AP Chemistry Unit 4 - Chemical Reactions | Kentucky State University

University:
Kentucky State University
Course:
CHE 101 | General Chemistry I
Academic year:

2022
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217

Pages:

2
Author:

yisihogo4aq

Unit 4 - Chemical Reactions How to write Net ionic equations: ● Start with molecular equation ● Make the transition to the complete ionic equation ● Cross off spectator ions Here’s an example: Titration - experiment to calculate moles/concentration of a chemical ● Titrant is slowly dripped to the analyte until exactly enough titrant is added to react with all of the analyte(equivalence point) ● 𝑀1 𝑉1 = 𝑀2 𝑉2 if acid and base are in a 1-to-1 mole ratio Conjugate acid has one more hydrogen than a conjugate base in a Bronsted-Lowry conjugate acid-base pair ● Acid donates a proton(H+) and base accepts the proton(H+) Oxidation-reduction reactions involve the gain and loss of electrons ● Mnemonic device - LEO(loss of electrons is oxidation) the lion says GER(gain of electrons is reduction) ● Oxidation numbers represent how many electrons an atom has. They should be used to confirm oxidation-reduction reactions. ○ Single elements have an oxidation number of 0 ○ Single ions have the same oxidation number as their charge ○ Halogens are usually -1 ○ Hydrogen can be +1(bonded to nonmetals) or -1(bonded to metals) ○ Oxygen is usually -2 ○ The sum of all oxidation numbers in a neutral compound is zero. The sum of all oxidation numbers in an ion is its charge. ● Balancing oxidation-reduction reactions ○ Write the balanced half reactions(a single element gaining or losing electrons) ○ Count the number of oxygens and balance the equation by adding the same number of waters ○ Balance the extra hydrogens from the water by adding H+ ○ Balance the charge from the extra hydrogens by adding electrons ○ Multiply reactions so the number of electrons matches and combine half reactions Precipitation reactions - two ionic compounds combine to form a solid in an aqueous solution