1. Chemical Reactions

2. Performance Expectations
MS-PS1-5. I can explain the conservation of mass through a model of chemical reactions.
MS-PS1-3 I can gather information to describe the origins and impacts of synthetic material

3. What is a chemical reaction?
When elements and/or compounds interact to form new compounds
A new substance is made during a chemical reaction

4. 2 H2 + O2  2 H2O Chemical Equations
We use chemical equations to represent the chemical reaction with chemical formulas and numbers.
2 H2 + O2  2 H2O
This is the chemical equation showing how hydrogen and oxygen react to make water

5. Parts of a Chemical Equation Reactants and Products
Chemical reactions are read left to right.
The starting substances are called the reactants
The substance that is made as a result of the chemical reaction are called products
2 H2 + O2  2 H2O
Reactants
Products

6. Parts of a Chemical Equation Chemical Formulas
A chemical formula is a why to represent a substance.
Atomic Symbols- from the periodic table to represent the types of atoms in the substance
Subscripts- tell the number of each type of atom in a molecule
2 H2 + O2  2 H2O
H2 is the chemical formula for a hydrogen molecule.
H2O is the chemical formula for a water molecule

7. Parts of a Chemical Equation Coefficients
Coefficients tell us the proportions that the molecules need to react in.
They show how matter is conserved
2 H2 + O2  2 H2O
The coefficient of 2 shows us that two molecules of hydrogen need to react for every 1 molecule of oxygen
Not having coefficient is the same as saying 1

8. How Do I know a Chemical Reaction Happened
You may not be able to see the molecules but there are some signs that a reaction has occurred
Color Change
Creation of a New Gas
Change in Temperature
Smell
Light

9. Vocabulary Pt II.

10. Chemical formula
A representation of a substance in which the elements are represented by their symbols and subscripts represent the number of atoms of each element
H2O

11. Chemical change
The formation of a new substance with different properties; cannot be undone by physical means

12. 2 H2 + O2  2 H2O Chemical equation
A representation of a chemical reaction by symbols and numbers
2 H2 + O2  2 H2O

13. Law of conservation of mass
Matter is not created or destroyed; only rearranged

14. Product
Substance(s) resulting from a chemical reaction

15. Reactant
Substances that are combined and changed during a chemical reaction

16. Element
A substance made of only one kind of atom.

17. Synthetic
Made by human means and not originally found in nature.