Technical Science
Introduction to Chemistry
The Study of Matter
In this section you will…
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Define Chemistry
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Explore Length
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Compare Mass and Weight
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Explore Time
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Explore Thermal Energy
Define Chemistry
But, that definition brings up another
question. What is matter?
Matter is anything that has mass and takes
up space.
In other words, matter is the
stuff
(solids,
liquids, and gases) of which the world is
made.
The most basic definition of chemistry is:
Chemistry is the study of matter.
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Define Chemistry
To study matter, we first need to describe it.
The most accurate kind of descriptions are
measurements.
So, to study matter we first need to be able
to measure it.
Chemistry is the study of matter. Now you know
what matter is but what does it mean to study?
Define Chemistry
–
Distance
–
Time
–
Mass
–
Energy
These quantities are consider “basic”
because they can’t easily be broken down
into simpler units of measure.
There are four basic quantities of matter that
we can measure. They are…
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Explore Length
Length is the distance (or space) between two points.
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Length is a measurement of space.
Space is a fundamental property of the
universe therefore length is a fundamental
measurement.
In order to determine distance or size we
Explore Length
You are probably familiar with some units for
measuring length.
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In the English Measurement System some units of
length are…
Inches 1 inch
Feet
Yards
Miles
12 inches = 1 foot
3 feet = 1 yard
Explore Length
In the Metric System the base unit of length is the
Meter. Prefixes identify additional units of length.
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Each unit is separated from the next larger or
smaller by a factor of ten.
meter
dekameter = 10 meters
hectometer = 100 meters or 10 dekameters kilometer = 1000 meters or 10 hectometers
decimeter = 0.1 meters
kilometer hectometer dekameter meter decimeter centimeter millimeter Converting within the Metric System is
a two-step process
Explore Length
It is important to be able to convert from one unit
of measure to another.
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Convert: 1543 meters = _________ kilometers
Step 1: Count the number of places separating the two units. This will be the number of
places you move the decimal point.
Move 3 Places Step 2: Move the decimal the
appropriate direction. To convert to a larger unit, move the decimal to the left.
(You will need fewer large units so the number you start with must get smaller.)
To The Left
Explore Length
Convert these metric lengths then click to see the
answers. Review “The Metric System” tutorial if
you are having trouble converting metric measures
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278 cm = ________m 0.0076 km = ________m
19 mm = ________cm 250 m = _________km
0.075 m = ________mm 39.1 cm = ________mm
2.78 7.6
1.9 0.25
Explore Length
Use the Conversion Factor Method to convert
English measurements of length.
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4 ft
1 x 1 ft 12 in
= 48 inches
Initial Measure
Conversion
Factor Converted Measure
Convert: 4 feet = _________ inches
Step 1: Record your initial measurement in the form of a fraction
Step 2: Identify conversion factors. You want to convert from feet to inches so an appropriate conversion factor would be…
1 foot 12 inches
Step 3: Multiply your initial measurement by the conversion factor so the units you want to eliminate cancel out.
Step 4: Perform the calculation. Start
with the initial measurement. Multiply by any number that shows up on top and
divide by any number that shows up on the bottom. (4 x 12 = 48)
48
This method can be used to convert between the English and Metric systems
Explore Length
Use the conversion factor method to make the
following conversions then click to see the
answers.
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30.0 cm = ________ft 0.01 yd = ________cm
1.90 yd = ________in 0.331 m = _________in
0.012 in = ________mm 9850 in = ________mi
0.98 0.9
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Compare Mass and Weight
Chemistry is the study of matter.
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Matter is defined as anything that has mass and
takes up space.
We found that describing space begins with
measuring length.
In the same way, describing matter begins with
measuring mass.
Mass is a measurement of how much matter is
present.
Compare Mass and Weight
In the Metric System the base unit of Mass is the
Gram. Prefixes identify additional units of Mass.
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Each unit is separated from the next larger or
smaller by a factor of ten.
gram
dekagram = 10 grams
hectogram = 100 grams or 10 dekagrams kilogram = 1000 grams or 10 hectograms
decigram = 0.1 grams
kilogram hectogram dekagram gram decigram centigram milligram Converting within the Metric System is
a two-step process
Compare Mass and Weight
It is important to be able to convert from one unit
of measure to another.
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Convert: 0.125 grams = _________ milligrams
Step 1: Count the number of places separating the two units. This will be the number of
places you move the decimal point.
Move 3 Places
Step 2: Move the decimal the appropriate direction. To convert to a smaller unit, move the decimal to the Right.
(You will need more small units so the number you start with must get larger.)
To The Right
Compare Mass and Weight
Convert these metric masses then click to see the
answers. Review “The Metric System” tutorial if
you are having trouble converting metric measures
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30.9 kg = ________g 0.00089 kg = ________mg
62 mg = ________g 710 g = _________kg
0.0048 g = ________mg 8.2 kg = ________g
30900 890
0.062 0.71
Compare Mass and Weight
Metric units of mass include grams, kilograms,
milligrams, etc.
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What are the units of mass in the English System?
If you said pounds or ounces, you were mistaken.
The English unit of mass is the slug.
Pounds and ounces are measurements of
weight
not mass.
Although we use the terms mass and weight
Compare Mass and Weight
Mass vs Weight.
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Let’s look at the devices used to measure mass and
weight and see if we can discover the difference.
Mass is measured with a device called a balance
Balance
The object to be measured is placed in one pan. The other pan is loaded with mass units until the two pans balance
? 10 g
5 g
When the pans balance you know you have the same amount of matter on each side. In this case, the mass of the object is 15 grams
So, Mass is a measure of
Compare Mass and Weight
Mass vs Weight.
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Let’s look at the devices used to measure mass and
weight and see if we can discover the difference.
Weight is measured with a device called a scale.
Scale
The object to be measured is placed on the platform. The weight of the object pushes the platform down which moves the arrow along the scale.
?
One thing that determines the
reading on the scale is the amount of stuff we put on the platform. In other words, weight is
determined in part by mass.
? 10 g
5 g
Compare Mass and Weight
Mass vs Weight.
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To find the other component of weight we need to
take a trip to the moon.
Weight is determined by
mass and the pull of gravity
?
What would happen if we put our balance on the moon? Would it still be balanced?
If it was balanced on Earth then it will remain balanced on the Moon because there is still the same
amount of matter in each pan.
What would happen if we put the scale on the moon? Would we still get the same value for the weight? (Remember the mass hasn’t changed) The reading on the scale would be different because gravity is different from the Moon to Earth. Weight is a measure not only of the mass but also how hard gravity pulls on the mass.
The pull of gravity is less on the Moon therefore the weight of the object is less on the Moon than it is on Earth. Mass stayed the same because it is just a
Compare Mass and Weight
What is the difference between Mass and Weight?
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Mass is a measurement of the amount of matter in
an object. In other words, mass is the amount of
“stuff”.
Weight is a measure of the amount of matter and
Compare Mass and Weight
Since Mass and Weight are different quantities, it
follows that they will use different units of
measure.
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Complete the table below with the proper units of
measure then click to see the answers.
Mass
Weight
Metric
English
gram, kg, mg
slug
newton
Compare Mass and Weight
What is the mass of 5000 kg spacecraft on the
moon. Gravity on the Moon is 1/6 that of Earth.
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5000 kg. Kilograms are a measure of mass and
mass does not change.
A spacecraft on earth weighs 30,000 lb. What is the
weight of the spacecraft on Pluto. Gravity on Pluto
is 1/15 that of Earth.
2000 lb. Pounds are a measurement of weight and
weight changes depending on gravity.
Explore Time
Time is another fundamental property of the
world.
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The amount of time that elapses that during
the course of an event is called the duration.
The amount of time that separates two
events is called the interval.
The ability to measure intervals and
Explore Time
You are already very familiar with the units used
to measure time.
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The base unit of time is the second
Second
The units that we use to measure time are rather interesting because we use a combination of
English and Metric units For units of time larger than a second we tend to use English units.
Minute Hour Day
Year For units of time smaller
than a second we tend to use Metric units.
millisecond microsecond nanosecond
= 60 seconds = 60 minutes = 24 hours = 365 days
= 0.001 seconds
= 0.000001 seconds
Explore Time
Convert these units of time then click to see the
answers. Use the conversion factor method for the
English conversions.
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0.75 hour = ________sec 0.0041 sec = _______msec
62 msec = ________sec 590 sec = _________min
0.25 year = ________hours 10 min = ________hours
2700 4.1
0.062 9.8
2190 0.17
Explore Thermal Energy
The final fundamental property is energy.
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Energy is the ability to do work.
In other words, nothing can be made, or
moved, or accomplished without energy.
Energy can take on many forms but the one
we will study in this section is the form of
energy that is contained in all matter.
Explore Thermal Energy
All matter has thermal energy because the particles that make up matter are
constantly moving.
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It isn’t hard to imagine that the particles of a
liquid or a gas are moving.
Explore Thermal Energy
But what about a solid object like a pencil?
Solids certainly don’t seem to be moving.
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The pencil itself may not be moving, but the
Explore Thermal Energy
All objects have thermal energy (heat)
because their particles are moving.
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The hotter an object gets the faster the particles move
Explore Thermal Energy
As an object gets colder the particles slow
down. What would happen if all of the heat
is removed from an object?
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If all the heat is removed from an
object, the particles would stop
moving completely.
Explore Thermal Energy
Thermal energy is the result of the collisions
of the particles of a substance.
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This works the same way as when you rub
your hands together to warm them up.
Thermal energy however is not the same
Explore Thermal Energy
An object’s thermal energy or heat is
determined by the sum of the energies of all
the particles is a substance.
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Temperature is a measurement of the
average energy of the particles in substance.
The following example will better explain
Explore Thermal Energy
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Let’s heat up a large and small container of water on a hot plate until both containers begin to boil Now let’s record the temperatures of the water in each container.
100° C 100° C
Water boils at 100°C. Since both containers are boiling both containers have the same temperature. The water particles in each container have the
same average energy.
Which container do you think has more thermal energy (heat)?
Less Heat
More Heat
Heat is the sum of the energies of all the particles in a substance. Since there are more water particles in the large container there is more heat as well.
Make Temperature
Conversions
Temperature is a measurement of the
average energy of the particles in substance.
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Temperature is measured on a scale called
a thermometer.
There are three different temperature scales
currently used to measure temperature.
Fahrenheit, Centigrade, and Kelvin
Make Temperature
Conversions
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Fahrenheit Centigrade
Kelvin
On the Fahrenheit scale, zero is the freezing point of saturated salt water.
A temperature scale must
have a point to call zero.
0° F
On the Centigrade scale, zero is the freezing point
of pure water. 0° C
On the Kelvin scale, zero is the point where there is no heat: Absolute Zero
0 K
One difference between the
Make Temperature
Conversions
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Fahrenheit Centigrade
Kelvin
The first temperature is the freezing point of pure water
Record two temperatures.
32° F
Water Freezes 273 K 0° C
The second temperature is the boiling point of pure water
212° F 100° C
373 K
Water Boils
How many degrees of change is it from freezing to boiling on each scale?
100 100 180
Freezing to boiling on the K and C scales both represent 100 degrees of change.
This means that the degrees on the Kelvin and Centigrade scales are the same size.
Freezing to boiling on the Fahrenheit scale represents 180 degrees of change.
This means that Fahrenheit degrees are smaller than
Kelvin and Centigrade degrees Compare 100 to 180.
100 = 10 = 5 180 18 9
Make Temperature
Conversions
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If the temperature goes up 3° on the Centigrade
scale, how far does it rise on the Kelvin scale?
Fahrenheit Centigrade
Kelvin
32° F Water
Freezes 273 K 0° C
212° F 100° C
373 K Water Boils
100 100 180
B.) 3°
Centigrade degrees are the same size as Kelvin degrees
.
A.) More than 3° B.) 3°
Make Temperature
Conversions
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If the temperature goes up 3° on the Fahrenheit
scale, how far does it rise on the Centigrade scale?
Fahrenheit Centigrade
Kelvin
32° F Water
Freezes 273 K 0° C
212° F 100° C
373 K Water Boils
100 100 180
C.) Less than 3°
Centigrade degrees are larger than Fahrenheit degrees
A.) More than 3° B.) 3°
Make Temperature
Conversions
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Now that you understand the differences between the three temperature scales we will make some temperature
conversions.
The formulas are listed below. Copy them
down so you can refer to them.
K = C + 273
C = K - 273
C = 5/9( F – 32 )
Make Temperature
Conversions
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The first thing you need to do is choose the
proper formula.
The formula,
K = C + 273
,is solved for K.
K is by itself on one side of the equals sign.
This formula will calculate Kelvin when you
know the temperature in Centigrade.
Choose a formula that is solved for the
Make Temperature
Conversions
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In each case below, decide which formula
you will use then click for the answers.
K = C + 273
C = K - 273
C = 5/9(F – 32)
F = 9/5 C + 32
Given Fahrenheit calculate Centigrade
Calculate Kelvin given Centigrade
Calculate Fahrenheit given Centigrade
Make Temperature
Conversions
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Next, you must perform the mathematical
operations in the correct order.
When you solve a formula you must follow
Orders of Operations. (shown below)
First Parentheses ( ) Second
Third Multiplication X & Division ÷ Fourth Addition + & Subtraction
Make Temperature
Conversions
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What is the order of mathematical operations
indicated by the following formulas.
K = C + 273
C = K - 273
C = 5/9(F – 32)
F = 9/5 C + 32
One operation + Add C + 273
One operation
-
Subtract K - 273First ( ) Subtract F – 32
First X Multiply 9/5 x C
Second X Multiply 5/9 x 1st step
Make Temperature
Conversions
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Centigrade Kelvin
Water Freezes 273 K 0° C 100° C 373 K
Water Boils
100 100
Convert between Kelvin and Centigrade
K = C + 273 C = K - 273
320 K = _____°C
C = K - 273
C = 320 – 273
C = 47 °
47 16 °C = _____K
K = C + 273
K = 16 + 273
K = 289
289
K and C degrees are the same size, so all we have to do is account for the different
Make Temperature
Conversions
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Fahrenheit Centigrade
32° F Water Freezes 0° C
212° F 100° C
Water Boils
100 180
Convert between Fahrenheit and Centigrade
C = 5/9(F – 32) F = 9/5 C + 32
F and C degrees are different size, we
account for this by multiplying by 5/9 or 9/5.
The Fahrenheit and Centigrade scales have a different starting point so we have to
account for this by adding or subtracting 32.
81° F = _____°C
C = 5/9(F – 32)
C = 5/9(81 – 32)
C = 5/9(49)
C = 27 °
27 93° C = _____°F
F = 9/5 C + 32
F = 9/5 (93) + 32
F = 167 + 32
F = 199 °
Make Temperature
Conversions
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Make the following temperature conversions then
click to see the answers.
C = 5/9(F – 32) F = 9/5 C + 32 K = C + 273 C = K - 273
400 K = ______°C 15° F = ______°C
- 5° C = ______°F 50° C = ______K
240 K = ______°C 300° F = ______°C
- 25° C = ______°F - 8 ° C = ______K
127 - 9.4
23 323
- 33 149
- 13 265
