Presentation on theme: "Matter & Properties of Matter 8 th Grade Science."— Presentation transcript:
Matter & Properties of Matter 8 th Grade Science
What is Matter? Anything that has mass & takes up space
Matter is either… Substance Single kind of matter, fixed composition Examples: Table salt, sugar, baking soda, or Not Substance More than a single kind of matter, composition can change Examples: muffin mix (made up of substance), flour, milk, eggs, fruit
Properties of Matter Physical properties are characteristics that can be observed without changing the matter into another substance Chemical properties are characteristics that describe the ability to change into another substance
Examples of Each Physical Properties Water freezing to ice at 32°F Whether or not a substance dissolves in water Texture Color Chemical Properties Chemicals that are combustible vs. ones that are not rusting
Elements Pure substance that cannot be broken down into any other substances Everything is made up of a little more than 100 elements Simplest substances
Particles of Elements Atoms are the particles of elements Atoms are made of even smaller particles: A nucleus which is positively charged and it is surrounded by a cloud of electrons (which have a negative charge).
Chemical bonds When atoms combine they form chemical bonds which is a force of attraction between two or more atoms. In many cases, atoms combine to form larger particles called molecules. Molecules are groups of two or more atoms held together by chemical bonds. Examples: water, oxygen, and carbon dioxide. Water Molecule (H 2 O) Oxygen Molecule (O 2 )
Compounds Compounds are pure substances made of two or more elements chemically combined into a fixed ratio. A compound may be represented by a chemical abbreviation. When two or more elements are placed together the result is a compound which has different characteristics than either of the original elements. Calcium Carbonate (Compound) (Shell of a snail) Calcium (element) Carbon (element) Oxygen (element) CaCO 3
Made of two or more substances (elements, compounds, or both) They are NOT chemically combined Can be separated physically Each substance in a mixture keeps its individual properties Give some examples of mixtures Salt water, soil, bag of marbles What is a Mixture?
Heterogeneous Mixtures A heterogeneous mixture is when two or more substances are mixed but do not combine chemically to form a single substance. Examples: salad, oil and water, rocks, chocolate chip cookie, chicken soup, etc. We can separate all the components of the salad to the left, so it is a heterogeneous mixture.
Homogenous Mixture A homogeneous mixture is what you have when you mix two or more substances together so that the composition is the same throughout the mixture. Examples: sugar and water, brass (mixture of copper and zinc), air that we breathe (oxygen and nitrogen gases), soft drinks, milk, etc. A solution is an example of an homogeneous mixture.
The two types of changes in matter Physical changes: any change that alters the form or appearance of the matter, but does not alter the properties of the matter. A substance that undergoes a physical change is still the same substance after the change. Example: water exists as a solid, liquid, or a gas. Chemical changes: any change which results in the production of one or more new substances is a chemical change. The properties of the new substances are different than the properties of the original substances. Example: Hydrogen peroxide turns into water and oxygen gas when it is used.
Law of the conservation of matter Simply stated that when matter changes either chemically or physically, that matter is not created nor destroyed, it has just changed to another form or forms. Example: CH4 (methane) + 2O2 (oxygen) = CO2 (carbon dioxide) + 2H2O (water) Notice how the number of atoms did not change after the combustion.
Matter is neither created nor destroyed: Before the reaction CH 4 (methane) + 2O 2 (oxygen) The total number of atoms before the reaction is: 1 Carbon (C) 4 Hydrogen (H) 4 Oxygen (O) After the reaction CO 2 (carbon dioxide) + 2H 2 O (water) The total number of atoms after the reaction is: 1 Carbon (C) 4 Hydrogen (H) 4 Oxygen (O)