Law of Conservation of Matter Law of Conservation of Matter C. Gray, 2013 Standard: S8P1g. – Identify and demonstrate the Law of Conservation of Matter

What is a PURE SUBSTANCE? a material with a specific chemical composition.

Examples of PURE SUBSTANCES Au – Gold Li – Lithium Ne – Neon Ca – Calcium Hg – Mercury H 2 O – Water NaCl - Salt

What is a COMPOUND? a thing that is made of two or more chemically bonded materials. It can only be separated by a procedure that breaks those bonds

What is a MIXTURE? A mixture is anything that is made up of two or more physically mixed things. A mixture can be separated without breaking any bonds between the materials in the mixture. Homogeneous Mixtures - components that make up the mixture are uniformly distributed throughout the mixture. (Ex: air, blood, saturated sugar water) Heterogeneous mixtures - components of the mixture are not uniform or have localized regions with different properties. (Ex: Heterogeneous mixtures: rocks, oil and water, soup, pizza)

What is a CHEMICAL FORMULA? a way of expressing information about the proportions of atoms that make up a particular chemical compound.

How do I write a CHEMICAL FORMULA? Subscripts – A subscript looks like this Subscripts are numbers used to tell you how many atoms of an element are present in the equation; for instance: water H 2 0 has 2 atoms of hydrogen and one of oxygen glucose C 6 H 12 O 6 has 6 atoms of carbon, 12 of hydrogen, and 6 of oxygen Coefficients - The large numbers put in front of an equation, either to balance it, or simply to tell you how many molecules there are, in 2H2O, the first '2' is the coefficient, & means that all the atoms following it have to be multiplied by that number - so in 2H2O there are 4 atoms of H, and 2 atoms of 0

Subscript and Coefficient example:

Reactants and Products? In a chemical reaction, substances (elements and/or compounds) called reactants are changed into other substances (compounds and/or elements) called products. You create a new substance with chemical reactions.

Chemical Reactions A number of clues show that a chemical reaction has taken place, for example: – Something new is visibly produced – A gas is created – Heat is given off or taken in In chemical equations, an arrow is used to indicate that a chemical reaction has taken place. In general terms, a chemical reaction follows this format: Reactants→Products

Counting Atoms in a Chemical Reaction Video to demonstratedemonstrate See review worksheet Practice

Law of Conservation of Matter/Mass A law that states that “matter can’t be created or destroyed in a chemical reaction.” It means that the amount of matter going INTO the reaction (the reactants) must be equal to the amount of matter coming OUT of the reaction (the products)

Review activity

Chemical Reactions – click on Bill Nye