Dimensional Analysis
2000.0 μL → mL?
2.0000 mL
What's the difference between empirical and molecular formulas?
Empirical = simplest whole-number ratio of atoms in a compound (EX: CH₂O for glucose)
Molecular = the exact number of atoms of each element in a molecule (EX: C₆H₁₂O₆ for glucose)
Explain how to name: a) ionic compounds and b) molecular compounds.
a) Write the element name of the cation (metal) first.
If the metal is a transition metal, a roman numeral is required to indicate the charge.
This is followed by the anion (non-metal) element name, ending in “-ide”.
b) First, write the element name of first element in the bond. If there is more than one ion, add the corresponding prefix to the beginning of the word.
Then, for the second element, begin the name with the prefix corresponding to the number of ions for that element and end the word with “-ide”.
Define: a) Proton, b) Neutron, c) Electron
a) Located in center; particle of positive electric charge
b) Located in center; particle of neutral charge
c) Located in electron cloud; particle of negative charge
Name the following polyatomic ions based on the formula:𝑁𝑂2-, 𝑁𝑂3-, 𝑃𝑂43-, 𝐻𝑃𝑂42-, 𝐻2𝑃𝑂4-
𝑁𝑂2- = Nitrite ion
𝑁𝑂3- = Nitrate ion
𝑃𝑂43- = Phosphate ion
𝐻𝑃𝑂42- = Hydrogen Phosphate ion
𝐻2𝑃𝑂4- = Dihydrogen Phosphate ion
850 m/s → mi/hr? (Conversion factor: 1 mi = 1.609 km)
1901.8 mi/hr
List the steps to determining the empirical formula when given percent composition and the molar mass of a compound.
1. Divide percentages (in grams) by the molar mass of their respective elements to get the mole values of each element.
2. Divide all mole values by the element with the smallest value (this should give you a whole number).
If it does NOT give you a whole number, the following must be done: a) if number ends in "0.5", multiply all mole values by '2', b) if number ends in "0.3" mulitply all mole values by '3'
3. Once whole number mole values acquired, these will be subscripts to the symbols in the formula.
Write the formula from the name: Beryllium Chloride, Silver Oxide
BeCl2, Ag2O
What is an isotope? Explain the differences between Carbon-12, Carbon-13, and Carbon-14.
Carbon-12 is most common: 6 protons, 6 electrons, 6 neutrons
Carbon-13: 6 protons, 6 electrons, 7 neutrons
Carbon-14: 6 protons, 6 electrons, 8 neutrons
Name the following polyatomic ions based on the formula: 𝑁𝐻4+, 𝐶𝑁-, 𝐶𝐻3𝐶𝑂2-, 𝐶2𝑂42-
𝑁𝐻4+ = Ammonium ion
𝐶𝑁- = Cyanide ion
𝐶𝐻3𝐶𝑂2- = Acetate ion
𝐶2𝑂42- = Oxalate ion
550.0 grams of Cl → moles of Cl?
15.51 mol Cl
List the steps to determining the molecular formula when given percent composition and the molar mass of a compound.
1. Divide percentages (in grams) by the molar mass of their respective elements to get the mole values of each element.
2. Divide all mole values by the element with the smallest value (this should give you a whole number).
If it does NOT give you a whole number, the following must be done: a) if number ends in "0.5", multiply all mole values by '2', b) if number ends in "0.3" mulitply all mole values by '3'
3. Once whole number mole values acquired, these will be subscripts to the symbols in the formula.
[This gets you empirical formula]
4. Determine molar mass of the empirical formula
5. Divide the given molar mass by the empirircal molar mass. This yields a whole, unitless number.
6. Multiply subscripts of the empirircal formula by the whole, unitless number determined in the last step.
Write the formula from the name: Iron (II) Sulfide, Magnesium Oxalate
Iron (II) Sulfide = FeS
Magnesium Oxalate = MgC2O4
Organize the following into homogeneous vs heterogeneous mixtures: sand, saltwater, cereal, air
Homogeneous: saltwater, air
Heterogeneous: sand, cereal,
Name the following polyatomic ions based on the formula: CO32-, HCO3-, CrO42-, Cr2O72-
CO32- = Carbonate ion
HCO3- = hydrogen carbonate / bicarbonate ion
CrO42- = chromate ion
Cr2O72- = dichromate ion
8.5∗1032 molecules of Na → grams of Na?
3.2 * 1010 grams Na
A compound has a composition of 52.14% Carbon, 34.73% Oxygen, and 13.13% Hydrogen. In a separate experiment, the molar mass was found to be 138.204 g/mol.
a. What is the empirical formula for this compound?
b. What is the molecular formula for this compound?
a. Empirical Formula: C2H6O
b. Molecular formula: C6H18O3
Identify the bond type and name of the compound: CO2, P2O5.
CO2 = Molecular, Carbon Dioxide
P2O5 = Molecular, Diphosphorus Pentoxide
The element strontium has the following natural abundances. Calculate the average atomic mass.
a) 82.58 % is 88Sr with mass of 87.9056 amu
b) 9.86 % is 86Sr with mass of 85.9093 amu
c) 7.00 % is 87Sr with mass of 86.9089 amu
d) 0.56 % is 84Sr with mass of 83.9134 amu
a) 72.59244 amu
b) 8.47066 amu
c) 6.08362 amu
d) 0.46992 amu
Name the following polyatomic ions based on the formula: ClO-, ClO2-, ClO3-, ClO4-
ClO- = hypochlorite ion
ClO2- = chlorite ion
ClO3- = chlorate ion
ClO4- = perchlorate ion
725 g/mm3 → g/mL?
725000 g/mL
A compound contains 20.0 g Carbon, 3.33 g Hydrogen, and 26.67 g of Oxygen. In a separate experiment, the molar mass was found to be 120.12 g/mol.
a. What is the empirical formula for this compound?
b. What is the molecular formula for this compound?
a. Empirical Formula: CH2O
b. Molecular formula: C4H8O4
Identify the bond type and name of the compound:
Fe2O3, NaNO3
Fe2O3 = Ionic, Iron (III) Oxide
NaNO3 = Ionic, Sodium Nitrate
Organize the following into chemical vs physical mixtures:combustion, evaporation, digestion, boiling
Physical:evaporation, boiling
Chemical: combustion, digestion
Name the following polyatomic ions based on the formula: MnO4-, OH-, SO32-, SO42-, HSO4-
MnO4- = permanganate ion
OH- = hydroxide ion
SO32- = sulfite ion
SO42- = sulfate ion
HSO4- = hydrogen sulfate / bisulfate ion