Chemical Quantities. Ways to measure matter: Count how many of something you have Weigh it (or...
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Transcript of Chemical Quantities. Ways to measure matter: Count how many of something you have Weigh it (or...
Ways to measure matter: Count how many of something you
have Weigh it (or mass it) Volume
Units that refer to a specific # pair = 2 dozen = 12
1 mole = 6.02 x 1023 atoms, molecules, ions, formula unitsA.k.a. Avogadro’s Number
1 mole of a substance contains 6.02 x 1023 representative particles
Representative particle: refers to the species present in a substance: atoms, molecules, ions
SubstanceSubstance Rep. ParticleRep. Particle FormulaFormula R.P. in 1 molR.P. in 1 mol
Atomic NAtomic N AtomAtom NN 6.02 * 106.02 * 102323
Nitrogen GasNitrogen Gas MoleculeMolecule NN22 6.02 * 106.02 * 102323
WaterWater MoleculeMolecule HH22OO 6.02 * 106.02 * 102323
Calcium ionCalcium ion IonIon CaCa+2+2 6.02 * 106.02 * 102323
Calcium Calcium flourideflouride
Formula unitFormula unit CaFCaF22 6.02 * 106.02 * 102323
SucroseSucrose MoleculeMolecule CC1212HH2222OO1111 6.02 * 106.02 * 102323
How big is one mole?One mole of sand would cover L.A.
to a depth of 600 meters (1,968 ft)
Marbles would cover the earth to a depth of 40 miles
Atomic mass unit of all elements are based off the Carbon – 12 atom
The atomic mass of an element expressed in grams is the mass of a mole of the element
How many atoms are in one mole of magnesium?
To calculate the molar mass of a compound, find the number of grams of each element in one mole of the compound. Then add the masses of the elements in the compound
What is the molar mass of CO2
Avogadro’s Hypothesis – equal volumes of gases at the same temperature and pressure contain equal numbers of particles
Standard temperature and pressure – (STP)
Standard temp: 0oC pressure: 101.3 kPa or 1 atm
@ STP 1 mole of gas occupies 22.4 L
22.4 L = molar volume of a gas @ STP
Molar mass = density @ STP x molar volume @ STP
The density of a gas containing Carbon and Oxygen is found to be 1.946 g/L @ STP. What is the molar mass of the compound?
The relative amounts of the elements in a compound are expressed as percent composition
The percent by mass of an element in a compound - the number of grams of the element divided
by the mass in grams of the compound...multiplied by 100%.
Empirical formula: gives the lowest whole number ratio of the atoms of the elements in a compound
What is the empirical formula of a compound that is 67.6% mercury, 10.8% sulfur and 21.6% oxygen?