4.3 Reaction Stoichiometry

• The equation is balanced after a final check of atom and charge balance.

• H2O is produced by hydrogen peroxide in acidic solution.
• A balanced equation is needed for this reaction.

• By the end of this section, you will be able to: Chemical formulas give the identities of the reactants and products involved in the chemical change.
• A quantitative assessment of the relationships between the amounts of substances consumed and produced by the reaction can be made using coefficients.
• The use of balanced chemical equations is explored in this module.

• The way people go about many activities is similar to the way the general approach is used.
• Food preparation can offer an appropriate comparison.
• A recipe for eight pancakes calls for 1 cup pancake mix, 34 cup milk, and one egg.

• If two dozen pancakes are needed for a big family breakfast, the ingredient amounts must be increased proportionally according to the recipe.
• Balanced chemical equations are used to determine the amount of one reactant required to react with a given amount of another reactant, or to yield a given amount.

• The number of ammonia molecule produced from a given number of hydrogen molecule or the number of hydrogen molecule required to produce a given number of ammonia molecule can be calculated using these factors.
• Similar factors can be derived for any pair of substances.

• There is a reaction to produce aluminum iodide.
• The heat of the reaction causes some of the solid iodine to be purple.

• The two substances of interest are 3 mol I2 2 mol Al.

• The approach is the same, though the number of moles of the molecule is not requested.
• The moles-to-numbers conversion factor will be used.

• The amount of substances involved in a chemical reaction may be related to these examples.
• It's not easy to directly measure the numbers of atoms and molecules, and the more readily measured property of mass is required in the practical application of stoichiometry.

• Additional steps of the sort learned in the previous chapter are required in this case.

• The approach required here is the same as for the different approach only that the provided and requested mass are for reactant species.

• These examples show a few instances of calculation.
• Depending on what quantities are provided and sought, there are many variations on the beginning and ending computational steps.
• Regardless of the details, all of these calculations share a common essential component.

• Computational steps are depicted in the flowchart.

• Since the 1990s, most automobiles have safety features such as absorbers.
• When a vehicle is involved in a collision, an appropriate amount of gas needs to be quickly inflated to the correct level.
• The requirement is satisfied through the use of explosives and the decomposition of NaN3 is a common choice.