Physical: Amount of substances Flashcards
What is the definition of Ar
The weighted average of an atom compared to the weight of one carbon-12 atom
Equation for Relative atomic mass of isotopes
Σ Isotope abundance+Isotope mass/100
What is the definition Mr
the ratio of the average mass per molecule of a substance to one-twelfth the mass of an atom of carbon-12.
What is the ideal gas equation and the units
pV = nRT
p=Pascals
V=m^3
n=moles
R=constant 8.31
T=Kelvin
Equation for moles in a liquid
Number of moles (mol) = concentration (mol dm-3) x volume (dm3)
Equation for volume of gas
volume of gas (dm3) = amount of gas (mol) x 24 dm3 mol-1
Determine the number of atoms, molecules and the relative mass of 1 mole of:
Na
H2
NaCl
-The relative atomic mass of Na is 23
Therefore, 1 mol of Na has a mass of 23g mol-1
1 mol of Na will contain 6.02 x 1023 atoms of Na (Avogadro’s constant)
-The relative atomic mass of H is 1.005
2 H atoms in H2, the mass of 1 mol of H2 is (2 x 1.005) 2.01 g mol-1
1 mol of H2 will contain 6.02 x 1023 molecules of H2
Since there are 2 H atoms in H2, 1 mol of H2 will contain 1.204 x 1024 H atoms
-The relative atomic mass of Na and Cl is 22.99 and 35.45 respectively
Therefore, 1 mol of NaCl has a mass of (22.99 + 35.45) 58.44 g mol-1
1 mol of NaCl will contain 6.02 x 1023 formula units of NaCl
Since there are Na and Cl ions in NaCl, 1 mol of NaCl will contain 1.204 x 1024 ions in total
give equations for mass n and mr
n= mass/mr
mass= mr x n
mr= mass/n
what is the relationship between volume and temperature
volume is therefore directly proportional to the temperature (at constant pressure)
explain how to convert for PV=nRT
p=Pascals= if 220KPa change to 220,000 by x 1000
V=m^3= if in dm x by 1000, if in cm x 100,000,0
n=moles
R=constant 8.31
T=Kelvin if in celcius add 273
