Lesson 1 Introduction to Matter Essential Question: What Properties Define Matter?

Lesson 1 Introduction to Matter Essential Question: What Properties Define Matter?

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 froma radioactive nucleus

- alpha particle is two protons & two neutrons –same as a helium nucleus – charge of 2+

- produces atoms of a different element since itreduces 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 orcharge

- does not change the number of particles in the nucleus – doesn’t formdifferent element or

isotope

- some of energy released during alpha & beta decay is in the form of agamma 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 breaksinto 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 downothers can be forced to undergo

nuclear fission by striking themwith 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 toform a new, more massive nucleus

- type of energy given off by the sun and other stars

- uses extremely high temperatures & pressure to force nucleitogether

- 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 chemicallycombined. (ex: water)

– have different properties form the elements that make them up

- Mixture – contains a variety of elements and compounds that are not chemically combinedwith 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?