CHEMICAL REACTIONS

Question 1

involve CHANGE in the IDENTITY and MOLECULAR COMPOSITION of the substance

Answer 1

CHEMICAL REACTION

Question 2

________ are the starting substance of a chemical raection

Answer 2

REACTANTS

Question 3

______ show what happens in a chemical reaction. they also show which elements, compounds, and molecules are involved
- shows the physical state of the reactants and products
- shows the number of reactants and products involved

Answer 3

CHEMICAL EQUATIONS

Question 4

reactants are written on the ____ side

Answer 4

left-hand

Question 5

products are written in ____ side

Answer 5

right-hand

Question 6

the product formation is denoted by _____

Answer 6

arrow symbol

Question 7

____ lower the energy needed for a reaction to occur but retain their chemical identities
- reactions that occur at high temperatures and pressures may require a ______
______ are not written on either side of the chemical equation rather, they are written as part of the reaction conditions

Answer 7

CATALYSTS

Question 8

reactants combine to form ONE PRODUCT
example: rusting of iron
(A + B → C)

Answer 8

SYNTHESIS OR COMBINATION REACTION

Question 9

• a reaction in which a compound BREAKS DOWN into TWO OR MORE simpler substance
• OPPOSITE of synthesis/combination reaction
  example: carbonated decomposing into oxides
  (A → B + C)

Answer 9

DECOMPOSITION REACTION

Question 10

• A reaction in which one element is SUBSTITUTED for another element in a compound
• the reactants are ALWAYS A PURE ELEMENT and a COMPOUND
• this will yield into a new compound or a different pure element
  example: formation of green forsterite mineral from dark-brown fayalite
  (A + BC → AB + C)

Answer 10

SINGLE-DISPLACEMENT OR SUBTITUTION REACTION

Question 11

• this type of reaction is COMMON between many IONIC COMPOUNDS
• a type of chemical reaction that occurs when TWO REACTANTS EXCHANGE CATIONS OR ANIONS yield two new products
  example: formation of sodium nitrate and silver chloride from silver nitrate and sodium chloride
  (AB + CD → AC + BD)

Answer 11

DOUBLE-DISPLACEMENT OR METATHESIS REACTION

Question 12

• Double-displacement reactions that occur between ACIDS AND BASES
  example: formation of sodium chloride from sodium hydroxide and hydrochloric acid
  (acid + base → salt + water)

Answer 12

ACID-BASE REACTION

Question 13

• a chemical reaction occurring in an AQUEOUS SOLUTION where TWO IONIC BONDS COMBINE, resulting in the formation of a substance insoluble in water
• these insoluble substances are residues more commonly known as precipitates

Answer 13

PRECIPITATION REACTION

Question 14

insoluble substances are residues more commonly known as

Answer 14

precipitates

Question 15

• atoms may LOSE OR GAIN their outermost electron in the process of reaction. when the number of electrons in atom changes, a redox reaction is said to occur

Answer 15

REDUCTION-OXIDATION OR REDOX REACTION

Question 16

• this occurs when the number of electrons in an atom changes
• these are also characterized by changes in charge because electrons transfer between elements involved

Answer 16

REDOX REACTIONS

Question 17

reduction means

Answer 17

electron gain

Question 18

oxidation means

Answer 18

electron loss

Question 19

this type of reaction involves the BURNING OF COMPOUNDS in the presence of OXYGEN
(hydrocarbon + oxygen → carbon dioxide + water)

Answer 19

COMBUSTION REACTION

Question 20

_____ is the number written in front of atoms, ions, and molecules in a chemical reaction

Answer 20

STOICHIOMETRIC COEFFICIENT