[FINAL] All formulas and when to use Flashcards
Density
Q: What is the mass of a 10.00 mL sample of water at 25 degrees Celsius? The density of water at 25 degrees is 0.99707 g/cm^3.
Mass/Volume
A: 99.71 (pg 9)
Kelvin to Celius
Q: At Mt. Everest water boils at about 70 degrees Celsius. What is the temperature in Kelvin?
Kelvin= celsius +273
A: 343 K (pg 11)
Celsius to Fahrenheit
Q: What is the temperature of a human body, 36.6 degrees C in degrees F?
C= 5/9(F-3)
F=9/5(C) +32
A: 97.9 F (pg12)
Mass number
Q: How many neutrons are in Nickel 59?
Mass Number, A= # of protons + # of neutrons
A: 31
Atomic number
Atomic #, Z= number of protons which = number of electrons
Average atomic mass
Q: What is the avg. atomic mass of carbon?
M1= 12, f1=.9889, M2= 13.003355, F2= .0111
Average Atomic mass= (fractional abundance (f)1 * isotpic mass (M)1) + (fractional abundance (f)2 * isotpic mass (M)2)
A: 12.011 (pg 26)
Avogadro’s number
Q: How many atoms of Ar are contained in .345 mole of Ar?
Avogadro’s number= 6.022 *10^23 which equal 1 mole of an atom or molecule
A: 2.08 *10^23 atoms (pg 42)
mols
Q: how many mols of NH3 ( Mm= 17.03 g/mol) are there in 84.12 g of NH3?
mols= mass/ molar mass
A: 4.939 mol NH3 (pg 44)
Mass percent of element X in a compound
Q: calculate the mass percent of H in H2O
Mass percent of element X in a compound= (mass of element X/ mass of 1 mol of the compound)
A: 11.189% (pg 45)
Sample Question: How many grams of carbon dioxide (CO2, Mm= 44.010 g/mol) can be prepared from the complete combustion of 3.25 g of acetylene (C2H2, Mm = 26.038 g/mol)
2C2H2 (g) > 4CO2 (g) + 2H2O (g)
A: 11g
pg 52-53
Percent Yield
Q: A reaction theoretically can produce 7.65 g of a product, however, only 5.67 g have been obtained in the laboratory. What is the percent yield of the product in this reaction
Percent Yield= (actual yield/ theoretical yield) * 100%
A: 74.1 % (pg 62)
Sample Question: write the net ionic equation for Ca(NO3)2 (aq) + Na2CO3 (aq) > CaCO3 (s) + 2NaNO3 (aq)
A: Ca^2+ (aq) + CO3^2- (aq) > CaCO3 (s)
pg 72 and review page soluble ionic compounds on pg 67
Molarity
Q1: What is the molar concentration of .5 L solution containing 4.5 moles of C6H12O6?
Q2: How many grams of NaCl are there in 1.00 L of the solution which is .100 M?
Molarity= moles of solute (mol) / Volume of solution (L)
symbols for Molarity: C, [solute], M
A1: 9.00 M (pg 79)
A2: 5.84 g (pg 80)
mols in terms of molarity
Q: What mass of NaOH is needed to precipitate Cd^2+ ions from 20.0 mL of .100 M of Cd(NO3)2 solution?
Cd(NO3)2 + 2NaOH > Cd(OH)2 + 2NaNO3
mols = Molarity * Volume
A: .160 g NaOH (pg 85-86)
Sample Question: How many moles of methane were combusted at a constant pressure if 180 kJ of heat were released?
CH4 + 2O2 > CO2 + 2H2O; delta H = -890 kJ
A: .2 mol CH4 (pg 93)