Today’s Agenda Bill Nye Chemical Reactions Video (DyKnow questions) Chemical Reactions Tab Chemical Reactions Notebook/Vocabulary

Answer the questions as you watch the video:

CHEMICAL REACTION NOTES

Chemical Formula An expression that shows the number and type of atoms joined in a compound (molecule). SO 2 How many atoms of sulfur (S)? How many atoms of Oxygen (O)?

Subscript A number written slightly below and to the right of a chemical symbol that shows how many atoms of an element are in a compound (molecule). SO 2 subscript

Coefficient The number before a chemical formula that indicates how many sets of the compounds (molecules) are involved in a reaction. 4SO 2 So, its basically telling you there are four SETS of SO 2. How many atoms of Sulfur (S)?_____ How many atoms of Oxygen (O )?_____

Submit when you’re done. Part A: Identify the following parts of each chemical formula by circling the subscripts and drawing a square around the coefficients. Part B: List the symbols for the atoms in each formula and give the number of each. Carbon- ______ Hydrogen- _____ Nitrogen-______ Hydrogen- _____ Magnesium- ______ Oxygen- _____ Phosphorous- ______ Oxygen- _____ Hydrogen- ______ Oxygen- _____ Aluminum- ______ Oxygen- _____ Hydrogen- ______

Chemical reaction The process by which chemical changes occur. There are five signs of a chemical reaction: 1) color change 2) temperature change 3) bubble formed 4) precipitate forms 5) irreversible change occurs In a chemical reaction, atoms are rearranged, and chemical bonds are broken and formed.

Chemical equation a way of writing out the reactants and products in a chemical reaction. reactants → products Reactant Products BaCl 2 + H 2 SO 4 → BaSO HCl A substance that is present at the beginning of a chemical reaction and is changed to a new substance A substance formed by a chemical reaction. A product is made by the rearrangement of atoms and bonds in reactants.

Submit when you are done. Highlight the reactants in lime. Highlight the products in aqua.

Exothermic reaction a type of reaction that releases energy. 2 Mg + O 2 → 2 MgO + energy(heat) energy/heat on the right side of the arrow meaning its getting hotter or colder.

Endothermic reaction a type of reaction that absorbs energy. 2 Mg + O 2 + energy(heat) → 2 MgO energy/heat on the left side of the arrow meaning it needs energy to start the chemical reaction

Reaction Rate how fast or slow a reaction takes place; how fast reactants change to products. Five factors effect the rate of a reaction: 1.Concentration(amount) 2.Surface area 3.Catalyst 4.Inhibitor 5.Temperature

Activation Energy the energy needed to start a chemical reaction

Five factors effect the rate of a reaction: 1.Concentration(amount) of reactants- the more you have the slower the reaction rate. 2.Surface area of reactants- The smaller the space the reaction occurs in the faster the reaction rate 3. Catalyst- a chemical that is used to lower the activation energy, the energy needed to start a chemical reaction, and make the reaction occur faster 4. Inhibitor- a chemical that is used to increase the activation energy and make the reaction occur slower 5.Temperature- the higher the temperature the faster the reaction occurs.

Highlight the vocabulary from today’s notes, then make notecards Chemical formula Subscript Coefficient Chemical reaction Chemical equation Reactant Product Exothermic Reaction Endothermic Reaction Reaction Rate Activation Energy Catalyst Inhibitor