Amount of Substance Flashcards
Define relative atomic mass.
The average mass of one atom compared to one twelfth of the mass of one atom of carbon-12.
Define relative molecular mass.
The average mass of a molecule compared to one twelfth of the mass of one atom of carbon-12.
What is Avogadro’s number?
6.022 x 10^23
Equation linking moles mass and Mr?
Moles = Mass/Mr
In Moles = Mass/Mr, what is mass measured in?
Grams
In Moles = Mass/Mr, what is moles measured in?
Mol
Ideal gas equation?
PV = nRT
In the Ideal Gas Equation what are the units for the following:
P
V
n
T
Pascals - Pa
Volume - m^3
Moles - mol
Kelvin - K
What is R in the ideal gas equation?
8.31
How to convert from degrees celsius to kelvin?
Add 273
Equation linking n c v
N = CV
In the equation n=cv, what are the following measured in:
n
c
v
n - Moles - Mol
c - Concentration - moldm^-3
v - Volume - dm^3
Cm^3 to Dm^3?
Divide by 1000
Dm^3 to M^3?
Divide by 1000
1000mg in g?
1g
1 tonne in kg?
1000kg
Equation that includes the avogadro’s constant?
Number of particles = moles x avogadro’s constant
Density equation?
D = m/v
Density is measured in?
gcm^-3
In the d=m/v, what is volume measured in?
cm^3
Define empirical formula.
The simplest whole number ratio of atoms of each element in the compound.
Define molecular formula.
The actual number of atoms of each element in the compound.
What are some potential errors when using a gas syringe?
Gas can escape before the bung is inserted.
Percentage yield equation?
Actual yield/Theoretical yield x 100
Percentage atom economy equation?
Mass of useful products/Mass of all reactants x 100
Why do chemists want a high percentage yield?
It means there has been an efficient conversion of reactants to products.
Why do chemists want a high atom economy?
So that the maximum mass of reactants ends up in the desired product .
