Unit 3 – Matter
Unit Big Idea: Matter is described by its properties and may undergo changes.
Lesson 1 – Introduction to Matter
Essential Question: What properties define matter?
By the end of this lesson, you should be able to relate mass, weight, volume, and density to one another.
- Matter – anything that has mass and takes up space – makes up materials around you (ex: your body,
water, air) - light and sound are NOT matter
- Mass – amount of matter in an object
- unit of measure is grams (g) – base unit kilograms (kg)
- DOES NOT change depending on where you are – moon or Earth
- measured using a triple beam balance or electric balance
- Weight – measure of the gravitational force on an object – weight will change depending on how much
gravity is pulling you down – you weigh less on the moon than on Earth since the moon has less
gravitational force pulling on you
- measured using spring scale
- measurement given in units of force – Newton (N) - 100g mass is ≈ 1 N on Earth ≈ ¼ pound
- Volume – amount of space an object takes up
- volume of a rectangular box is volume = length x width x height (V=lwh) given in units cm3
- volume of liquids are measured with graduated cylinder or beaker
- water displacement measures volume of irregular shaped solid objects by sinking them in water
and measuring the difference
- units liter (L), milliliter (mL) 1 milliliter (mL) = 1 cubic centimeter (cm3)
- Density– amount of mass in a given volume
- remains the same no matter how much of the substance you have
- density = mass / volume D=M/V
- units are grams per cubic centimeter (g/cm3) for solids & grams per milliliter (g/mL) for liquids
- density of water is 1 g/mL (g/cm3) – any object with a greater density sinks & objects with less
density float
Lesson 2 Properties of Matter
Essential Question: What are physical and chemical properties of matter?
By the end of this lesson, you should be able to classify and compare substances based on their physical
and chemical properties.
- Physical property – characteristic of substance that can be observed and measured without changing
the identity of the substance
- senses can be used to detect physical properties – color, shape, size, odor, texture, etc
- does not change when observed or measured even when measuring boiling or freezing point
- can describe how the substance can be useful
- examples: density (mass/volume), electrical conductivity (how well an electrical current can
move through a substance), thermal conductivity (rate a substance transfers heat), malleability
(ability of substance to be rolled or pounded into various shapes), luster (shine), melting point
(temperature where substance changes from a solid to a liquid), boiling point (temperature
where substance changes from a liquid to a gas), magnetic attraction (attracts metals to it)
- Chemical property – describes substance’s ability to change into a new substance with different
properties
- common ones: flammability (ability to burn) & reactivity with substances like oxygen, water,
aids, and bases to form a new substance or substances (like rust or tarnish in contact with
oxygen)
- changes the original substance into new substances
- each SI unit is represented by a symbol and measured with a specific tool or set of tools
- changing from one unit to another is easier because SI units are based on the number 10 – to
convert from one unit to another multiply or divide by a multiple of 10 (in other words move the
decimal either right or left by the number of zeros in the number you are multiplying or dividing
by)
- describes which chemical change can or cannot happen to a substance
- Nanotechnology – use of designed materials and processes on the atomic scale
- ex: small electrical circuits, machines, and medical delivery systems
- materials built by putting atoms together
- Characteristic properties – properties unique to a substance
- stay the same no matter how much of the substance is used – help identify the substance
Lesson 3 – Physical and Chemical Changes
Essential Question: What are physical and chemical changes of matter?
By the end of this lesson, you should be able to distinguish between physical and chemical changes of
matter.
- Physical change – change that affects one or more physical properties of a substance
- occurs when substance changes from one form to another (chemical identify stays the same)
- ex: change in size, freezing, bending, flattening, pulling into a new shape, dissolving it in water
- Chemical change – occurs when one or more substances change into entirely new substances with
different properties.
- not same as chemical properties – burning is a chemical change whereas flammability is a
chemical property
- processes by which substances actually change into new substances
- identity changes because its chemical makeup changes – chemical bonds are rearranged
- often influenced by temperature since at higher temperatures particles in a substance have more
average kinetic energy and move around more freely and rearrange more easily
- chemical changes happen more quickly at higher temperatures
- Signs a chemical change has occurred – need two or more of these signed during a change for it to be a
chemical change
- production of gas – seen as fizzing or foaming (ex: dropping antacid tablet into water)
- production of an odor (ex: egg rotting, milk souring)
- formation of a precipitate – solid formed when two or more liquids combine – solid sinks to the
bottom of the container
- change in energy - energy changing from chemical energy to heat and light energy; can been
seen as change in temperature as well (ex: burning of candle)
- change in color (ex: gray iron rusts to a red color)
- Law of conservation of mass – in ordinary chemical and physical changes, mass is not created or
destroyed – mass is only transformed into different substances
- first proved by French chemist Antoine Lavoisier in 1770s
- Law of conservation of energy – energy cannot be created or destroyed – can only change from one
form to another by being released or absorbed during physical and chemical changes
- endothermic – change that absorbs energy
- exothermic – change that releases energy
Lesson 4 – Nuclear Reactions
Essential Question: How do nuclear reactions differ from chemical reactions?
By the end of this lesson, you should be able to distinguish nuclear reactions from chemical reactions and
compare the types of nuclear reactions.
- French physicist Henri Becquerel discovered energy released from uranium ore produced an image on a
photographic plate, even in the dark in 1896
- Marie and Pierre Curie discovered new elements of polonium and radium- energy released as a result of
a nuclear reaction
- Nuclear reaction – change that affects the nucleus of an atom - different from a chemical change
- change the mass of atoms by a very small amount – mass is changed into energy that’s released
during the reaction
- amount of energy produced from a certain mass is calculated by equation E=mc2
- E = energy; m = mass; c = speed of light
- speed of light = 3.00 x 108 m/s
- this means a small amount of mass changes into a really large amount of energy
- changes the nucleus of an atom
- can change identify of atom by changing number of protons in the nucleus (ex: beryllium atoms
loses protons and becomes lithium)
- changing number of neutrons in the nucleus DOES NOT change the identity of the atom
- Isotope – atoms with the same number of protons but different numbers of neutrons
- ex: lithium-6 has 3 protons & 3 neutrons; lithium-7 has 3 protons & 4 neutrons – the
mass number changes not the atomic number (number of protons)
- Radioactive decay – nuclear reaction in which an unstable nucleus can give off energy and, sometimes
particles
- nuclear radiation – particles & energy given off
- unstable nuclei continue to decays until they form stable nuclei
- 3 kinds of radioactive decay – alpha decay, beta decay, & gamma decay
- alpha decay – release of an alpha particle & energy from a radioactive nucleus
- alpha particle is two protons & two neutrons – same as a helium nucleus – charge of 2+
- produces atoms of a different element since it reduces number of protons in the nucleus
- beta decay – releases beta particle & energy
- two types beta particles – positrons & electrons – both have a mass of about zero (0)
- positrons have a charge of 1+
- electrons have a charge of 1- proton can break into neutron with positron released
- neutron can break into proton with electron released
- changes nucleus into different element
- atomic number increases when electrons released
- atomic number decreases when positrons released
- gamma decay – releases gamma rays – high energy radiation with no mass or charge
- does not change the number of particles in the nucleus – doesn’t form different element or
isotope
- some of energy released during alpha & beta decay is in the form of a gamma ray
- different decay particles affect matter differently because the radiation they produce has different
masses, charges, & energy.
- alpha particles have largest mass & charge, losing energy quickly so they don’t penetrate deeply
but can damage living cells & break apart chemical bonds when they hit a substance – can be
stopped with paper or cloth
- beta particles have a small mass and small charge and break bonds in molecules of cells & cause
illness – can be stopped by plastic, wood, aluminum and other thin metals
- gamma particles easily pass through most matter because they have high energy and no mass or
charge - can remove electrons from atoms which weaken metals and damages cells – causes
radiation sickness – fatigue, vomiting, hair loss, etc – long term exposure increases risk of
cancer – can be stopped by thick walls of concrete
- radioactive decay used in many ways: make smoke detectors work; sterilize bandages; test thickness of
metal sheets; find leaks in pipes; find age of fossils, artifacts, rocks, bones, cloth, the canvas of
paintings, age of paints on a painting, etc; find and treat disease
- used in medicine to detect & treat cancer; gamma knife used to destroy brain tumors; positron
emission tomography (PET) cans used to find tumors in the brain; radioactive tracers also detect
cancer in bones
- Nuclear fission – nuclear reaction where a large, unstable nucleus breaks into two smaller nuclei
- smaller nuclei are more stable than larger ones
- releases neutrons & a large amount of energy
- changes the nucleus of the atoms it breaks apart
- some atoms undergo nuclear fission naturally and break down others can be forced to undergo
nuclear fission by striking them with a neutron breaking apart the nucleus
- nuclear chain reaction – continuous series of fission reactions where the neutrons from one reaction
start another nuclear fission reaction
- gives off huge amounts of energy very quickly
- uncontrolled reactions are used in atomic bombs
- controlled reactions turn the energy released into electrical energy like in nuclear power plants
- Nuclear power plants use energy released during a controlled chain reaction to generate electrical
energy.
- control rods used to absorb neutrons to limit the number of neutrons that are available to
continue the chain reaction
- different from a fossil fuel burning power plant because it uses a different type of fuel
- advantages: produces large amounts of energy from small amounts of fuel; cost of fuel is less
making electricity prices cheaper; doesn’t produce greenhouse gasses or other air and water
pollution as fossil fuel power plants do
- disadvantages: explosions can send large amounts of radioactive materials into the atmosphere
& contaminate ground water though rare are still a risk; smaller accidents can cause radioactive
materials to leak into the environment harming plants, animals, & humans; not a renewable
resource with limited supplies of uranium; some of the products created during nuclear fission
are radioactive & the waste must be properly stored for thousands or millions of years before it
is no longer highly radioactive
- Nuclear Fusion – process where nuclei of small atoms combine to form a new, more massive nucleus
- type of energy given off by the sun and other stars
- uses extremely high temperatures & pressure to force nuclei together
- changes small amount of mass into a large amount of energy
- sun produces helium nucleus, beta particles, & energy from hydrogen nuclei that travels to Earth
as heat and light
- scientists trying to develop nuclear fusion power plants – unlimited source of energy – could be
energy source of the future
- challenges: hard to produce conditions to start & keep nuclear fusion reactions going on
Earth; difficult to contain reactions; requires large amounts of energy to get temperatures
high enough to start reaction; no known material that can sustain this high reaction
temperature; currently more energy is needed to produce the conditions needed for fusion
than can be produced by the fusion reaction itself
- potential benefits: hydrogen fuel needed is easy to come by & lots of it (makes up
water) – not renewable but have almost unlimited supply on Earth; doesn’t create
radioactive waste or greenhouse gases; doesn’t produce high levels of radiation during
the process so an accident with a fusion reactor would not release large amounts of
nuclear radiation into the environment
Lesson 5 – Pure Substances and Mixtures
Essential Question: How do pure substances and mixtures compare?
By the end of this lesson, you should be able to distinguish between pure substances and mixtures.
- Atoms – smallest unit of an element that maintains the properties of that element
- can be combined in different ways to produce different substances
- basic building blocks for elements, compounds, & mixtures
- Element - made up of one or more of the same kind of atom chemically combined (ex: oxygen)
- Compound - made up of different kinds of atoms chemically combined. (ex: water)
– have different properties form the elements that make them up
- Mixture – contains a variety of elements and compounds that are not chemically combined with each
other. (ex: nitrogen, oxygen, and water vapor in the air)
- Pure substance - substance that has definite physical and chemical properties such as appearance,
melting point, and reactivity (ex: elements & compounds)
- will always have the same properties no matter the amount of that substance or where it is found
on Earth or in space
- melting, freezing, cutting, smashing, etc don’t change the identity of the pure substance –
chemical bonds holding them together can’t be broken easily
- requires a chemical change to break or form the chemical bonds and it’s then no longer the
original substance
- Classifying Elements by physical and chemical properties
- by knowing the category an element belongs you can predict some of its properties
- broad classifications of metal, nonmetals, or metalloids
- most metals are shiny, conduct heat & electricity well, can be shaped into thin sheets or wires
- nonmetals are not shiny, & don’t conduct heat or electricity well
- metalloids have some properties of both metals & nonmetals
- periodic table is a tool used to arrange elements and identify elements with similar properties (metals
on left, nonmetals on right, with metalloids in middle)
- Classifying Compounds by grouping them into few basic categories by their properties
- pH – acidic, basic, or neutral
- acids have pH below 7 have sharp, sour taste (ex: acetic acid in vinegar, lemon juice);
- bases have pH greater than 7 have slippery feel & bitter taste (ex: baking soda, shampoo);
- neutral compounds have pH of 7 (ex: pure water or table salt) and are formed when acid & base
react
- litmus paper used to test for acid or base (red litmus paper turns blue in an acid; blue litmus
paper turns red in a base)
- NEVER taste, smell, or touch a chemical to classify them
- Organic or Inorganic
- organic compounds have carbon and oxygen – found in most foods
- Role in the body
- biochemicals – organic compounds made by living things
- four categories: carbohydrates, lipids, proteins, & nucleic acids
- carbohydrates used as source of energy (ex: sugars, starches, fiber)
- lipids store excess energy in body & make up cell membranes
- proteins regulate chemical activities of the body, build & repair body structure - one of most
abundant types of compounds in body (remember ribosomes makes protein to speed up chemical
reactions like cellular respiration to release energy & lysosome repairing cell organelles)
- nucleic acids such as DNA & RNA contain genetic information & help build proteins
- Mixtures aren’t pure substances since they are made of more than one type of substance that aren’t
chemically combined
- each substance in the mixture has the same chemical makeup it had before the mixture formed
- do not have definite properties because they don’t have definite chemical makeup
- can be separated by physical changes like taking out certain elements, heating to evaporate the
water & leaving the rest behind, magnet used to separate out certain elements, centrifuge used to
spin & separate out densities of components; & filter to separate out parts
- heterogeneous mixture – doesn’t have a uniform composition (ex: soil contains dirt, rocks, leaves,
bugs, and other things of all sizes and amounts)
- suspension – type of heterogeneous mixture where particles of a material are spread throughout
a liquid or gas but are too large to stay mixed without being stirred or shaken – if it sits long the
particles will settle out to the bottom (ex: snow globe, or dirt, sand, branches in a stream)
- colloids are third type of mixture that falls between suspension & solution – look homogeneous
but are consider heterogeneous
- particles are spread throughout a liquid or gas (like in a suspension) but particles are too
small and do not settle out quickly (ex: milk, gelatin)
- homogeneous mixture – substances in a mixture are evenly spread out throughout entire mixture (ex:
sugar dissolved in water)
- solution – type of homogeneous mixture where one substance is dissolved into another
substance – can be gas, liquid, or solid (ex: tea, air, alloys like brass & steel)
Lesson 6 – Acids, Bases, and Salts
Essential Question: What are the properties of acids, bases, and salts?
By the end of this lesson, you should have an understanding of the physical and chemical properties of
acids, bases, and salts and how these chemicals are commonly used.
- acids & bases are chemicals that increase the number of ions present when they dissolve in water
- acid – increases the number of positively charged H3O+ ions to the solution when it dissolves in water
(ex: lemon juice, vinegar, orange juice, tomato, milk)
- when added to water it increases hydronium ions present in water because the water pulls apart
the acid and mixes the extra hydrogen (H) molecule with water to make H3O+ ions and ions of
what is left of the original acid
- physical properties: taste sour, conduce an electric current (acids are in batteries)
- chemical properties: corrosive (can react with & destroy body tissue, clothing, & other things),
react violently with many metals, react with acid-base indicators to make it change color (litmus
paper) – blue litmus paper turns red in an acid
- base – increases the number of negatively charged OH- ions to the solution when it dissolves in water
(ex: shampoo, window cleaner, soap, baking soda, ammonia, laundry detergent)
- when base dissolves in water the hydroxide group breaks apart to release OH- ions
- physical properties: taste bitter, feel slippery, conduct an electric current (alkaline batteries)
- chemical properties: caustic (can burn or corrode other substances), react with acid-base
indicator to make it change color (litmus paper) – red litmus paper turns blue in a base
- the strength of an acid or base depends on the percentage of its particles that break apart to form ions in
a solution – its strength is not the same as its concentration
- strong acids & bases break apart completely forming many H3O+ ions or OH- ions
- weak acids & bases remain mostly intact with many still whole molecules of the acid or base
that did not break apart in the water
- many insects & sea animals use acids & bases to protect themselves against predators by either
spraying it on them or coating their own body with it so they’ll taste bad
- Neutralization reaction – reaction between an acid & a base in a water solution
- produces water and salt
- water molecules form when the hydrogen ions from the acid combine with the hydroxide ions
from the base making H2O
- salt – ionic compound that forms from the negative ion of the acid and the positive ion of the base
during a neutralization reaction
- ex: sodium chloride (table salt) – used to make baking soda & season food; sodium nitrate
preserves food; calcium sulfate makes plasterboard (drywall); calcium chloride help keep ice
from forming on roads & sidewalks in winter; calcium sulfate is sidewalk chalk
Lesson 7 – States of Matter
Essential Question: How do particles in solids, liquids, & gases move?
By the end of this lesson, you should be able to model the motion of particles in solids, liquids, and gases.
- kinetic theory of matter – all matter is made of atoms or groups of atoms that are in constant motion
- how much a particles moves & bumps into each other determines the state of matter of the
substance
- solid – substance with definite volume & shape – particles close together & don’t move freely
- particles vibrate but are fixed in place – many times particles packed together to form regular
Patterns – doesn’t easily change its shape or volume – can break it into pieces
- generally particles are closer together as a solid than when they are a liquid of the same
substance
– water is an important exception – ice particles have more space between them then water
allowing ice to float (less dense than liquid water)
- liquid – substance with a definite volume but not a definite shape – more kinetic energy than a solid
- particles attracted to each other but not fixed in place and can move from place to place
- takes on the shape of the container it’s put in
- gas - doesn’t have definite volume or shape – particles have the most kinetic energy
- particles not close to each other & can move easily in any direction
- more space between particles than particles in a liquid or solid
- temperature and pressure change can increase or decrease space between gas particles
- motion of the particles changes
- particles in a substance, even solids, are always in motion
- melting – process in which solid becomes a liquid
-
freezing – process in which liquid becomes a solid
boiling – the entire liquid becomes as gas
evaporation – a liquid becomes a gas (at the liquid’s surface only) ex: puddle dries out
condensation – a gas becomes a liquid ex: water forms on outside of cold glass in summer
sublimation – a solid becomes a gas ex: dry ice becomes a gas at room temperature
deposition – a gas becomes a solid ex: frost forms on a cold windowpane
- plasma – 4th state of matter that makes up more than 99% of the matter in the universe
- do not have definite shape or volume life a gas
- blend of negatively and positively charged particles – more energy in particles than in a gas
- conduct electric current – affected by electric & magnetic fields
- ex: sun & other stars, lightening, in fire, in florescent lights, plasma lamps
Lesson 8 – Changes of State
Essential Question: What happens when matter changes state?
By the end of this lesson, you should be able to describe changes of state in terms of the attraction and
motion of particles.
- to change a substance from one state of matter to another, energy must be added to the environment or
removed from the environment
- when substance gains or loses energy, its temperature changes or its state changes but not at the
same time
Solids & Liquids change state
- freezing – change in state when liquid becomes a solid – when cooled its particles have less energy,
slow down in their movement, & the attractions between particles increase (reverse of melting)
- freezing point – temperature at which a liquid changes into a solid
- melting – change in state from a solid to a liquid – when solid is warmed, particles have more energy &
move around more causing decreased attractions between particles until they slide past one another
(reverse of freezing)
- melting point – temperature at which a solid becomes a liquid
Liquids & gases change state
- vaporization – process where a liquid or a solid changes into a gas due to increased amount of energy
- evaporation – process where particles gain energy & escape from the surface of a liquid to become gas
(reverse of condensation)
- happens at the surface of the substance – occurs slowly at lower temperatures and more quickly
at higher temperatures
- boiling – rapid change from a liquid to a gas or vapor
- change takes place throughout the entire liquid, not just at the surface
- boiling point – temperature at which bubbles begin to form in a liquid due to an increase in temperature
- condensation – change in state from a gas to a liquid (reverse of evaporation)
- as gas is cooled particles lose energy & attraction between particles increases
- ex: dew on grass in morning; water droplets on outside of cold glass, contrail lines from a jet
Solids & gases change state
- sublimation – change from a solid directly to a gas – no liquid is formed (reverse of deposition)
- as particles of solid gain energy their motion completely overcomes the attraction between the
particles and the particles escape into the air as gas
- deposition – change in state from a gas directly to a solid – no liquid is formed (reverse of sublimation)
- ex: process where ice crystals form in clouds
- the amount of mass stays the same during a change of state