Ch. 11 Chemical EquationsCh. 11 Chemical Equations

Chemical reaction - One or more reactants change into one or more products

(atoms rearrange their attachments = new substances)

Chemical evidence - (Ch. 2) Bubbles, precipitate, change of temp, change in color

Reactants - A substance present at the start of a reaction

Products - A substance generated in a chemical reaction

Evidence of a Chemical ChangeEvidence of a Chemical ChangeChemical Change the particles in a compound break apart from their current chemical attachments (bonds) and rearrange to form new attachments. Either to new and different elements or in new amounts of attachments.

Bubbles - (baking soda in vinegar, or bubbles in electrolysis)

Change in temperature - (heat given off in a burning reaction)

Formation of a precipitate - (our lab example)

Sometimes changes in appearance - color, sound, texture, rot

KC 7 = Write the names of the reactants to the left of a yields arrow separated by “+” signs; then write the names of the products to the right of the arrow also separated by “+” signs

What is “cumbersome” (difficult) about a word equation?So many words to express what can ver y simple thing

when using symbols and formulas (like a shorthand)

Chemical equation = A representation of a chemical reactionNot to be confused with a Chemical Reaction

KC 8 Skeleton equation = write the reactant and product formulasA chemical equation that doesn’t indicate the relative amounts of the reactants and products (no numbers in front)

Descriptor (Equation Symbol)Similar to adjectives in English, they are extra symbols to enhance the detail in describing a chemical equation

Coefficient - Small whole numbers that are placed in front of formulas in an equation in order to balance it

Balanced equation - Each side of the equation has the same number of atoms of each element and mass is conserved

Bonds are rearranged

Chemical ReactivityChemical Reactivity

2H2(g) + O2(g) 2H2O(g)

Law of Conservation of Mass = the masses have to add up, nothing is created or destroyed, what goes in must come out

KC 22 Combination (or Synthesis) Decomposition Single replacement Double replacement Combustion