1 mole = 602,000,000,000,000,000,000,000 n = 6.02 x things What if we had a mole of sugar cubes? How much space would we need to store them? We could cover the entire province with sugar…….. …to a depth of 911 kilometers!!!!! things 5.00 moles means that you Multiply 5.00 x (6.02 x )

On the other hand; if we place one mole of hydrogen atoms in our hand, they would weigh just over 1.0 gram !!!!!

Writing Equations from words Reactants are written on the left side of the equation. Products are written on the right side of the equation. Reactants and products are separated with an arrow. Symbols:→ means ‘to yield’ or ‘to produce’ or ‘forms” etc. + means ‘reacts with’ or ‘combines with’ or ‘and’ etc. (aq) means aqueous (in water) (s) means solid (l) means liquid (g) means gas Example: Propane reacts with oxygen gas to produce carbon dioxide gas and water vapor.

Remember to include the standard states of the elements. If we burn or oxidize or combust a substance, this means that we must add oxygen gas as a reactant. O 2 (g) If we burn a hydrocarbon ( a compound made from carbon and hydrogen atoms only), the products are always carbon dioxide and water. ( this applies to any C,H,O compound) The simplest hydrocarbons are: CH 4 (g) methane C 2 H 6 (g) ethane C 3 H 8 (g) propane C 4 H 10 (g) butane C 5 H 12 (g) pentane

To ‘heat’ a substance means that we warm or heat it up in order to make it react. If it is not burned – no oxygen gas is added. The term excess means that sufficient amounts of each reactant have been added so that the reaction can run to completion.

Reactants = Products

Balancing Chemical Equations The number of moles of each kind of atom in the reactants must be equal to the number of moles of each kind of atom in the products. The meaning of the equation cannot be changed. Equations are balanced by placing coefficients in front of each substance as required. There is an infinite number of ways to balance an equation. We want each equation to meet one of the following conditions. 1) One of the coefficients is fixed at a value of 1. 2) The coefficients do NOT have a whole number common factor.

Procedure: (Suggestions) Start with the largest, most complex materials. Leave pure elements until last. Try to fix the coefficient of one of the materials at 1. Do not erase coefficients. (ERASE ALL OR NONE) START!!!!!

Procedure for solving chemical equations 1. Always start with a balanced equation. 2. If necessary, convert the given value from the question into moles. (the given value is the one we are told about) 3. Write the partial equation. This is copied from the balanced equation. It shows the relationship between the given value and the unknown value. ( the unknown value is the one we are solving for) 4. Make the coefficient of the given value, in the partial equation equal to one. (divide both sides by the coefficient of the given value) 5. Substitute the given value, in moles, into the partial equation. (multiply both sides by the given value) 6. If necessary, convert the answer into the appropriate unit. This works every time!! (Better learn it)

Limited Reactants Problems This kind of problem is recognized by 2 given values in the question. It is solved in two steps: a) Determine which substance (which given value) controls (limits) the reaction. This is the one that we will run out of first. b) Solve the equation normally. (using the same steps as before)

An example: Given: H2 (g) + Cl2 (g)