STOICHIOMETRY

Smores: What is needed to make a good smore? ___ Graham Crackers ___ Chocolate Chips ___ Marshmallows

Formula for a good smore: What if I wanted to make 10 smores? What if I only had a pack of 30 graham crackers, how many smores could I make? What if I had 30 graham crackers and 12 marshmallows? How many could I make?

Hydrogen Moles Oxygen Water 2 50 1000 10 Hydrogen Gas reacts with Oxygen Gas to produce water (synthesis). Fill in the chart: Hydrogen Moles Oxygen Water 2 50 1000 10

The study of quantitative relationships between the amounts of reactants used and mounts of products formed by a chemical reaction is called STOICHIOMETRY

Stoichiometry is based on the LAW OF CONSERVATION OF MASS:

Relationships Derived from a Balanced Chemical Equation 4 Fe (s) + 3O2 (g) --> 2Fe2O3 (s) Iron + 4 atoms Fe + 4 mol Fe + 223.4 g Fe + 319.4 g reacts --> Fill in the Chart and Show your Work

Example: The combustion of propane (Tricarbon Octahydride) provides energy for heating homes, cooking food, and soldering metal parts. Interpret the equation for the combustion of propane in terms of representative particles, moles, and mass. Show that the law of conservation of mass is conserved (orange 370).

PRACTICE: Interpret the following balanced equations in terms of particles, moles, and mass. Show that the law of conservation of mass is conserved. a. Nitrogen gas reacts with hydrogen gas to produce gaseous nitrogen tryhydride molecules. b. Hydrochloric Acid (HCl) reacts with potassium hydroxide in a double replacement reaction c. Solid magnesium reacts with oxygen gas in a synthesis reaction. d. Sodium solid reacts with liquid water to produce aqueous sodium hydroxide and hydrogen gas e. Solid zinc reacts with HNO3 (aqueous) to produce zinc nitrate (aqueous), gaseous dinitrogen monoxide, and liquid water.

MOLE RATIOS!

You should know by now that the coefficients in a chemical equation indicate the relationships between moles of reactants and products.

A mole ratio is a ratio between the numbers of moles of any two of the substances in a balanced equation.

For example, consider the following reaction: 2K (s) + Br2 (l) --> 2KBr (s) What mole ratios can be written in this reaction? List all 6:

Determine all possible mole ratios for the following balanced chemical equations: a. 4Al(s) + 3O2 (g) --> 2Al2O3 (s) b. 3Fe (s) + 4H2O (l) --> Fe3O4 (s) + 4H2 (g) c. 2HgO (s) --> 2Hg (l) + O2 (g) d. Zinc oxide (solid) reacts with aqueous hydrochloric acid (HCl) to produce zinc chloride (aq) and liquid water e. Butane (C4H10) and oxygen go through complete combustion

ALWAYS BALANCE THE EQUATIONS FIRST WHEN YOU ARE WORKING WITH THESE PROBLEMS. IF THAT FAILS, THE WHOLE QUESTION WILL BE WRONG.

One disadvantage of burning propane (C3H8) is that carbon dioxide is on eof the products. How many moles of carbon dioxide are produced when 10.0 mol of propane are burned in excess oxygen in a gas grill?

You try: 1. Methane (CH4) and sulfur (S8) react to produce carbon disulfide and Hydrosulfuric Acid (H2S). Balance the equation, calculate the moles of CS2 produced when 1.50 mol of S8 are used, and then find out how many moles of H2S are produced.

2. Sulfuric Acid (H2SO4) is formed when sulfur dioxide reacts with oxygen and water. How many moles of sulfuric acid AND oxygen will there be if there are 12.5 moles of sulfur dioxide?

Black Chemistry 11 Book: Page 319 (1,2,3)