Section 13: Reactions
Section 13A: Chemical Equations
Skeleton Equations, Word Equations, Balancing Reactions
While discussing different reactions, it is important that the vocabulary is understood. Chemistry has its own language when it comes to describing what occurs when two different substances interact. When two substances interact, what is exactly happening? There is a rearrangement of the atoms within each of the substances. This is the mark of a chemical reaction. The Law of Conservation of Mass dictates that the total mass of substances the react will equal the total mass of the products. To make sure that this occurs, each reaction when written out needs to be balanced.
While discussing different reactions, it is important that the vocabulary is understood. Chemistry has its own language when it comes to describing what occurs when two different substances interact. When two substances interact, what is exactly happening? There is a rearrangement of the atoms within each of the substances. This is the mark of a chemical reaction. The Law of Conservation of Mass dictates that the total mass of substances the react will equal the total mass of the products. To make sure that this occurs, each reaction when written out needs to be balanced.
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The video to the left is a Khan Academy video that goes over balancing chemical equations. It does a good job of explaining how to get the correct coefficients for each part of a chemical reaction.
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Section 13B: Stoichiometry
Mole Ratios, Gas Ratios, Mass-to-Mass Conversions, Limiting Reagents, Percent Yield
As reactions occur, the amount of products that should be created must be calculated. If a reaction is worthy of study, then is should be determined how much reactant is needed to make a given amount of a product. Stoichiometry is the study quantities in reactions. Although it seems like a strange thing to look at in a reaction, it is vital for companies looking to produce different compounds. When performing a reaction it is possible that one of the reactants will be in excess, in other words one reactant will run out before the other. The reactant that runs out first is called the limiting reagent.
As reactions occur, the amount of products that should be created must be calculated. If a reaction is worthy of study, then is should be determined how much reactant is needed to make a given amount of a product. Stoichiometry is the study quantities in reactions. Although it seems like a strange thing to look at in a reaction, it is vital for companies looking to produce different compounds. When performing a reaction it is possible that one of the reactants will be in excess, in other words one reactant will run out before the other. The reactant that runs out first is called the limiting reagent.
Practice
Section 13C: Solutions
Solution Stoichiometry
Many of the reactions that take place in chemistry occur in the solution phase. While performing calculations with these types of reaction, molarity must be fully understood. When solutions are mixed, the volume plays a minor role, the number of moles of a reactant is what dictates that amount of product that is made.
Many of the reactions that take place in chemistry occur in the solution phase. While performing calculations with these types of reaction, molarity must be fully understood. When solutions are mixed, the volume plays a minor role, the number of moles of a reactant is what dictates that amount of product that is made.