Do Now Sit SILENTLY, open your notebooks, and copy down and answer the following question about the video in your notes in your notes. What do you think is the main difference between physical and chemical changes? pqJo

Chemical and physical properties

Matter Flowchart Review MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous MixtureCompoundElement MIXTUREPURE SUBSTANCE yes no Can it be chemically decomposed? noyes Is the composition uniform? noyes

Matter Every element/compound is unique in some way from all others. If you know enough about a substance, you can figure out what it is. If you know what a substance is, you can know all types of things about it.

Matter All matter has 2 types of properties: Physical properties and chemical properties.

Property Is a description of an object The tree is TALL The tree is GREEN If struck by lighting, the tree could catch FIRE (BURN)

Physical Properties Are determined by the use of the. They are a of an object. five senses description

Physical properties A physical property is a characteristic of a substance that can be observed without changing the substance into another substance. – (You can see it without changing what you’re looking at into something else.)

Physical Properties Physical properties can be extensive or intensive: – Extensive properties depend on the amount of a substance that you have. – Intensive properties don’t depend on how much you have.

Physical Properties - Examples Examples of extensive physical properties include: – Volume – Mass – Weight – Density

Volume The amount of space that matter occupies.

Mass A measure of how much matter is in an object.

Weight A measure of the force of gravity on an object.

Density The measurement of how much mass of a substance is contained in a given volume. Mass/Volume

Physical Properties - Examples Examples of intensive physical properties include: – Density – Melting point – Boiling point

Physical Properties - Examples Other physical properties include: – Color – Hardness – Odor – Taste – State of matter – Texture – Luster (shine) – Flexibility – Heat conductivity – Electrical conductivity – Solubility (ability to dissolve in water.) – Shape – Viscosity – Ductility – Malleability

States of Matter There are different “ states ” of matter. No, not like Texas, Oklahoma, New Mexico. States of matter are also known as phases (a physical state of matter). Elements and compounds can move from one phase to another phase when special physical forces are present. Solid Liquid Gas

What is happening at the atomic level

Freezing point The temperature at which a liquid changes into a solid.

B. Four States of Matter Solids – particles vibrate but can ’ t move around – fixed shape – fixed volume – incompressible

Melting point The temperatures at which the solid form of the element or compound is at equilibrium with the liquid form. Basically the range at which the solid changes its state into a liquid. The melting point of water is 0 degrees Celsius

B. Four States of Matter Liquids – particles can move around but are still close together – variable shape – fixed volume – Virtually incompressible

Boiling point The boiling point of an element or compound means the temperature at which the liquid form of an element or compound is at equilibrium with the gaseous form. the boiling point of water is 100 degrees Celsius.

B. Four States of Matter Gases – particles can separate and move throughout container – variable shape – variable volume – Easily compressed – Vapor = gaseous state of a substance that is a liquid or solid at room temperature

B. Four States of Matter Plasma – particles collide with enough energy to break into charged particles (+/-) – gas-like, variable shape & volume – stars, fluorescent light bulbs, TV tubes

Physical properties List as many physical properties as you can for this item

Chemical properties A Chemical property is a characteristic of a substance that can only be observed by changing it into a different substance. /guidConceptId/22cc81ed-8bd3-4b be0242d/guidUnitId/1ef90b7b-c4ee-40d5-bcdc- ff4f708f8873#/tab=explore-tab&page=1&subTab=session5

Chemical properties - Examples Examples of chemical properties include: – The ability to burn – Ability to tarnish – Ability to rust – Ability to decompose – Ability to react with other chemicals – Instability – Ability to do acid/base reactions

Chemical properties List as many chemical properties as you can for this item.

Chemical and physical properties – So what? Titanium is very strong and doesn’t rust, so it is often used in jet engines. Titanium is also nonallergenic. This, combined with the fact that it is rust proof makes it great for artificial joints as well as piercings.

Chemical and physical properties – So what? Tungsten is usually used as the filament in lightbulbs because it has the highest melting point of any metal. It glows red hot when electricity runs through it, and it gives off both heat and light.

Chemical and physical properties – So what? Vanadium is heavier and harder than titanium, so mixing a tiny bit of vanadium with steel can make cheap tools that are still very strong.

Chemical and physical properties – So what? Helium is almost completely nonreactive (inert). It is lighter than air, so it’s great for floating balloons (or making funny voices.) When electricity runs through helium, it glows a creamy pale peach color.

Chemical and physical properties – So what? In 1943, all US pennies were made of zinc plated steel because copper was being used in the war. The pennies had to be coated with zinc because steel will rust, but zinc won’t.

Chemical and physical properties – So what? Sulfur smells awful. Rotten eggs, onions, and garlic all have sulfur in them. Stink bombs use sulfur to create a bad smell. Sulfur is also flammable, and it is one of the 3 main ingredients in gun powder.

Chemical and physical properties – So what? Chromium is famous for its intense luster. Chrome plated tools, jewlery, silverware, or car parts are very popular.

Chemical and physical properties – So what? Most bullets are made of lead because lead is a very dense metal. These bullets are required, by international law, to be coated with a different metal because lead has such a low melting point and is so malleable.

Chemical and physical properties – So what? The most dense elements are Iridium and osmium which have a density of about 22.6 g/cm3

Element abundance The most common element in the universe is Hydrogen (about 75%), and Helium (about 25%). The most common element on Earth is Oxygen (46.6%), and Silicon (27.7%). The most common element in your body is Oxygen (65%), and Carbon (18%)

Physical or Chemical Property? Ability of gun powder and fire to explode. Chemical Property

Physical or Chemical Property? The color of a sunset. Physical Property

Physical or Chemical Property? The ability of a nail to rust. Chemical Property

Physical or Chemical Property? The shape of a leaf. Physical Property

Physical or Chemical Property? The ability of wood to burn. Chemical Property

Physical or Chemical Property? The hardness of a diamond. Physical Property

Physical or Chemical Property? The volume of your coke. Physical Property

Physical or Chemical Property? The mass of two camels. Physical Property

Chemical and physical changes

Physical Change A Physical change is a change in a substance that does not change what the substance is.

Physical Changes a change that occurs changing the of the substance. ____ new substances are formed. without identity No

Examples of Physical Changes Change in size, shape, or color Pencil shavings Torn Paper Crushed ice Sugar dissolved in water Painting a wall

Physical Change - examples Examples of physical change include: – Change in shape – Change in size – Change in phase Melting (solid to liquid) Boiling (liquid to gas) Evaporation (liquid to gas) Condensation (gas to liquid) Freezing (liquid to solid) Sublimation (solid to gas) Deposition (gas to solid)

Physical Change Physical changes might be caused by: – Grinding – Cutting – Crushing – Bending – Breaking – Heating/cooling (change in phase) – squishing

Physical Change Evidence that a physical change has occurred might include: – Change in shape – Change in form – Change in size – Change in phase (This is always a physical change!) – Physical changes are usually reversible

Physical change What could you do to these items to cause a physical change to occur?

Chemical change A chemical change is a change in which a substance is changed into a different substance. (You’ve changed what it is.)

Chemical Changes a change that occurs that the of a substance to change; something is formed. New substances with properties are formed causes identity new

Evidence of Chemical Change New ________appears Bubbbles or ________ Precipitate forms (____ material) _____ is produced ______ is produced ______ is given off Difficult or impossible to __________ color fizzing solid reverse Heat Light Sound

Chemical Change: Evidence Evidence that a chemical change has occurred might include: – A color change – An odor change – Formation of a precipitate (you mix two liquids and make a solid) – Gas is formed (bubbles) – Changes in physical properties.

Chemical change Examples of chemical changes include: – Burning – Rusting – Tarnishing – Decomposing – Polymerization

Chemical change Chemical changes occur when a chemical reaction causes bonds between atoms to break or to form.

Reactions with Acid Vinegar + baking soda = release of Carbon Dioxide Gas

Reactions with Oxygen OXIDATION Iron + Oxygen = rust

Reactions with Electricity Silver Plating

Reactions between Substances Sodium + chloride = salt Silver + sulfer in the air = tarnish

Other Examples Wood burning Metal rusting Food digesting Gasoline burning Cake baking

Physical and Chemical change During a chemical change energy can be released in the form of: – Heat – Light

Chemical change – Chemical reactions When a chemical change occurs, energy is either released or absorbed.

Physical and Chemical change - heat A chemical reaction that releases energy in the form of heat is called exothermic. – Heat comes OUT Exo = out Thermic = heat – It will feel HOT.

Physical and Chemical change - heat A chemical reaction that absorbs energy in the form of heat is called endothermic. – Heat goes IN Endo = in Thermic = heat – It will feel COLD

Physical or Chemical Change? Water evaporates from the ocean.

Physical or Chemical Change? The yolk of an egg, which contains sulfur, causes tarnish to form on silver.

Physical or Chemical Change? The ice on a lake melts to become water in the lake.

Physical or Chemical Change? Charcoal in a fire turns to ash after several hours.

Physical or Chemical Change? A pencil is sharpened in a pencil sharpener, leaving behind shavings.

Physical or Chemical Change? A battery makes electricity to turn on a flashlight.

Physical or Chemical Change? A bicycle rusts when left in the rain.

Physical or Chemical Change? A shirt is accidentally torn in the washing machine.

Physical or Chemical Change? A log is split in two by an axe.

Quiz time! Which life cycle is most similar to a chemical change? Why? Grasshopper = Egg  nymph  adult Butterfly = egg  larva  pupa  adult

Quiz time! What type of reaction is most likely occurring here? How do you know?

Quiz time! What type of reaction is most likely occurring here? How do you know?

Quiz time! What type of reaction is most likely occurring here? How do you know?