Chemistry Because it matters!!

What is chemistry? Chemistry is the study of matter… Its structure, composition, properties, and the changes it undergoes. What is it made out of? How strong is this material? What happens when I try to burn this substance?

Matter is anything around us the has mass and volume. Matter is anything around us the has mass and volume. Mass =(amt of matter): balance - grams (g) Mass =(amt of matter): balance - grams (g) Volume = (amt of space occupied): Volume = (amt of space occupied): graduated cylinder- milliliters (mL) or metric ruler V = L x W x H – metric ruler V = L x W x H – cubic centimeters (cm 3 ) What is matter?

Making Observations Check out the various samples of matter…….. Check out the various samples of matter…….. What are some things that you can observe about them? What are some things that you can observe about them? Are there any similarities or differences? Are there any similarities or differences?

Classifying Matter Matter can have different phases or physical states…. Matter can have different phases or physical states…. Solid Solid Liquid Liquid Gas Gas The 3 phases differ due to differences in the: 1) arrangement of their particles 1) arrangement of their particles 2) attraction between their particles. 2) attraction between their particles.

Classification of Matter: Element Compound Mixture Matter Pure Substance Mixtures of Substances (fixed composition) (composition varies) Elements Compounds Heterogeneous Homogeneous Suspensions Solutions

Elements vs. Compound There are about 115 different elements. There are about 115 different elements. Elements are pure substances composed of atoms that cannot be broken down any further. Elements are pure substances composed of atoms that cannot be broken down any further. A particular element contains atoms having the same atomic number. A particular element contains atoms having the same atomic number. Some examples: Iron (Fe) or Oxygen (O 2 ) Some examples: Iron (Fe) or Oxygen (O 2 )

Compounds Compounds are pure substances composed of atoms from 2 or more different elements chemically combined in a fixed or definite ratio. Compounds are pure substances composed of atoms from 2 or more different elements chemically combined in a fixed or definite ratio. The compound’s properties are not the same as its component’s original properties. The compound’s properties are not the same as its component’s original properties. Examples: Water (H 2 O) Examples: Water (H 2 O) Sodium Chloride (NaCl) Sodium Chloride (NaCl)

Chemical symbols Elements symbols Elements symbols Use one or two letters to represent name Use one or two letters to represent name Always start with a capital letter Always start with a capital letter If there is a second letter that it is lower case. If there is a second letter that it is lower case. Compounds Compounds Written with two or more capital letters in there symbol. Numbers written as subscripts show the number of elements Written with two or more capital letters in there symbol. Numbers written as subscripts show the number of elements H 2 O 2 hydrogen 1oxygen H 2 O 2 hydrogen 1oxygen MgCl 2 1 magnesium MgCl 2 1 magnesium

1. Elements (made of a single kind of atom) Monatomic Element or Diatomic Element Monatomic Element or Diatomic Element He H 2 He H 2 2. Compounds (hook different atoms together to show they are chemically combined) (hook different atoms together to show they are chemically combined) Water is a compound (H 2 O) Water is a compound (H 2 O) 3. Mixtures (the different substances aren’t hooked – shows they are physically combined) (the different substances aren’t hooked – shows they are physically combined) Mixture of Mixture of Water (H 2 O) & Oxygen (O 2 ) Water (H 2 O) & Oxygen (O 2 ) Models

Vocabulary used to classify matter Substance- matter that you haven’t classified yet. Substance- matter that you haven’t classified yet. Pure substance- same composition and properties though out a given sample Pure substance- same composition and properties though out a given sample Element- matter composed of identical atoms that cannot be further broken down by chemical means. Can be represented with a chemical symbol Element- matter composed of identical atoms that cannot be further broken down by chemical means. Can be represented with a chemical symbol He of helium, C for carbon, or K for potassium. He of helium, C for carbon, or K for potassium. Compound- two or more different elements that at are chemically combined in a fixed ratio. A compound can be broke apart in chemical reaction. Compound- two or more different elements that at are chemically combined in a fixed ratio. A compound can be broke apart in chemical reaction. Ex H 2 O or C 6 H 12 O 6 Ex H 2 O or C 6 H 12 O 6

Vocabulary Cont. Mixture- are composed of two or more different substances that can be seperated by physical means. Mixture- are composed of two or more different substances that can be seperated by physical means. The proportions can be varied The proportions can be varied Each part of the mixture retains it own properties Each part of the mixture retains it own properties

More on Mixtures Heterogenous Heterogenous Visibly different parts which are not in the same amount through out the substance Visibly different parts which are not in the same amount through out the substanceExamples Chex mix Granite Salad dressing Homogeneous Homogeneous looks same though out the sample. Evenly mixed, uniformly distributedExamples Air Kool-aid Apple juice Steel

Special mixtures Solution vs. Suspension Homogenous mixture Solute is dissolved in a solvent. Solute is dissolved in a solvent. Solute is the part being dissolved Solute is the part being dissolved Solvent is the part doing the dissolving Solvent is the part doing the dissolving Heterogeneous Mixture Insoluble solid suspended in a liquid. Insoluble solid suspended in a liquid. Does not dissolve Will settle upon standing