Stoichiometry
The units of molar mass are
g/mol
For a chemical reaction this represents efficiency
Percentage yield
distance between two successive peaks on adjacent waves
Wavelength
When the pink-colored light of glowing hydrogen gas passes through a prism, it is possible to see how many lines of color?
4 lines of different colors
electrons could have a dual wave-particle nature was theorized by scientist
Louis De Broglie
Ozone, O3, is produced by the reaction represented by the following equation:
NO2 + O2 --> NO + O3
Mr of NO2 = 46.01 Mr of O3 = 48.00
What mass of ozone, O3, will form from the reaction of 2.0 g of NO2?
1. convert mass of NO2 to moles = 2/46.01 = 0.043 moles
2. then find mole ratio
NO2 : O3 mole ratio is 1:1 so moles of NO2 is the same as moles of O3 = 0.043 moles
3. then convert back to mass of O3
0.043 x 48 = 2.09 g
the correct mathematical expression for the relationship among percentage yield, actual yield, and theoretical yield
percentage yield = (actual yield / theoretical yield) * 100
A quantum of electromagnetic energy
Photon
For an electron in an atom to change from the ground state to an excited state, energy must be
absorbed
model of the atom that explains the orbitals of electrons as waves
Quantum Model
The reactant that controls the amount of product formed in a chemical reaction
Limiting Reactant
The Haber process for producing ammonia commercially is represented by the equation
N2(g) + 3H2(g) --> 2NH3(g).
To completely convert 9.0 mol hydrogen (H2) gas to ammonia (NH3) gas, how many moles of nitrogen (N2) gas are required?
1 N2 : 3 H2
x : 9
9/3 = 3 mol
The wave model of light does not explain
the photoelectric effect
If electrons in an atom have the lowest possible energies, the atom is in the
ground state
The quantum number that indicates the orientation of an orbital
magnetic quantum number
For the equation P4(s) + 5O2(g) --> P4O10(s), if 2 mol of phosphorus (P4) reacts with 10 mol of oxygen (O2), the theoretical yield of phosphorus(V) oxide (P4O10) will be
2 mol of P4O10
Use this equation to answer the following question, which represents a reaction used commercially to produce elemental arsenic (As) by heating arsenic(III) oxide (As2O3) with carbon (C).
2As2O3 + 3C --> 3CO2 + 4As
If 6.0 mol of each reactant are available for the above reaction, the mixture remaining after the reaction should contain how many reactants
2As2O3 : 3C
if we have 6 moles of C then it will react with
4 moles As2O3 this will leave behind 2 moles of As2O3
Max Planck proposed that a hot object radiated energy in small, specific amounts called
Quanta
According to the Bohr model of the atom, the single electron of a hydrogen atom circles the nucleus
in orbits
What values can the angular momentum quantum number have when n = 2?
angular momentum quantum is from 0 to (n-1)
so 0, 1
True or False:
In most chemical reactions the amount of product obtained (actual yield) is more than the theoretical yield.
False
In most chemical reactions the amount of product obtained (actual yield) is less than the theoretical yield.
In the formation of silicon carbide represented by the chemical equation SiO2(s) + 3C(s)-> SiC(s) + 2CO(g)
8 mol of each reactant are available for the reaction. What substance is the excess reactant?
1. 1st find ratio of reactants
SiO2 : C is 1:3
2. we have 8 moles each
3. 8 moles of SiO2 requires 24 moles of C to react, but we only have 8 moles of C so the excess reactant is SiO2
another way to explain it is
8 moles of C will react with 2.6 moles of SiO2 so 5.4 moles of SiO2 will remain
The specific wavelengths of light seen through a prism that are made when high-voltage current is passed through a tube of hydrogen gas at low pressure is a
line-emission-spectrum
model of the atom explains why excited hydrogen gas gives off certain colors of light
Bohr's Model of the atom
In the Bohr model of the atom, in which orbit is an electron in its lowest energy state
in the orbit closest to the nucleus