Chemistry Flashcards
Solvent
substance that dissolves the solute
Solute
substance that gets dissolved
The more solute there is per solvent, the more __________ the solution gets
concentrated
Base Units: n, V, C
How to find each?
n = mol
V = L (if in mL, divide by 1000 to convert to L)
C = mol/L
to find C, divide ‘n’ (number of mols) by ‘V’ (volume)
to find V, divide ‘n’ by ‘C’ (concentration)
to find n, multiply ‘c’ by ‘v’
C1V1 = C2V2 Steps to solving:
- Identify all info given as C1, V1, C2, or V2 then realize what variable you’re looking for
- Re-arrange equation to isolate the variable you’re solving for
- Do the math and solve
Remember base units, C = mol/L and V = L, therefore convert from mL to L if needed
TRENDS IN THE PERIODIC TABLE
IONIZATION
the amount of energy required to remove an electron from an atom/molecule
increases going up, and to the right of the periodic table
the lower the pH (more acidic a solution is), the higher the ionization energy
–> Noble gases has highest
ELECTRON AFFINITY
the amount of energy given off after an atom/molecule acquires an electron
increases going up and to the right of the periodic table
the lower the pH (more acidic a solution is), the higher the electron affinity
–> hallogens has highest
ELECTRONEGATIVITY
the ability of an atom/molecule to attract other electrons
increases going up and to the right of the periodic table
the lower the pH (more acidic a solution is), the higher the electronegativity
–> hallogens
ATOMIC RADIUS
the distance from an atom’s nucleus to the outermost orbital of electron
increases going down and to the left of the periodic table
the lower the pH (more acidic a solution is), the higher the atomic radius
–> alkali metals
BALANCING EQUATIONS
reactants are listed on the _____ side of the arrow
products are on the _____ side of the arrow
reactants are listed on the left side of the arrow
products are on the right side of the arrow
DECOMPOSITION REACTION
AB –> A + B
SYNTHESIS (COMBINATION)
A + B –> AB
SINGLE REPLACEMENT
AB + C –> B + AC
DOUBLE REPLACEMENT
AB + CD –> AC + BD
COMBUSTION
CxHy, + O2 –> CO2 + H2O
STEPS TO BALANCE EQUATION:
1) Make a T chart with reactants (R) on one side and products (P) on the other
2) Write how many atoms each individual element has on the reactants side
3) If the number of atoms of an element on the product side doesn’t match the reactants side, you must add a coefficient in front of that element on the products side (so that coefficient multiplied by the number of atoms the element has will equal the number of atoms the element has on the reactants side
4) NOTE: if an element has a negative number of atoms on the products side, you may have to multiply all the coefficients by an even number such as 2
NOTE: if there are brackets in the equation, you multiply the outside bracket number by the inside bracket number (if there isn’t an inside bracket number, assume it is 1
Valence shells (completing the outer shell)
2
8
8
18
18
32
32
Periodic table:
1) groups and 2) periods
Which is vertical columns and which is horizontal rows
groups = vertical columns
periods = horizontal rows
What is the name of group 1 (excluding hydrogen) on the periodic table
Alkali metals
What is the name of group 2 on the periodic table
Alkaline earth metals
What is the name of group 4 -12 on the periodic table
Transition metals
What is the name of group 18 on the periodic table
Noble gases
What is the name of group 17 on the periodic table
Halogens
What is the name of the group H, C, N, O, P, S, Se on the periodic table
Non-metals
What is the name of the group B, Si, Ge, As, Sb, Te, Bi, Po on the periodic table
Metalloids
ionic
One atom donates an electron to another atom
This can only be done between metals and non metal.
covalent
Two or more atoms SHARE electrons EQUALLY
This can only be done between two non metals or two metals and a metalloid.
density equation
density = mass/volume
Isotopes
Same number of protons, but different number of neutrons
Calculating moles formulas
In the triangle in spots 1) top 2) bottom left, 3) bottom right
1.
1) n 2) c 3) v
n = c x v
- 1) m 2) n 3) M
n = m/M
Neutralization reaction
when an acid and a base react to make a salt and water
Ex:
Acid + Base –> Salt + Water
HCl + NaOH –> NaCl + H2O
pH scale
0 (acidic) —– 7 (neutral —-> 14 (basic)
HCl (0), Orange juice (3), Blood/water (7), Household cleaners (13), NaOH (14)
Arrhenius theory
Acid: substance that produces H+ in
water
Base: substance that produces OH in
aqueous solution
strong vs weak acids and bases
Strong acids completely dissociate into ions in water, while weak acids only partially dissociate
Strong Acids:
HCl
HBr
HI
H2SO4
Strong Bases:
NaOH
LiOH
KOHCa(OH)2
Gas laws
1) Boyle’s Law - pressure & volume - P1V1 = P2V2
2) Charles’ Law - volume & temp - V1/T1 = V2/V2
3) Avagadro’s Law - volume & moles - V1/n1 = V2/n2
4) Ideal Gas Law = PV = nRT
A gas has an initial pressure of 5.85 atm and an initial volume of 3.65 L. What is the new volume of the gas if the pressure drops to 3.00 atm. Assume temperature and the number of moles are kept constant.
V2 = 7.12L
A sample of H2 gas occupies a volume of 8.56 L at a temperature of 0°C and a pressure of 1.5 atm. How many moles of hydrogen are present?
n = 0.57 mol H2
Calculate the volume of 0.845 mol of nitrogen gas at a pressure of 0.9200 atm and a temperature of 315 K.
➞ given:
n = 0.845 mol N2
T = 315 K
V = ?
P = 0.9200 atm
➞ PV = nRT ➞ V = nRT / P
➞ V = nRT / P = (0.845)(0.0821)(315) / 0.9200 = 23.8 L N2
A sample of methane gas with a volume of 38 mL at 5°C is heated to 86°C at constant pressure. Calculate its new volume.
V1 = 38 mL , T1 = 5 + 273 = 278 K
➞ V2 = ?? mL , T2 = 86 + 273 = 359 K
V2 = 49mL
How to tell if something is polar or non polar?
1) Has to meet 2 criteria:
1. the molecular shape around the central atom has no lone pairs, or if it does its either square planar (4 atoms, 2 lone pairs) or linear (2 atoms and 3 or 4 lone pairs)
2. All atoms around the central atom are the same
2) Draw the lewis dot diagram to tell if these apply
if meets criteria then its non polar
Ex: CH4, NH3, CO2
Identify each as polar or non polar:
CH4
NH3
CO2
CH2Cl2
CH4 - non polar
NH3 - polar
CO2 - non polar
CH2Cl2 - polar
Electron configuration
1) Find out how many electrons are in the element (the proton number)
2) Use electron configuration chart (draw out) to figure out
1s
2s2p
3s3p3d
4s4p4d4f
5s5p5d5f
6s6p6d
7s7p
8s
–> s holds 2 valence electrons
–> p holds 4 valence electrons
–> d holds 10 valence electrons
Ex: Boron
1) has 5 valence electrons
2) 1s^22s^22p^1
–> the little numbers shows how many spots you are using in each shell
1s^2 =2 , 2s^2 = 2, 2p^1 = 1
2 + 2 + 1 = 5 (number of electrons)
Calculate the enthalpy for 2C + H2 –> C2H2
Given:
C2H2 + 5/2 O2 –> 2 CO2 + H2O triangleH = -1299.5kJ/mol
C + O2 —> CO2 triangleH = -393.5kJ/mol
H2 + 1/2O2 –> H2O triangleH = -285.8 kJ/mol
https://www.youtube.com/watch?app=desktop&v=Z4ntAj7GcIo
1) Notice C2H2 is on the wrong side so flip that reaction
H2O + 2CO2 –> 5/2O2 + C2H2 =1299.5kJ/mol (now positive)
2) Notice there is 2 C needed so multiply second reacton by 2
2C + 2O2 –> 2 CO2 = -787kJ/mol (x2 original)
3) Start cancelling out things on opposite sides of the arrows and add up enthalpies
H2O + 2CO2 –> 5/2O2 + C2H2 =1299.5kJ/mol
2C + 2O2 –> 2 CO2 = -787kJ/mol
H2 + 1/2O2 –> H2O = -285.8 kJ/mol
—————————————————————-
2C + H2 –> C2H2 = 226.7kJ/mol
