertainty" in measuring

1. there is always uncertainty in measurements
2. the last number written is always the "estimated" number

significant figures

all the digits including the estimated digit (all non-zero & some zeros)

what are the 4 rules for determining that a figure is significant

1. not a zero
2. a zero between non-zero digits
3. a zero at the end of a decimal number
4. any digit in the coefficient of a number written in scientific notation

what are the 2 rules for determining that a number is not significant

1. zeros at the beginning of a decimal
2. used as a place holder in a large number without a decimal point

exact numbers

1. numbers obtained by counting items
2. definition that compares two units in the same measuring system

1 qt = ___ cups

4 cups

1 lb = ___ oz

16 ounces

how do you determine number of significant figures in multiplication and division

the final answer is written so it has the same number of significant figures as the measurement with the fewest significant figures

how do you determine the number of significant figures in addition and subtraction

the final answer is written so it has the same number of decimal places as the measurement with the fewest decimal places

prefix:
billion

giga
G
10 to 9th power

prefix:
million

mega
M
10 to 6th power

prefix:
thousand

kilo
k
10 to the 3rd

prefix:
one tenth

deci
d
10 to -1 power

prefix:
one-hundreth

centi
c
10 to -2 power

prefix:
one-thousandth

milli
m
10 to -3 power

prefix:
one-millionth

micro
u
10 to -6 power

prefix:
one-billionth

nano
n
10 to -9 power

equalities

1. show the relationship between two units that measure the same quantity (ex: 1m = 100cm)
2. has both a number and a unit

1 mL has what 2 equalities

1mL = 1cc = 1cm3

conversion factor

1. an equality written in the form of a fraction
2. one quality is the numerator & the other is the denominator

1 gallon = ___ qts

4 qts

1 qt = ___ pints

2 pints

when an equality shows the relationship of units from two different systems, the number is _____

measured and counts toward significant figures

what equality which shows the relationship between two different systems, is an exception, and has been deemed "exact"

1 in = 2.54 cm

when an equality shows the relationship for two units from the same system, it is considered ____

a definition, and "exact"
*does not contribute to determination of significant figures

in terms of conversion factors stated in word problems, when we see "per" what should we think

per means divided by
*ex: 100 mph = 100miles / 1 hour

what do we do with a % in a story problem

the % is parts of 100, so we simply place %/100
*because this is %/100, different units can be used as long as they reflect the same %/100 ratio

what are the steps in solving a problem using conversion factors

1. state the given and needed units
2. write a unit plan to convert the given unit to the final unit
3. state the inequalities and conversion factors to cancel units
4. set up problem to cancel units and solve problem

density

1. comparison of the mass of an object to its volume
2. Density = mass / volume

how do we determine the density of a solid

1. mass/volume
2. when a solid is completely submerged, it displaces a volume of water that is equal to its own volume

specific gravity (sp gr)

1. is a ratio between the density of a substance and the density of water
2. sp gr = density sample / density water
3. term to compensate for fact that density is affected by temperature

what is the density of water

1.00 g/mL

1 tsp = ___mL

5.0 mL

1mL = ___ g

1.20 grams

what is density dependant on

temperature

T or F:
density and sp gr are the same at room temp

T

in terms of density and sp gr, which have units

density has units; sp gr does not

how does heat flow relative to two objects of differing temperatures

heat always flows from a substance that is higher in temperature to a substance that is lower in temperature until the termperatures of both are the same

what is the formlula for converting celsius to fahrenheit

Tf = 1.8(Tc) + 32

what is the formula for converting fahrenheit to celsius

Tc = Tf - 32 / 1.8

how do we calculate a kelvin temperature

add 273 to the celsius temperature