chapter 1 matter and energy. what is chemistry chemistry is the study of matter and its changes

Chapter 1Matter and Energy

What is Chemistry

Chemistry is the study of matter and its changes

What is Matter?

Matter is anything that occupies space and has weight.

Examples of Matter

• Pens and pencils

• Paper

• Students

• Desks

• Cars

• Airplanes

Is Air Matter?

Air would be matter if it takes up space and has weight.

Is Air Matter?


Does it?

Is Air Matter?


Does it?

The space that air takes up is called the atmosphere.

Does air have weight?

Is Air Matter?


Does it?

The space that air takes up is called the atmosphere.

Does air have weight?

Yes air does have weight, if not, then it would flow into outer space.

Is Air Matter?

Air would be matter if it takes up space and has weight.Does it?The space that air takes up is called the atmosphere.Does air have weight?Yes air does have weight, if not, then it would flow into outer space. One liter of air weighs 1.29 grams.

What are Changes?In the study of chemistry we talk about two different kinds of changes, physical and chemical


Physical change is a change to matter so that the identity is not altered; i.e. taste, smell….


Physical change is a change to matter so that the identity is not altered; i.e. taste, smell….

Chemical change is a change to matter so that its identity is changed; i.e. different smell, color, taste.

Examples of Physical Change

• Tearing paper; starts out paper and ends as paper

• Folding paper ; starts out paper and ends as paper

• Melting of ice ; starts out water and ends as water

• Evaporation of water ; starts out water and ends as water

Examples of Chemical Change• Wood burning; starts out as wood ends up

as smoke and ashes, different smell and taste, right?

• Steel rusting; starts out as steel ends up as rust, different smell and taste

• Healing of a wound; starts out a blood ends up as scar tissue, different color, taste and smell

Matter Continued

Is everything matter?

Matter Continued

Is everything matter? No, not everything we can think of has weight and takes up space.

Matter Continued


For example personality!

Matter Continued


For example personality! One might argue that personality takes up the space of ones brain or person, but…

Matter Continued


For example personality! One might argue that personality takes up the space of ones brain or person, but…not all personable people are overweight. Thus personality does not have weight, and is therefore not matter.

Matter ContinuedHow about thought? Again we might argue that thought takes up the space of ones brain and your mother told you about heavy thoughts, but….

Matter ContinuedHow about thought? Again we might argue that thought takes up the space of ones brain and your mother told you about heavy thoughts, but….If you get on the bathroom scale and start having heavy thoughts, your weight does not go up!

Matter ContinuedHow about thought? Again we might argue that thought takes up the space of ones brain and your mother told you about heavy thoughts, but….If you get on the bathroom scale and start having heavy thoughts, your weight does not go up! That means thought is not matter, so if someone studies thought, they are not doing chemistry.

Examples of Chemistry• The study of why wood burns

• The study of why cement does not burn

• The study of why nails rust

• The study of milk spoiling

These all fit the definition of chemistry since they deal with change and matter

History of Chemistry

Who were the first chemists?

History of ChemistryWho were the first chemists?

History of ChemistryWho were the first chemists?

Cavemen

History of ChemistryWhat kind of matter and changes did the cavemen study?

History of ChemistryWhat kind of matter and changes did the cavemen study? Fire and food!

Archeologists have found evidence of fire in caves and animal bones too. Cooking meat makes meat chewable. Chewing raw meet wears out ones jaw.

History of ChemistryThe next group that left archeological evidence of chemistry were the Egyptians. Their chemistry involved mummies, textile dyes, ink, paper and paints most of which can be found inside the pyramids.

History of ChemistryThe first group of people to leave written records of their chemistry were the Greeks. From Greek writings, we can see that the Greeks made observations, and created reasons for these observations, called hypothesis. They did not attempt to prove their hypothesis by experimentation, thus their chemistry efforts were philosophical in nature as opposed to science in nature.

History of ChemistryThe first group of chemists to test hypothesis with experiments were the alchemists. Alchemists were a group of Europeans that were trying to change matter in to different kinds of matter. For example, they were trying to change lead into gold. The major results of their experiments were to prove most of the Greek ideas of chemistry to be false and to show a clear distinction between science and philosophy.

History of Chemistry

A major short coming of the Alchemists chemistry was irreproducible results, caused by lack of measurement understanding. For example, on day 1 mixing two kinds of matter produced black matter, while doing the same thing the next day produced red matter. The Alchemists were the first group of chemists to make observations, create hypothesis, and to test their hypothesis with experiments.

Modern Chemistry

Antoine Lavoisier was the founder of modern chemistry by making careful measurements.

Modern ChemistryLavoisier’s careful measurements now made experiments reproducible. Chemists in other countries could now do the same experiment and get the same results. This now allowed chemists to prove a hypothesis to be correct by experimentation, thus leading to the discovery of theories and laws.

Modern Chemistry

• Law of Conservation of Mass

• Atomic Theory

Lavoisier’s Theories and Laws

Scientific MethodIs a sequence of thoughts and

experiments containing the following:

• A hypothesis is a tentative and testable explanation for an observation or a series of observations.

• A scientific theory is a general explanation of widely observed phenomena that have been extensively tested.

Classification of Matter

Matter

Homogeneous Heterogeneous

SolutionsSubstances

Elements Compounds


Homogeneous matter looks the same everywhere with a microscope, but since we lack microscopes we will use our eyes and not our imagination. Heterogeneous matter does not look the same everywhere.

Homogeneous and Heterogeneous

Classification of MatterHomogeneous or Heterogeneous?

Wood Carpet Margarine Gold


Wood Carpet Margarine GoldHeterogeneous


Wood Carpet Margarine GoldHeterogeneous Heterogeneous


Wood Carpet Margarine GoldHeterogeneous Heterogeneous Homogeneous


Wood Carpet Margarine GoldHeterogeneous Heterogeneous Homogeneous Homogeneous

Classification of MatterSolution is a homogeneous random combination of two or more different types of matter.

For example a random amount of salt and water combined together produces a homogeneous mixture, called salt water. Random combination means some salt and some water.

Classification of MatterAny combination the produces a homogeneous result that is not randomly created is called a substance.

For example, combining two hydrogen atoms and one oxygen atom produces a compound of water, which is a substance. Or the combination of two oxygen atoms, gives a molecule of oxygen.


Homogeneous matter created by the same atom is called and element. Exact combinations of different elements is called a compound.

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand•Sea water•Tap water•Steel•Antimony•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water•Tap water•Steel•Antimony•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water•Steel•Antimony•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel•Antimony•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony-Element•Air•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony-Element•Air-Solution•Distilled water•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony-Element•Air-Solution•Distilled water-Compound•Cement•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony-Element•Air-Solution•Distilled water-Compound•Cement-Heterogeneous•Wine

Classification of MatterLabel the following examples of matter as heterogeneous, solution, compound or element.•Sand-Heterogeneous•Sea water-Heterogeneous•Tap water-Solution•Steel-Solution•Antimony-Element•Air-Solution•Distilled water-Compound•Cement-Heterogeneous•Wine-Solution

Classification of Matter• Types of Matter

1. Pure Substances have the same physical and chemical properties throughout.

2. Mixtures are composed of two or more substances (elements or compounds) in variable proportions.

Elements and Compounds• Most elements are not found in the world in

the pure form. They are found in compounds.

• Hydrogen is found in water, H2O, and other hydrogen containing compounds.

• The law of constant composition states that every sample of a compound always contains the same elements in the same proportions.

Pure Substances• Two Groups

1. An element is the simplest kind of material with unique physical and chemical properties.

2. A compound is a substance that consists of two or more elements linked together in definite proportions.

An Atomic View• An atom is the smallest particle of an element

that retains the chemical characteristics of that element.

• A molecule is a collection of atoms chemically bonded together having constant proportions.

Chemical Formulas• Chemical bonds link

atoms together to make molecules.

• Chemical formulas use symbols to represent atoms with subscripts to identify the number of each atom present.

Chemical Reactions• Chemical reactions show

the transformation of one or more substance into different substances.

• Chemical equations use chemical formulas to express the identities and quantities of substances involved in a reaction

Separating Mixtures

• No chemical reactions are needed to isolate the constituents in a mixture.

Filtration

Distillation

Filtration

Distillation

Properties of Matter• Intensive property - a characteristic that is

independent of the amount of substance present.Examples: color, hardness, etc.

• Extensive property - a characteristic that varies with the quantity of the substance present.Examples: length, width, mass, etc.

State of Matter• Solids have definite shapes and

volumes.

• Liquids occupy definite volumes, but do not have definite shapes.

• Gases have neither a definite shape nor volume.

• Plasma, not found on earth, but stars, similar to a gas, but a mixture of subatomic particles

Examples

Making Measurements• Accurate measurements are essential

for our ability to characterize the physical and chemical properties of matter.

• Standardization of the units of measurements is essential.

Some Prefixes for SI Units

Prefixes Value

Name Symbol Exponential

Mega M 106

Kilo k 103

Hecto h 102

Deka da 10

Deci d 10-1

Centi c 10-2

Milli m 10-3

Micro 10-6

Nano n 10-9

Pico p 10-12

Memorize the ones in blue

SI Base Units

Quantity Unit NameUnit

Abbreviation

Mass Kilogram kg

Length Meter m

Temperature Kelvin K

Time Second s

Energy Joule J

Electrical Current Ampere A

Amount of Substance

Mole mol

Luminosity Candela cd

English Metric Conversions

• 1 in = 2.54 cm Length

• 1 lb = 453.6 g Mass

• 1qt = 946.4 mL Volume

These are definitions, thus lacking significant figures

Scientific Measurements • A measurement always has some

degree of uncertainty due to the fact that measuring devices have scales. A digit that must be estimated is called uncertain due to the fact that it is between the scale lines, or appears to be on a scale line.

Counting Significant Figures• All numbers counted in a measurement are All numbers counted in a measurement are

significant.significant.• Zero’s sandwiched by two numbers are Zero’s sandwiched by two numbers are

counted.counted.• If a zero is used to locate a decimal, then it If a zero is used to locate a decimal, then it

is not a number, but a spacer and is not is not a number, but a spacer and is not counted.counted.

• Additional information sometimes is Additional information sometimes is available the make zeros both numbers and available the make zeros both numbers and decimal spacers.decimal spacers.

Practice How many significant figures are in the How many significant figures are in the

following numbers?following numbers?

0.04550 g

100 lb

101.05 mL

350.0 g



0.04550 g 4 significant figures

100 lb

101.05 mL

350.0 g




100 lb 1 significant figure

101.05 mL

350.0 g





101.05 mL 5 significant figures

350.0 g





101.05 mL 5 significant figures


Counting Significant Figures• Exact numbers Exact numbers have an infinite have an infinite

number of significant figures.number of significant figures.• Exact numbers Exact numbers are either counted are either counted

or defined.or defined.

• 1 inch = 2.541 inch = 2.54 cm, exactlycm, exactly

Rounding Rules• Addition and Subtraction: Round Addition and Subtraction: Round

answer so that it contains the same answer so that it contains the same number of number of decimal places decimal places as the as the measurement with the lease measurement with the lease number of number of decimal placesdecimal places..

• 6.8 + 11.934 = 18.734 6.8 + 11.934 = 18.734 18.7 (1 18.7 (1

decimal place)decimal place)

Rounding Rules

• Multiplication and Division: Round Multiplication and Division: Round answer so that it contains the same answer so that it contains the same number of number of significant figures significant figures as the as the measurement with the least number of measurement with the least number of significant figuressignificant figures..

• 6.38 6.38 2.0 = 12.76 2.0 = 12.76 13 (2 sig figs) 13 (2 sig figs)

Precision and Accuracy

Precision is how close measurements are to each otherAccuracy is how close a measurement is to the true value.

There have been many serious incidents that have resulted from

errors in converting between systems of units.

Air Canada Flight 143

(Google it for more details)

Unit Conversion Accidents

$125 million Mars Climate Orbiter.

Lost in Space.

Dp you think there is the potential to make errors in the

conversion of units for health care providers?

Unit Conversion Accidents

Conversion Problem Steps

1. Write down the number and unit.2. Draw lines; a vertical line after the number an

unit and horizontal line below the number and unit.

3. Insert a fractional fact to cancel out the original unit.

4. Compare the new unit to the asked for unita. If the same, you are done.

b. If not the same, repeat step 3.

Sample Conversion Problems

1. How many grams are in 47.2 mg? 2. Change 702 cL to µL.

Step 1. Write down the number and unit.

47.2 mg




47.2 mg

Step 2. Draw lines

47.2 mg




47.2 mg

Step 2. Draw lines

47.2 mg

Step 3. Insert fractional fact crossing out original unit




47.2 mg

Step 2. Draw lines

47.2 mg


47.2 mgmg10-3 g




47.2 mg

Step 2. Draw lines

47.2 mg


47.2 mgmg10-3 g

Step 4. Compare new unit to the asked for unit.




47.2 mg

Step 2. Draw lines

47.2 mg


47.2 mgmg10-3 g

Step 4. Compare new unit to the asked for unit.A. If the same you are doneb. If not the same repeat step 3.




47.2 mg

Step 2. Draw lines

47.2 mg


47.2 mgmg10-3 g


= 0.0472 g




702 cL

Step 2. Draw lines

702 cL


702 cLcL10-2 L





702 cL

Step 2. Draw lines

702 cL


702 cLcL10-2 L


Not a match repeat step #3




702 cL

Step 2. Draw lines

702 cL


702 cLcL10-2 L


10-6 L

μL

It’s a match, done




702 cL

Step 2. Draw lines

702 cL


702 cLcL10-2 L


10-6 L

μL

It’s a match, done

= 7.02 x 106 μL

DENSITY• What is heavier 5 pounds of lead or 5

pounds of feathers?

• What takes up more space, 5 pounds of lead or 5 pounds of feathers?

DENSITY

• What is heavier 5 pounds of lead or 5 pounds of feathers? Both the same. This is an old riddle to confuse density with weight

• What takes up more space, 5 pounds of lead or 5 pounds of feathers?

DENSITY

• What is heavier 5 pounds of lead or 5 pounds of feathers? Both the same. This is an old riddle to confuse density with weight

• What takes up more space, 5 pounds of lead or 5 pounds of feathers? Feathers, since they are less dense.

We can determine the volume of irregularly shaped objects by displacement.

How can we determine the volume of a gas?Gases fill whatever container they are placed in. So it’s the volume of the container !

Archimedes Principle

DENSITY UNITS

g/ml, g/cm3, (for solids and liquids), or g/L for gases

MATTER AND ENERGYThe End

chapter 1 matter and energy. what is chemistry chemistry is the study of matter and its changes

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