CATALYST (10 minutes, individual work): Test question. Assignment #1 (New Unit: Reactions) Electrolysis LO: To be able to interpret a chemical equation. EQ: What does it mean for an equation to be balanced? Why should it be balanced? LEVEL ZERO VOICE CATALYST (10 minutes, individual work): Test question. AGENDA Observe video Equations Notes HOMEWORK 1. Finish processing tasks  

Notes side: Observation: written observations and include a labeled diagram

Video: https://www.youtube.com/watch?v=HQ9Fhd7P_HA&t=64s

Observation: written observations and include a labeled diagram

Discussion Questions: Notes side: Discussion Questions: What do you observe happening at the ends of the pins that are in the water? What do you think this gas is made of? The chemical symbol for water is H2O. Do you think there is more hydrogen or oxygen gas being produced when electricity is run through the water? Why do you think this? What do you think would happen if we continued to let this reaction run? be very specific about the properties of the liquid before compared to the properties of the liquid and gas.

Video First viewing: Quietly watch the video. Pay close attention. Second viewing: add to your investigation diagrams and explanations

Video: https://www.youtube.com/watch?v=qHxDHu9wGAw

Video First viewing: Quietly watch the video. Pay close attention. Second viewing: add to your investigation diagrams and explanations

(-lysis means to loosen or break down) electrolysis - to break up a molecule into its parts through electricity (-lysis means to loosen or break down)  

Chemical Equations: Equations that show reactants and products in a chemical reaction Reactant: starting materials (left side of equation) Products: the new substance(s) formed (right side)

H2O → H2 + O2 (Reactants) (Products) unbalanced decomposition reaction (electrolysis) H2O →  H2 + O2 (Reactants) (Products)  

Balanced chemical reaction 2 Sn + O2 → 2 SnO (reactants) (product) tin + oxygen gas → tin oxide (reactants) (product) Balanced chemical reaction 2 Sn + O2 → 2 SnO (reactants) (product)

2H2O → 2H2 + O2 Coefficient: how many molecules or atoms (comes before the atom or molecule) Subscript: the little number in a chemical formula that tells how many atoms of an element are in a molecule

In a chemical reaction, atoms are REARRANGED, not destroyed Law of Conservation of Mass: the total mass before a chemical reaction is the same as the total mass after the reaction In a chemical reaction, atoms are REARRANGED, not destroyed In all chemical reactions, the amount of matter is the same before and after the change takes place No atoms are lost, no atoms are gained

Conservation of mass

Conservation of mass

Conservation of mass

Balance a Chemical Equation When you are writing a chemical equation: Make sure the symbols and formulas for the reactants and products are correct Check to make sure both sides are balanced (same number of each atom appears on each side of the equation – reactants and products) - compare the number of one atom on both sides of the arrow to make sure it’s the same on both sides

Parentheses in Chemical Equations When you count atoms inside a parentheses, the subscript following the parentheses multiplies all the atoms inside. Ca (OH)2 Count the atoms: 1 Ca atoms 2 O atoms 2H atoms

Parentheses in Chemical Equations When you count atoms inside a parentheses, the subscript following the parentheses multiplies all the atoms inside. Ca (OH)2 Count the atoms: 1 Ca atoms 2 O atoms 2H atoms

Video

Write down questions that you got wrong – leave space for answers. Assignment #1 (New Unit: Reactions) Electrolysis LO: To be able to interpret a chemical equation. EQ: What does it mean for an equation to be balanced? Why should it be balanced? LEVEL ZERO VOICE PROCESSING TASK (10 minutes, individual work): Go over test. Write down questions that you got wrong – leave space for answers. Write down correct answers. AGENDA Observe video Equations Notes HOMEWORK 1. Finish processing tasks