Presentation on theme: "TAUGHT BY LINDSEY COYLE AND HUNTER COLON CHEMICAL REACTIONS 7.1 Chemical reactions always involve changing substances the reactants change into one."— Presentation transcript:
CHEMICAL REACTIONS 7.1 Chemical reactions always involve changing substances the reactants change into one or more substances, or products. Reactants Products The bonds hold the atoms together but break and form again in a different way. This is the law of conservation of mass. Mass is neither created nor destroyed during the process
WRITING CHEMICAL EQUATIONS 7.2 In chemical equations an arrow separates the formulas of the reactants (on left) from the formula of the product (on right ) Ex: Fe+O 2 Fe 2 O 3 Skeleton Reaction- Chem equation that does not indicate the relative amounts of the reactants and products. Catalyst- A substance that speeds up a reaction without being used up Ex: H 2 O 2 (aq) MnO 2 H 2 O (l)+ O 2 (g) To Indicate the physical state (s) for solid, (l) for liquid, and (g) for gas, (aq) for substance dissolved in water.
You can write word equations similar to chemical equations for everyday processes. Ex: Forwards+Guards+Center Basketball Team F+G+C F 2 G 2 C (unbalanced) ^does not indicate the number of people needed for each position in the product. You need coefficients. Balanced Equation: F 2 + G 2 + C F 2 G 2 C
Make an equation for an average summer outfit! Hint: (flip flops (2), t-shirt, and shorts) If you guessed F + T + S FTS
Balancing Chem Equations 7.4 Balancing chem equations so its quantitatively correct. In balanced equations each side of the equation has the same number of atoms of each element. Atoms only rearranged.
5 Types Combination 7.6- two or more substances react to form a single substance Decomposition 7.7- a single compound is broken down into two or more products Decomposes into two simpler compounds. Requires energy from heat, light, or electricity.
Single-Replacement 7.8- Atoms of an element replace the atoms of a second element in a compound Double-Replacement 7.9- Involves an exchange of positive ions between two compounds Usually between two ionic compounds in an aqueous solution.
An element or compound reacts with oxygen often producing energy in the form of heat and light.
You must recognize the possible type of reaction that the reactants can undergo Remember! Combination=Combine chemically to form new compound. 2 elements, 2 compounds, at least one a molecular compound Decomposition=Decomposed into two or more elements or compounds. A single binary compound a single ternary compound Single-Replacement=element replaces another element from a compound aqueous solution. An element and a compound Double-Replacement=2 ionic compounds react by exchanging cations to form two different compounds. Combustion=Reaction with oxygen to produce carbon dioxide and water. Oxygen and a compound of C or H
*BALANCE THIS EQUATION AND IDENTIFY THE TYPE OF REACTION! ___ NaBr + ___ Ca (OH) 2 ___ CaBr2 +___NaOH A)2,1,1,2 Double Replacement2,1,1,2 Double Replacement B)1,2,3,1 Single Replacement1,2,3,1 Single Replacement C)1,2,1,3 Combination Reaction1,2,1,3 Combination Reaction D)3,4,2,1 Combustion Reaction3,4,2,1 Combustion Reaction
Write the word equations below as chemical equations and balance Zinc and lead (11) Hydrogen gas and nitrogen monoxide