Amounts of Substance Flashcards
The Mole, The Formulae, The Quantities. Its all here
1
Q
How much in a mole
A
6.02 times 10^28
2
Q
A
3
Q
What is molecular masss?
A
This is the mass in grams in each mole of a substance
4
Q
What is the difference of relative MOLECULAR and ATOMIC mass?
A
- Made up od distinct, COVALENTLY BONDED molecules H2, I2 C6H12O6
- Within a giant interconnected IONIC LATTIC molecules e.g. NaCl
5
Q
How to find Empirical Formula?
A
- Find the moles per atom
- Find the smallest integer ratio
- number of atoms = ratio number
6
Q
How to find Molecular Formula?
A
- Find the Mr of this bigger molecule
- Using empirical formula, divide the “Mr” with both
- Use this comparison value to multiply to emipirical formula!!
7
Q
What is the Water of Crystallisation?
A
- This is when the water is NOT chemically fixed within the cryctalline structure, but only the overall part
e.g. (CuSO4.6H2O)
8
Q
Define Anhydrous, and what happens in this state
A
- This is when water is removed from the overall crystal struture.
- May become a white and crumbly powder as a result
9
Q
How to ensure accuracy when dealing with Water of Crystalisation?
A
- Heat compound to a constant mass until no further decomposition
- Repeat the experiment and calculate and average…..
10
Q
What ASSUMPTIONS must be made during Ideal Gas Equations?
and GIVE THE EQUATION
A
- No intermolecular forces in gas
- Ellastic collisions occuring
- **Negligable sizes **of molecules
- Complete random motion of particles
pV=nRT !!!!!!!!!!!!!!
11
Q
What is Stoichometry?
A
- This is the act of using RATIOS in EQUATIONS for find MOLES in calculations
12
Q
What is the best way to do moles/limiting/concentration calculations
A
- Practising, practising and practising with EXAM QUESTIONS
13
Q
Eqaution for Atom Economy!
A
Sum of desired products / sum of all products * 100
14
Q
Equation for Percentage Yield!
A
Actual / Theoretical * 100
15
Q
Finding the Limiting Reagent?
A
- Find the amount of moles that comes as a lack, preventing the reaction to proceed further
