Unit 6 (chapters 5 & 6) Flashcards
acid
Substances that produce hydrogen ions in aqueous solution; proton donor
activity series
lists the elements from most reactive to least reactive
ex: Halogens activity series is F>Cl>Br>I
aqueous
dissolved in water
balancing
Making sure that all atoms present in the reactants are accounted for among the products
binary compound
A two-element compound
coefficient
Large number before particles, affects all atoms in particle
combustion
- 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
decomposition
- 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)
dissociation
- 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)
double replacement
- 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)
endothermic
heat taken out, feels cold
exothermic
exo=exit, thermic=thermomator
heat given out, will be felt- feels warm
formula
chemical equation of an element or compound
formula unit
the chemical formula of an ionic compound that lists the ions in the lowest ratio that equals a neutral electrical charge
ion
An atom or a group of atoms that has a net positive or negative charge
ionic compound
A compound that results when a metal reacts with a nonmetal to form cations and anions
metal
Elements that give up electrons relatively easily and are typically lustrous, malleable, and good conductors of heat and electricity
molecular compound
compound with 2 or more nonmetals
molecule
a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
monoatomic ion
ion consisting of only one atom
nonmental
Elements that do not exhibit metallic characteristics. Chemically, a typical nonmetal accepts electrons from a metal
polyatomic ion
An ion containing a number of atoms
precipitate
production of insoluble solid from liquids
product
end result of reactant, right side of the equation
reactant
materials on the left side of the equation, what you start with
reaction
a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products
single replacement
- 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)
subscript
lower than an atom, shows the number of only that specific atom
symbol
a notation of one or two letters representing a chemical element
synthesis
- 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
transition metal
metallic elements in the middle block of periodic table, variable valence. Valence electrons in 2 shells instead of 1
chemical reactions
aka chemical changes, most often referred to as “reactions”
there’s no such thing as physical reactions
no new matter
Signs of chemical reactions
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
Energy
the ability to do work or cause change in matter
Potential energy
energy of position or arrangement of particles
Kinetic energy
energy of motion
triangle above arrow in equation
indicates reactants are heated
Balancing equations rules
- 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
Balancing equation tips
- 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
