Presentation on theme: "Elements, Compounds and Mixtures"— Presentation transcript:
1 Elements, Compounds and Mixtures How does the composition of matter help us explain its diversity and predict its properties?
2 Learning TargetsI can classify matter as a mixture or a pure substance.I know the difference between and element and a compound.I can identify physical properties and give examples of physical changesI can identify chemical properties and give examples of chemical changes.
4 Physical properties and physical change Properties that you can measure or see through direct observation are called physical properties.Ex: phase- Water is a colorless liquid at room temperatureOther examplesMalleability-can be hammered into thin sheetsBrittle- will break if material is hammered or bentDensity- mass per unit of volumeMass- amount of matterPhysical changes- a change in physical properties, such as shape, phase; examples: grinding, melting, boiling, dissolving, heating or cooling.
5 Chemical properties and chemical change Properties that can only be observed when one substances changes into a different substance are called chemical properties.Ex: A chemical property of iron is that it will rust when it reacts with oxygen in the air.Any change that transforms one substance into a different substance is called a chemical change.Evidence of a chemical change:Bubbling- gas is formingTurns cloudy- a new solid is formingTemperature change- chemical bonds are forming or breakingColor change- a new substance is forming.
6 Elements and Compounds Elements are the most fundamental “pure substances” from which all other matter is made. (Ex: oxygen, hydrogen, carbon)The smallest unit of any element is a unique atomElements can not be separated into simpler substances by chemical means.The periodic table organizes the elements according to how they combine with other elements.There are 88 naturally occurring elements.Compounds are substances that contain more than one element in which atoms of different elements are chemically bonded together. (Ex: water, carbon dioxide, sodium chloride)The smallest unit of a compound that retains the identity of that compound is called a molecule.
7 MixturesA mixture is a physical blend of two or more substances that are not chemically combined.Homogeneous mixture- a mixture that contains more than one type of matter and is the same throughout.Ex: lemonade, air, alloys (mixture of metals-like brass)A solution is a mixture that is homogenous on the molecular level (no clumps bigger than a molecule)A solution always has a solvent and a solute.Solvent- substance that makes up the biggest percentage of the mixture and is usually a liquidSolute- the other substance in the solution (sometimes a dissolved solid, like sugar or salt)Heterogeneous mixture- a mixture that contains more than one type of matter and is not the same throughout.Ex: chicken soup, soil, concrete