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UNIT 1 – Introduction: Matter & Measurement

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What chemists try to do is discover the relationships between the particle structure of matter and the properties of matter we observe.

Chemistry is the science that seeks to understand what matter does by studying what atoms and molecules do.

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Everything is made of tiny pieces called atoms and molecules.

Chemists believe that the properties of a substance are determined by the kinds, numbers, and relationships between these pieces.

The Greeks believed in four basic elements: earth, air, fire, and water.

All substances were combinations of these four basic elements.

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Most other sciences demand an understanding of basic chemical principles, and chemistry is often referred to as the “central science.”

Study of composition, structure, properties, and reactions of matter.

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Chemistry is a science that studies the composition of matter and its properties.

Chemistry is divided into several branches: Organic chemistry is the study of substances

containing carbon. Inorganic chemistry is the study of all other

substances that don’t contain carbon. Biochemistry is the study of substances

derived from plants and animals.

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Knowledge of chemistry is important to understanding the world around us.

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Employment Opportunities Chemical lab technicians Biological lab technicians Validation and documentation technicians Quality control technicians Analytical technicians Biochemistry technicians Chemical analysts Formulation technicians Laboratory technicians Pilot plant technicians Chemical laboratory assistants

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Potential Employers Federal and provincial governments Food product companies Pharmaceutical companies Chemical product manufactures Industrial chemical manufactures Environmental laboratories Scientific companies Municipal laboratories Private laboratories

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Matter is any substance that has mass and occupies volume.

Matter exists in one of three physical states: solid

liquid

gas

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In a gas, the particles of matter are far apart and uniformly distributed throughout the container.

Gases have an indefinite shape and assume the shape of their container.

Gases can be compressed and have an indefinite volume.

Gases have the most energy of the three states of matter.

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In a liquid, the particles of matter are loosely packed and are free to move past one another.

Liquids have an indefinite shape and assume the shape of their container.

Liquids cannot be compressed and have a definite volume.

Liquids have less energy than gases but more energy than solids.

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In a solid, the particles of matter are tightly packed together.

Solids have a definite, fixed shape.

Solids cannot be compressed and have a definite volume.

Solids have the least energy of the three states of matter.

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Most substances can exist as either a solid, liquid, or gas.

Water exists as a solid below 0 °C; as a liquid between 0 °C and 100 °C; and as a gas above 100 °C.

A substance can change physical states as the temperature changes.

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When a solid changes to a liquid, the phase change is called melting.

A substance melts as the temperature increases.

When a liquid changes to a solid, the phase change is called freezing.

A substance freezes as the temperature decreases.

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When a liquid changes to a gas, the phase change is called vaporization.

A substance vaporizes as the temperature increases.

When a gas changes to a liquid, the phase change is called condensation.

A substance condenses as the temperature decreases.

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Example: Liquid Chlorine is chlorine gas compressed

usually in a 1 ton or 150 lb container

Under pressure in the container but using a vacuum chlorinator, can drawn and injected into the water flow for disinfection

Biggest concern is safety and temperature increases 18

When a solid changes directly to a gas, the phase change is called sublimation.

A substance sublimes as the temperature increases.

When a gas changes directly to a solid, the phase change is called deposition.

A substance undergoes deposition as the temperature decreases.

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Examples of Sublmination: Iodine

Dry ice (CO2)

Naphthalene (moth balls)

Ice cubes

(frost free refrigerators)

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Examples of Deposition: CO2 gas can be made directly into dry ice

(opposite)

water vapor in very cold air can turn directly to snow or frost on a window

Iodine vapors (purple ) will

become needle crystals of

black iodine solid

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Matter can be divided into two classes: mixtures

pure substances

Mixtures are composed of more than one substance and can be physically separated into its component substances.

Pure substances are composed of only one substance and cannot be physically separated.

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There are two types of mixtures: homogeneous mixtures

heterogeneous mixtures

Homogeneous mixtures have uniform properties throughout. Salt water is a homogeneous mixture.

Heterogeneous mixtures do not have uniform properties throughout. Sand and water is a heterogeneous mixture.

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Mixtures Homogeneous

Mixtures which are the same throughout with identical properties everywhere in the mixture.

Not easily separated. This type of mixture is called a solution. A good

example would be sugar dissolved in water or some type of metal alloy like the CROmium-MOLYbdenum steel used in many bike frames.

Heterogeneous Mixtures which have different properties when

sampled from different areas. Examples of this would be sand mixed with

water or peanuts mixed with raisins.26

There are two types of pure substances: compounds

elements

Compounds can be chemically separated into individual elements. Water is a compound that can be separated

into hydrogen and oxygen.

An element cannot be broken down further by chemical reactions.

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a single atom(of an element)

a molecule(of an element)

a molecule(of a compound)

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There are over 100 elements that occur in nature; 81 of those elements are stable.

Only 10 elements account for 95% of the mass of the Earth’s crust:

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Oxygen is the most common element in both the Earth’s crust and in the human body.

While silicon is the second most abundant element in the crust, carbon is the second most abundant in the body.

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Each element has a unique name.

Names have several origins: hydrogen is derived from Greek

carbon is derived from Latin

scandium is named for Scandinavia

nobelium is named for Alfred Nobel

yttrium is named for the town of Ytterby, Sweden

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Each element is abbreviated using a chemical symbol.

The symbols are 1 or 2 letters long.

Most of the time, the symbol is derived from the name of the element. C is the symbol for carbon

Cd is the symbol for cadmium

When a symbol has two letters, the first is capitalized and the second is lowercase.

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For some elements, the chemical symbol is derived from the original Latin name.

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Gold – Au Sodium – Na

Silver – Ag Antimony – Sb

Copper – Cu Tin – Sn

Mercury – Hg Iron – Fe

Potassium – K Tungsten – W

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Atomic Name SymbolNumber ----------------------------------------------------------1 Hydrogen H2 Helium He3 Lithium Li4 Beryllium Be5 Boron B6 Carbon C7 Nitrogen N8 Oxygen O9 Fluorine F10 Neon Ne11 Sodium Na12 Magnesium Mg13 Aluminium Al14 Silicon Si15 Phosphorus P16 Sulphur S17 Chlorine Cl18 Argon Ar19 Potassium K20 Calcium Ca

Elements can be divided into three classes: metals

nonmetals

semimetals or metalloids

Semimetals have properties midway between those of metals and nonmetals.

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Metals are typically solids with high melting points and high densities and have a bright, metallic luster.

Metals are good conductors of heat and electricity.

Metals can be hammered into thin sheets and are said to be malleable.

Metals can be drawn into fine wires and are said to be ductile.

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Nonmetals typically have low melting points and low densities and have a dull appearance.

Nonmetals are poor conductors of heat and electricity.

Nonmetals are not malleable or ductile and crush into a powder when hammered.

11 nonmetals occur naturally in the gaseous state.

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Each element is assigned a number to identify it. It is called the atomic number.

Hydrogen is 1; helium is 2; up to uranium, which is 92.

The elements are arranged by atomic number on the periodic table.

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Metals are on the left side of the periodic table, nonmetals are on the right side, and the semimetals are in between.

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Shown are the physical states of the elements at 25 °C on the periodic table.

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The law of definite composition states that “Compounds always contain the same elements in a constant proportion by mass.”

Water is always 11.19% hydrogen and 88.81% oxygen by mass, no matter what its source.

Ethanol is always 13.13% hydrogen, 52.14% carbon, and 34.73% oxygen by mass.

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A particle composed of two or more nonmetal atoms is a molecule.

A chemical formula expresses the number and types of atoms in a molecule.

The chemical formula of sulfuric acid is

H2SO4.47

The number of each type of atom in a molecule is indicated with a subscript in a chemical formula.

If there is only one atom of a certain type, no ‘1’ is used.

A molecule of the vitamin niacin has 6 carbon atoms, 6 hydrogen atoms, 2 nitrogen atoms, and 1 oxygen atom. What is the chemical formula?

C6H6N2O 48

Some chemical formulas use parentheses to clarify atomic composition.

Ethylene glycol, a component of some antifreezes, has a chemical formula of C2H4(OH)2. There are 2 carbon atoms, 4 hydrogen atoms, and 2 OH units, giving a total of 6 hydrogen atoms and 2 oxygen atoms. How many total atoms are in ethylene glycol?

Ethylene glycol has a total of 10 atoms.49

A physical property is a characteristic of a pure substance that we can observe without changing its composition.

Physical properties include appearance, melting and boiling points, density, conductivity, and physical state.

A chemical property describes the chemical reactions of a pure substance.

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A physical change is a change where the chemical composition of the substance is not changed.

These include changes in physical state or shape of a pure substance.

A chemical change is a chemical reaction.

The composition of the substances changes during a chemical change.

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http://www.elmhurst.edu/~chm/vchembook/105Achemprop.html

gas release (bubbles)

light or release of heat energy

formation of a precipitate

a permanent color change

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Sodium metal (Na) reacts withchlorine gas (Cl2)

to producesodium chloride (NaCl).

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Antoine Lavoisier found that the mass of substances before a chemical change was always equal to the mass of substances after a chemical change.

This is the law of conservation of mass.

Matter is neither created nor destroyed in physical or chemical processes.

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If 1.0 gram of hydrogen combines with 8.0 grams of oxygen, 9.0 grams of water is produced.

Consequently, 3.0 grams of hydrogen combine with 24.0 grams of oxygen to produce 27.0 grams of water.

If 50.0 grams of water decompose to produce 45.0 grams of oxygen, how many grams of hydrogen are produced?

50.0 g water – 45.0 g oxygen = 5.0 g hydrogen 55

Potential energy, PE, is stored energy; it results from position or composition.

Kinetic energy, KE, is the energy matter has as a result of motion.

Energy can be converted between the two types.

A boulder at the top of the hill has potential energy; if you push it down the hill, the potential energy is converted to kinetic energy.

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All substances have kinetic energy no matter what physical state they are in.

Solids have the lowest kinetic energy, and gases have the greatest kinetic energy.

As you increase the temperature of a substance, its kinetic energy increases.

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Just like matter, energy cannot be created or destroyed, but it can be converted from one form to another.

This is the law of conservation of energy.

There are six forms of energy: heat, light, electrical, mechanical, chemical, and nuclear.

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In a chemical change, energy is transformed from one form to another. For example:

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Mass and energy are related by Einstein’s theory of relativity, E = mc2.

Mass and energy can be interchanged.

The law of conservation of mass and energy states that

the total mass and energy of the universe is constant.

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Although aluminum is very abundant in the Earth’s crust, it is difficult to purify it from its ore.

The energy from 8 tons of coal is required to produce 1 ton of aluminum metal from its ore.

However, it only takes the energy from 0.4 tons of coal to produce 1 ton of aluminum from recycled scrap. 62

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Be curious and use your imagination. Explore and

investigate. Quantify and calculate

Even small differences can be important!

Commitment Work regularly and

carefully.

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Learn the vocabulary of chemistry. Definitions of terms. How common vocabulary is applied to chemistry.

Memorize important information. Names, formulas, and charges of polyatomic ions. Solubility rules.

Learn and practice processes. Systematic names and formulas. Dimensional analysis.

Do the questions and exercises in the chapter to test your understanding and help you learn the patterns?

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Quantitative observation.

Comparison to an agreed upon standard.

Every measurement has a number and a unit.

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The unit tells you to what standard you are comparing your object.

The number tells you:1. What multiple of the standard the

object measures.2. The uncertainty in the

measurement.

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Units tell the standard quantity to which we are comparing the measured property. Without an associated unit, a measurement is

without meaning. Scientists use a set of standard units for

comparing all our measurements. So we can easily compare our results.

Each of the units is defined as precisely as possible.

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Scientists generally report results in an agreed upon International System.

The SI System Aka Système International

Quantity Unit Symbol

Length meter m

Mass kilogram kg

Time second s

Temperature kelvin K

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Quantity Measured

Name of Unit

Abbreviation

Mass gram g

Length meter m

Volume liter L

Time seconds s

Temperature Kelvin K

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Measure of the two-dimensional distance an object covers.

SI unit = meter About 3½ inches longer than a yard.

1 meter = one ten-millionth the distance from the North Pole to the Equator = distance between marks on standard metal rod in a Paris vault = distance covered by a certain number of wavelengths of a special color of light

Commonly use centimeters (cm). 1 cm ~ width of your pinky nail 1 m = 100 cm 1 cm = 0.01 m = 10 mm 1 inch = 2.54 cm (exactly)

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Measure of the amount of matter present in an object.

SI unit = kilogram (kg) About 2 lbs. 3 oz.

Commonly measure mass in grams (g) or milligrams (mg). 1 kg = 2.2046 pounds, 1 lbs. =

453.59 g 1 kg = 1000 g = 103 g, 1 g = 1000 mg = 103 mg 1 g = 0.001 kg = 10-3 kg, 1 mg = 0.001 g = 10-3 g

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Measure of the duration of an event.

SI units = second (s) 1 s is defined as the period of

time it takes for a specific number of radiation events of a specific transition from cesium-133.

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Measure of the average amount of kinetic energy. higher temperature = larger

average kinetic energy Heat flows from the matter that

has high thermal energy into matter that has low thermal energy. Until they reach the same

temperature. Heat is exchanged through

molecular collisions between the two materials.

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Prefix SymbolDecimal

EquivalentPower of 10

mega- M 1,000,000 Base x 106

kilo- k 1,000 Base x 103

deci- d 0.1 Base x 10-1

centi- c 0.01 Base x 10-2

milli- m 0.001 Base x 10-3

micro- or mc 0.000 001 Base x 10-6

nano- n 0.000 000 001 Base x 10-9

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Derived unit. Any length unit cubed.

Measure of the amount of space occupied.

SI unit = cubic meter (m3) Commonly measure solid volume

in cubic centimeters (cm3). 1 m3 = 106 cm3 1 cm3 = 10-6 m3 = 0.000001 m3

Commonly measure liquid or gas volume in milliliters (mL). 1 L is slightly larger than 1 quart. 1 L = 1 dm3 = 1000 mL = 103 mL 1 mL = 0.001 L = 10-3 L 1 mL = 1 cm3

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Length

1 kilometer (km) = 0.6214 mile (mi)

1 meter (m) = 39.37 inches (in.)

1 meter (m) = 1.094 yards (yd)

1 foot (ft) = 30.48 centimeters (cm)

1 inch (in.) = 2.54 centimeters (cm) exactly

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Volume

1 liter (L) = 1000 milliliters (mL)

1 liter (L) = 1000 cubic centimeters (cm3)

1 liter (L) = 1.057 quarts (qt)

1 Imp. gallon (gal) = 4.546 liters (L)

Mass

1 kilogram (km) = 2.205 pounds (lb)

1 pound (lb) = 453.59 grams (g)

1 ounce (oz) = 28.35 (g)

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Always write every number with its associated unit.

Always include units in your calculations. You can do the same kind of operations on

units as you can with numbers. cm × cm = cm2

cm + cm = cm cm ÷ cm = 1

Using units as a guide to problem solving is called dimensional analysis.

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Many problems in chemistry involve using relationships to convert one unit of measurement to another.

Conversion factors are relationships between two units. May be exact or measured. Both parts of the conversion factor have the

same number of significant figures. Conversion factors generated from

equivalence statements. e.g., 1 inch = 2.54 cm can give or

in1

cm54.2cm54.2

in1

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Arrange conversion factors so the starting unit cancels. Arrange conversion factor so the starting unit

is on the bottom of the conversion factor. May string conversion factors.

So we do not need to know every relationship, as long as we can find something else the starting and desired units are related to :

unit desired unit related

unit desired

unitstart

unit relatedunitstart

unit desired unitstart

unit desiredunitstart

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Ratio of mass:volume. Its value depends on the kind of material,

not the amount. Solids = g/cm3

1 cm3 = 1 mL Liquids = g/mL Gases = g/L Volume of a solid can be determined by

water displacement—Archimedes Principle.

Density : solids > liquids > gases Except ice is less dense than liquid water!

Volume

MassDensity

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For equal volumes, the more dense object has a larger mass.

For equal masses, the more dense object has a smaller volume.

Heating objects causes objects to expand. This does not effect their mass! How would heating an object effect its

density? In a heterogeneous mixture, the more

dense object sinks. Why do hot air balloons rise?

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VolumeMass

Density

DensityMass

Volume

Volume Density Mass

Solution Maps:

m, V D

m, D V

V, D m

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Sometimes you can determine an exact value for a quality of an object. Often by counting.

Pennies in a pile. Sometimes by definition

1 ounce is exactly 1/16th of 1 pound.

Whenever you use an instrument to compare a quality of an object to a standard, there is uncertainty in the comparison.

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Measurements are written to indicate the uncertainty in the measurement.

The system of writing measurements we use is called significant figures.

When writing measurements, all the digits written are known with certainty except the last one, which is an estimate.

45.872

CertainEstimated

45.872

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For instruments marked with a scale, you get the last digit by estimating between the marks.

If possible. Mentally divide the space

into 10 equal spaces, then estimate how many spaces over the indicator is.

1.2 gramsthe “1” is certain;

the “2” is an estimate.

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The non-placeholding digits in a reported measurement are called significant figures. Some zeros in a written number

are only there to help you locate the decimal point.

Significant figures tell us the range of values to expect for repeated measurements. The more significant figures

there are in a measurement, the smaller the range of values. Therefore, the measurement is more precise.

12.3 cmhas 3 significant figures

and its range is12.2 to 12.4 cm.

12.30 cmhas 4 significant figures

and its range is12.29 to 12.31 cm.

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All non-zero digits are significant. 1.5 has 2 significant figures.

Interior zeros are significant. 1.05 has 3 significant figures.

Trailing zeros after a decimal point are significant. 1.050 has 4 significant figures.

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Leading zeros are NOT significant. 0.001050 has 4 significant figures.

1.050 x 10-3

Zeros at the end of a number without a written decimal point are ambiguous and should be avoided by using scientific notation.

If 150 has 2 significant figures, then 1.5 x 102, but if 150 has 3 significant figures, then 1.50 x 102.

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Exact numbers have an unlimited number of significant figures.

A number whose value is known with complete certainty is exact. From counting individual objects. From definitions.

1 cm is exactly equal to 0.01 m. From integer values in equations.

In the equation for the radius of a circle, the 2 is exact.

radius of a circle =diameter of a circle

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Matter exists in three physical states: solid

liquid

gas

Substances can be converted between the three states.

Substances can be mixtures or pure substances.

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Pure substances can be either compound or elements.

The elements are arranged in the periodic table.

Each element has a name and a 1- or 2-letter symbol.

Elements are classified as either metals, nonmetals, or semimetals.

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A physical change is a change in physical state or shape.

A chemical change is a change in the chemical composition of a substance.

Both mass and energy are conserved in chemical and physical changes.

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The law of definite composition states that “Compounds always contain the same elements in a constant proportion by mass.”

This is the law of conservation of mass that “Matter is neither created nor destroyed in physical or chemical processes.”

This is the law of conservation of energy that “There are six forms of energy: heat, light, electrical, mechanical, chemical, and nuclear.”

The law of conservation of mass and energy states that the total mass and energy of the universe is constant.

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Measurement and associated units

Length, Mass, Time, Volume, Temperature

Conversion of Units and Dimensional Analysis

Density

Reporting Measurements - significant figures

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