Unit 6 (chapters 5 & 6)

Question 1

acid

Answer 1

Substances that produce hydrogen ions in aqueous solution; proton donor

Question 2

activity series

Answer 2

lists the elements from most reactive to least reactive
ex: Halogens activity series is F>Cl>Br>I

Question 3

aqueous

Answer 3

dissolved in water

Question 4

balancing

Answer 4

Making sure that all atoms present in the reactants are accounted for among the products

Question 5

binary compound

Answer 5

A two-element compound

Question 6

coefficient

Answer 6

Large number before particles, affects all atoms in particle

Question 7

combustion

Answer 7

• Burning
• One of the reactants is always O2 (because O2 is necessary to support combustion)
• The other reactant is the thing being combusted- all atoms in that reactant are separated from each other and combined with oxygen
• Every product is a binary compound with oxygen in it
• The most common combustion reactions involve hydrocarbons (compounds of C & H)
  Ex: 2C8H18 (g) + 25O2 (g) -> 16CO2 (g) + 18H2O

Question 8

decomposition

Answer 8

• AB -> A + B
• a compound breaks down into two or more simpler compounds or elements
• Only ONE reactant and it is always a compound (elements cannot decompose)
  Ex: 2H2O2 (aq) -> 2H2O2 (l) + O2 (g)
  Ex: 2NaCl (s) -> 2Na (s) + Cl2 (g) (this requires electrolysis)

Question 9

dissociation

Answer 9

• NOT a reaction type- only physical change (though similar to decomposition)
• ionic compound dissolves (physical change)
• starts with single compound and ends with multiple separated parts, but they aren’t neutral elements and compounds, but instead aqueous ions
  Ex: NaCl (s) -> Na+ (aq) + Cl- (aq)

Question 10

double replacement

Answer 10

• AB + CD -> AD + CB
• A reaction between two ionic compounds
• The cation and anion in each switch places (or trade partners)
  Ex: AlCl3 (aq) + 3AgNO3 (aq) -> 3AgCl (s) + Al(NO3)3 (aq)

Question 11

endothermic

Answer 11

heat taken out, feels cold

Question 12

exothermic

Answer 12

exo=exit, thermic=thermomator
heat given out, will be felt- feels warm

Question 13

formula

Answer 13

chemical equation of an element or compound

Question 14

formula unit

Answer 14

the chemical formula of an ionic compound that lists the ions in the lowest ratio that equals a neutral electrical charge

Question 15

ion

Answer 15

An atom or a group of atoms that has a net positive or negative charge

Question 16

ionic compound

Answer 16

A compound that results when a metal reacts with a nonmetal to form cations and anions

Question 17

metal

Answer 17

Elements that give up electrons relatively easily and are typically lustrous, malleable, and good conductors of heat and electricity

Question 18

molecular compound

Answer 18

compound with 2 or more nonmetals

Question 19

molecule

Answer 19

a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Question 20

monoatomic ion

Answer 20

ion consisting of only one atom

Question 21

nonmental

Answer 21

Elements that do not exhibit metallic characteristics. Chemically, a typical nonmetal accepts electrons from a metal

Question 22

polyatomic ion

Answer 22

An ion containing a number of atoms

Question 23

precipitate

Answer 23

production of insoluble solid from liquids

Question 24

product

Answer 24

end result of reactant, right side of the equation

Question 25

reactant

Answer 25

materials on the left side of the equation, what you start with

Question 26

reaction

Answer 26

a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products

Question 27

single replacement

Answer 27

• A + BC -> AC + B
• A + BC -> BA + C
• Reactants are always a lone element and a compound
• The lone element in the reactants replaces one of the elements in the compound
• A nonmetal can only replace another nonmetal (taking the anion role in the compound)
• A metal can only replace another metal (taking the cation role in the compound)
  -exception to this is metals can also replace H+ in acids
  Ex: Zn (s) + 2HCl (aq) -> ZnCl2 (aq) + H2 (g)
  Ex: Cl2 (g) + 2KBr (aq) -> 2KCl (aq) + Br2 (l)
  Note: not all single replacement reactions can occur
  An element can only replace another element that is below it in an activity series (more reactive elements can replace less reactive elements)

Question 28

subscript

Answer 28

lower than an atom, shows the number of only that specific atom

Question 29

symbol

Answer 29

a notation of one or two letters representing a chemical element

Question 30

synthesis

Answer 30

• A + B -> AB
• Combination of two or more elements or compounds to make a larger compound
• only ONE product and it is ALWAYS a compound
  Ex: N2 (g) + 3H2 (g) -> 2NH3 (g)
  Ex: 2Mg (s) + O2 (g) -> 2MgO (s)
  Note: the second example can be classified as a combustion reaction. Combustion and Synthesis are the only reaction overlaps

Question 31

transition metal

Answer 31

metallic elements in the middle block of periodic table, variable valence. Valence electrons in 2 shells instead of 1

Question 32

chemical reactions

Answer 32

aka chemical changes, most often referred to as “reactions”
there’s no such thing as physical reactions
no new matter

Question 33

Signs of chemical reactions

Answer 33

Color change (does not count if it’s expected, such as with food dye)
Enegry released or absorbed (endothermic, exothermic, light)
Precipitate formed (freezing doesn’t count, usually 2 clear solutions results in nonclear solution)
Gas given off

Question 34

Energy

Answer 34

the ability to do work or cause change in matter

Question 35

Potential energy

Answer 35

energy of position or arrangement of particles

Question 36

Kinetic energy

Answer 36

energy of motion

Question 37

triangle above arrow in equation

Answer 37

indicates reactants are heated

Question 38

Balancing equations rules

Answer 38

• Use pencil
• Write the reactants on the left and the products on the right, separated by a right-pointing arrow ->
• Double-check formulas and leave them alone, no changes!
• Start with elements other than hydrogen and oxygen (because they’re so common)
• Make the number of each kind of atom equal by adding coefficients
• Coefficient * subscript = # of that atom

Question 39

Balancing equation tips

Answer 39

• When balancing an equation with polyatomic ions in the formula, you can treat the polyatomic ion as one big particle and not balance the elements individually
• If it doesn’t work at first, add 1 to the coefficient before the first particle on the reactant side, the solve. Continue as needed