Topic 5 - Formuale And Eqautions Flashcards
Definition of a mole?
The mole is the amount of substance in grams that has the same number of particles are there are atoms in 12 grams of carbon -12.
Definitions of relative atomic mass?
Relative atomic mass is the average mass of one atom compared to one twelfth of the mass of one atom of carbon-12.
Definition of molar mass (unit)?
Molar mass is the mass in grams of 1 mol of a substance and is given the unit of g/mol.
Explain what is meant by Avogadro constant?
There are 6.02x10^23 atoms in 12 grams of carbon 12. Therefore ‘one mole of any specified entity contains 6.02 x10^23 of that entity’.
Formula for No of particles?
No of particles = amount of substance (in mol) x Avogadro constant.
Definitions of empirical formula
An empirical formula is the simplest ratio of atoms of each element in the compound.
Definition of Molecular formula?
A molecular formula is the actual number of atoms of each element in the compound.
Application of the ideal gas equation?
The ideal gas equation applies to all gases and mixtures of gases. If a mixture of gases is used the value n will be the total moles of all gases in the mixture.
Equations for ideal gas?
pV=nRT
Pressure in Pa
Volume in m^3
Temperature in K
R = 8.314 J/K/mol
How do you calculate empirical formula?
- divide the amount of each element by its molar mass.
- Divide the answers by the smallest value obtained.
- If there is a decimal divide by a suitable number to make it into a whole number
State Avogadro law?
Under the same temperature and pressure, one mole of any gas would occupy the same volume.
How much volume does a gas occupy at room temperature and pressure?
24 dm^3
Why do different gas particles occupy the same volume?
The gas particles are very spread out hence individual differences have no effect.
What are the ideal ways in which gases behave?
a. They are in continuous motion
b. No intermolecular forces experienced
c. Exert pressure when they collide with each other or a boundary
d. No kinetic energy is lost in the collisions
What does concentrations of a solution mean?
It is the amount of solute dissolved in 1 dm^3 of solvent
What are the steps to prepare a standard solution?
- weight the solute using the weigh by difference method.
- In a beaker dissolve the solute using the solvent.
- pour solution into a volumetric flask
- Rinse the beaker using the solution and add it to the flask
- Add solvent to the flask carefully until it reaches the graduation line
- Mix the solutions thoroughly to ensure complete mixing.