Amount Of Substance Flashcards
What is the symbol for amount of substance?
n
What does the Avogadro constant represent?
The number of atoms per mole of the carbon-12 isotope.
State Avogadro’s law.
Under the same temperature and pressure one mole of any gas would occupy the same volume.
Why do different gas particles occupy the same volume?
The gas particles are very spread out, hence individual differences has no effect.
How to calculate moles when gas volume is given?
Moles = volume (dm3) / 24 (dm3)
What are the ideal ways in which gases behave. (5)
- they are in continuous motion
- non intermolecular forces experienced
- exert pressure when they collide with each other or container
- no kinetic energy is lost in the collisions
- when temperature increases, kinetic energy of gases also increase
Write down the ideal gas equation.
pV = nRT
1 atmospheric pressure is equal to how many pascal?
1 atm = 101325 Pa
0 degrees is equal to how many kelvin?
273 K
What does concentration of solution mean?
The amount of solute dissolved in 1 dm3 of solvent.
How do you calculate moles when concentration and volume are given?
Moles = conc x volume
What is a standard solution?
A solution of known concentration
Write down the steps to prepare a standard solution.
- Weigh the solute using the weigh by difference method
- In a beaker dissolve the solute using the solvent
- Pour the solution into a volumetric flask
- Rinse the beaker using the solution and add it to the flask
- Add solvent to the flask carefully ipuntil it reaches the graduation line
- Mix the solution thoroughly to ensure complete mixing
What is a species in a chemical reaction?
Any particle that takes part in a reaction.
What are the reasons for not obtaining 100% yield?
- reaction may be at equilibrium
- the reactants may be impure
- side reactions could happen
- reactants or products may be left behind while transferring
- loss of products during separation and purification
