2.1.3 Amount Of Substance Flashcards
How do you find moles from a mass
moles= mass/mr
hoe do you find moles from volume and concentration
moles=volumeXconcentration n=vc
how do you find moles from a gas
moles (gas) = vol (dm3)/ 24 OR vol (cm3)/ 24000
what is avogadro’s Law?
under the same temperature or pressure, any mole of a gas will occupy the same volume
how much volumr does one mole of a gas occupy at standard temp/pressure
24 dm3 or 24,000 cm3
what is the ideal gas equation?
pV=nRT
p= pressure (Pa) V= volume (M^3) n= moles R= gas constant (8.314) T= temperature (k)
How many Pascal is 1atm
1atm = 101,000 PA
how do you turn Celsius into Kelvin?
Add 273
what is a standard solution?
a solution of known concentration
how do you prepare a standard solution?
1) weight the solute using the weigh by difference method
2) in a beaker, completely dissolve the solute in the solvent
3) pour the solution into a volumetric flask
4) rinse the beaker with distilled water to get any residual solution into the flask
5) Add distilled water (solvent) until the graduation line
6) mix thoroughly to ensure its mixed
give reasons why you may not have a 100% percentage yield
- The reaction is at equilibrium
- impure reactants
- other side reactions may be happening
- reactants/products left behind in transferral
- loss of products doing purification/separation
- kara is awesome :D NO SHES NOT
how is percentage yield calculated
percentage yield = actual yeild (mol)/theoretical yeild X 100
what does atom economy mean?
the amount of desired product compared to all products formed
how do you calculate atom economy
atom economy = (Mr/sum of mr of all products) X100
does 100% yield mean 100% atom economy?
No because there may be multiple products in the yield so there may not be 100% o the desired product
state what is meant by the term empirical formula
The simplest whole number ratio of atoms (of each element) present in a compound
what is a subshell?
The independent energy levels housing electrons in a shell of electrons
e.g. 3s2 3p6 3d10 are all subshells
what are orbitals?
pairs of electrons in a shell
what is meant by the term isotope
an atom of an element with the same number of protons but a different number of neutrons
why do some different isotopes of the same element have the same chemical properties?
Because they have the same electron configuration
what is meant by the term relative atomic mass? (Ar)
The weighted mean mass of an atom compared with 1/12 of the mass of a single carbon 12 atom
what is meant by the term relative isotopic mass?
the mass of an isotope relative to 1/12 th of the mass of an atom of carbon 12
how do you calculate relative atomic mass (Ar) from % abundances?
Ar = (mass x Abundance) + (mass x Abundance) / total abundance
you can use this to find out the Ar of an isotope simply by rearranging
What is meant by the term relative formula Mass? (Mr)
The Mr of a compound is the sum of all the atomic masses of each atom in the formula
what is the equation for finding the abundances of isotopes?
https://docs.google.com/document/d/17_ChjSZF0Sc_dkYUKqLJrHYHaeOCpJga1vV2fxhPb5M/edit?usp=sharing
%abundance = (pull / difference) x100
what is Avogadro’s number?
6.02x10^23
what is the value for the specific heat capacity of water?
4.18
what is the value for the gas constant?
8.31
