Chemical Reactions and pH
Chemical Reactions:
Chemical reactions are processes that change, or transform one set of chemicals into another. Chemical reactions have two parts, reactants and products. Reactants are the chemical compounds that enter into a chemical reaction, and products are the resulting chemical compounds. In chemical reactions, the mass and energy contained in the first set of chemicals is always transferred meaning the the products will have the same amount of mass and energy as the reactants.
A + B -------> AB Reactants Product(s) 2A + B -------> A + AB |
How do energy changes affect whether a chemical reaction will occur?
Chemical reactions either release or absorb energy when they occur. Changes in energy are one of the most important factors in determining whether a chemical reaction will occur. Chemical reactions that release energy often occur spontaneously, while chemical reactions that absorb energy will not occur without a source of energy. Chemical reactions that do not occur spontaneously require a certain amount of energy in order for the reaction to occur. This required energy is call activation energy.
Enzymes:
Catalysts are any substance that speeds up the rate of a chemical reaction. Enzymes are proteins that act as biological catalysts, speeding up the chemical reactions that take place in cells. Enzymes speed up chemical reactions by providing a place for the reactants to interact. Without enzymes, reactants just move around randomly until it collides with another reactant with enough force to break and create bonds between the two reactants. Enzymes seek out the reactants and place them together so that the reaction can occur at a faster rate.
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Acids, Bases, and pH:
Water molecules will sometimes split to create two ions, a hydrogen ion and a hydroxide ion.
The hydrogen ions have a positive charge and the hydroxide ions have a negative charge. The relative concentrations of hydrogen and hydroxide ions in solutions determine whether the solution is acidic or basic. Pure water contains equal concentrations of hydrogen and hydroxide ions which makes water neutral, or neither acidic or basic. When a solution has a higher concentration of hydrogen ions than hydroxide ions, the solution is acidic. When a solution contains a higher concentration of hydroxide ions than hydrogen ions, the solution is basic.
pH Scale:The pH scale is used to measure the relative acidity or basicity of different solutions. The scale ranges from 0 to 14. Acidic solutions have a pH of less than 7, while basic solutions have a pH of greater than 7. Solutions with a pH equal to 7 are said to be neutral.
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