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Brawley Middle

Sixth Grade Science

Matter: properties and change

Christophe FattonObjectives 1Recognize that all matter is made up of atoms.Recognize that atoms of the same element are similar, but different from atoms of other elementsDefinition of Matteranything that has mass and takes up spaceWater in a bucket

Key conceptsKey ConceptsChemistry is the study of matter.Matter is made up of extremely tiny particles called atoms and molecules.Atoms and molecules make up the three common states of matter on Earthsolids, liquids, and gases.The particles of a liquid are attracted to one another, are in motion, and are able to move past one another.Being a solid, liquid, or gas is a property of a substance.

Atoms and moleculesAtoms are the tiny particles that are considered to be the basic building blocks of all matter.The nucleus is made of protons and neutrons. The shell has the electrons. The protons and electrons are positively or negatively charged.

Molecules are made of two or more atoms that are connected or bonded together.

MatterSolid, Liquid, GasOn Earth, matter is either found as a solid, liquid, or gas.

MatterSolid, Liquid, Gas particles (atoms or molecules) that make up the solid, liquid, and gas are movingMatter (solid, liquid, and gas) is made up of tiny particles called atoms and molecules.The atoms or molecules that make up matter are always in motion. These first two ideas make up a very important theory called the Kinetic-molecular theory of matter. Basically the state of a sample of matter depends on TEMPERATURE!

MatterSolid, Liquid, GasAtoms or molecules that make up solid, liquid or gas are attracted to one another

Comparing mattersolidsliquidsgasesattractionsAtoms or molecules are very attracted to one anotherAtoms or molecules are attracted to one anotherAtoms or molecules are barely attracted to one anothermovementVibrate but do not move past one anotherVibrate but are able to move past one anotherVibrate and move freely past each otherVolume and shapeHave a definite volume and definite shapeHave a definite volume, but does not have a definite shapeDoes not have definite volume or definite shape

Properties of MatterMatter has both physical and chemical properties.

It can also be classified according to these physical and chemical properties.

Matters Physical PropertiesPhysical properties: can be observed without changing the make-up, or identity, of matter.

Examples of Physical Properties

Physical properties cont..

Matters Chemical PropertiesChemical Property: ability to change new matter with different properties. Chemical Property: new substance has chemical and physical properties different from the original substance. Chemical reaction: When one or more substances change to form one or more new substances.

Chemical Property

Example of Chemical PropertiesChemical PropertyWhat It MeansWhat Students Should UnderstandReactivity with oxygenAbility of a substance to react with oxygenA reaction with oxygen results in processes such as rusting and tarnishing of some metals.Non-reactivity with oxygenAbility of a substance to resist reacting with oxygenNot all substances react with oxygen. This knowledge is used in the real world to prevent rusting and tarnishing. For example, a metal that is reactive with oxygen can be coated or galvanized with a non-reactive substance to prevent rusting or tarnishing. FlammabilityAbility of a substance to burn Everything will burn, given a high enough temperature. When a substance burns, ash and smoke may not be given off. Fumes, which may be toxic, can be a product of the reaction.Non-flammabilityAbility of a substance to resist burningThis property is useful in the real world when selecting certain substances that must withstand extreme heat.Physical and Chemical ChangesPhysical change: only the physical properties of matter, but not the chemical properties.Burning paper into ash Chemical change: demonstrate that new substances can be made when two or more substances are chemically combined and compare the properties of the new substances to the original substancesYou can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes.Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).Characteristics of Physical Changes Melting point Boiling point Vapor pressure ColorState of matterDensityElectrical conductivity Solubility Adsorption to a surfaceHardnessDefinitionsMelting point: the temperature at which a given solid will melt.

DefinitionsBoiling point: The temperature at which a liquid boils and turns to vapor.

DefinitionVolume: The quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains. Volume is often quantified numerically using the SI derived unit, the cubic meter. LXWXH=V

Fahrenheit vs Celsius

DefinitionsDensity: the degree of compactness of a substance. D= m divided by volumedegree of consistency measured by the quantity of mass per unit volume.

MassDefinition: A measure of how much matter is in an object.

Mass is commonly measured by how much something weighs. But weight can change depending on where you are (such as on the moon) while the mass stays the same.Mass is measured in grams, kilograms and, tonnes (Metric) or ounces and pounds (US units)

WeightDefinition the force of gravity on the object and may be defined as the mass times the acceleration of gravity, w = mgGravity= 98.1 m/s2 (meter per second squared)

Characteristic of Chemical ChangesReaction with Acids Reaction with bases (alkalis)Reaction with oxygen (combustion) Ability to act an oxidizing agentAbility to act as reducing AgentReaction with other elements Decomposition into simpler Substances Corrosion(corrodes)Observations of chemical changeFormation of gas (bubbles)Color changeExchange of heat energy (endothermic exothermic reactions)Production of lightPrecipitate forms

Examples of Chemical changeBurning a log of woodFrying or boiling an eggPhotosynthesis - a process in which carbon dioxide and water are changed into sugars by plantsRotting of fruitsRoasting a marshmallowDigestion of foodMoldy cheeseSouring of milkCracking heavy hydrocarbons to create lighter hydrocarbonsBurning of paperPolymerization of gelsDifferent metabolic reactions in the cellsDecomposition of waste in a compost pitComparing Physical and Chemical ChangesDescription Is it Physical? Is it Chemical? Burning coalXMixing salt & pepperXDissolving sugar in teaXMelting an iron rodXA can rustingXCooking scrambled eggsXWater freezing into ice cubesXFireworks explodingXSawing wood to make a cabinetXBread bakingXLaw of conservation of massDefinition: mass is neither created nor destroyed during a chemical reaction it is conserved. Although chemical changes occurred, the total mass involved in the reaction remain constant. Example: If you light a match, it converts the sulfur into gas, and leaves the carbon behind that was there originally, the whole time having the same original mass in the system.

Composition of MatterPure substance: usually referred to a substanceDefinition: matter that has distinct properties and a composition that doesnt vary from sample to sample.Example of pure substance: it can be an element, compound or a mixture.

SubstancesSubstances are either elements or compounds.

Elements: it cannot be decomposed into simpler substances. On the molecular level, each element is compose of only one kind of atoms. Elements

Structure of an atomProtons: positively charged subatomic particle located in the nucleus of an atom. It is counted to identify the atomic numberNeutrons: has the same amount of electrons as protons; they are equal.Electrons: negatively charged subatomic particle located in the electron cloud.

The parts of an atomhttp://www.iknowthat.com/ScienceIllustrations/atoms/science_desk.swf

Compound and MixturesCompound: substances composed of two or more elements, so they contain two or more kinds of atoms.Mixtures: combinations of two or more substances in which each substance retains its own chemical identity.

Compound and mixture