Unit 4 Review - Chemistry A

Unit 4 review
chemistry - semester a

unit 4 - Chemical reaction & stoichiometry

• A polyatomic anion that contains an oxygen = oxyanion

• An acid that contains hydrogen, oxygen, and a third element (usually a nonmetal) = oxyacid

• Ionic compound composed of a cation from a base bonded to an anion produced by an acid = salt

unit 4 - Chemical reaction & stoichiometry

• Oxidation numbers = assigned to an element to indicate the number of electrons that might be lost, gained, or shared by an atom when it bonds with an ion or an atom of another element to form a compound

• A catalyst is a substance that alters the RATE of the reaction but is not consumed during the reaction

• A precipitate is a SOLID substance that settles out of an aqueous solution as a result of a reaction between aqueous solutions

unit 4

unit 4 - Chemical reaction & stoichiometry

• Balance the equation

  Al_(s) + NiSO_4(aq) → Al₂(SO₄)_3(aq) + Ni_(s)

  2Al_(s) + 3NiSO_4(aq) → Al₂(SO₄)_3(aq) + 3Ni_(s)

• _{Single-Replacement Reaction}

unit 4 - Chemical reaction & stoichiometry

• Balance the equation

  Na₂O_(s) + H₂O_(l) → NaOH_(aq)

  Na₂O_(s) + H₂O_(l) → 2NaOH_(aq)

• _{Synthesis Reaction}

unit 4 - Chemical reaction & stoichiometry

• The percentage by mass of each element in a compound = percent composition

• Empirical formula is a symbolic representation of a chemical compound that uses element symbols and subscripts to indicate the smallest whole-number ratio of each kind of atom in a chemical compound

unit 4 - Chemical reaction & stoichiometry

• Reaction Stoichiometry - study of the relationships between the quantities of reactants and products involved in chemical reactions

• Limiting reactant = compound/element used up in a chemical reaction that causes the reaction to stop

• Excess reactant = reactant that is NOT completely used up in a chemical reaction

• Mole ratio = conversion factor that compares the number of moles of one substance to the number of moles of another

unit 4 - Chemical reaction & stoichiometry

• Actual yield = measured quantity that is actually obtained from chemical reaction

• Theoretical yield = max amount of product that COULD BE OBTAINED in a chemical reaction under ideal conditions

• Percentage yield = difference between the actual and theoretical expressed as percentage

Multiple Choice

Have you completed the Unit 4 Review?

Do not forget to complete the Unit 4 Test in BrightThinker

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