Module 2 Flashcards
(38 cards)
Relative Isotopic Mass?
The mass of an isotope of an atoms of an element relative to 1/12 of carbon-12.
Relative Atomic Mass
The weighted mean mass of an atom of an element relative to 1/12 of the mass of the carbon-12 atom.
How to use a mass spectrometer?
-Place sample in the mass spec
-Sample is vapouriest and then ionised to form positive ions.
-The ions are accelerated. The heavier ions move more slowly and are more difficult to deflect that lighter ions so the ions of each isotope are separated.
-the ions are then detected on the mass spec as a mass-to-charge ratio m/z. The greater the abundance, the greater the signal.
What does the Avogadro Constant represent
Number of atoms/particles
Relative Formula Mass
Compares the mass of a formula unit with the mass of an atom of carbon-12.
What is water of crystallisation?
When crystals have a crystalline structure where they are hydrated.
What are the assumptions made when you find the formula of a hydrated salt?
- All of the water has been lost
- There was no further decomposition
Equation that involves concentration and moles
n = c x V
What are the conditions of RTP
20c/ 293 k
101 kPa
What is molar gas volume?
Volume per mole of gas molecules at stated temp and pressure.
24dm3mol-1
What is the ideal gas equation?
pV = nRT
What does ‘R’ stand for in the ideal gas equation?
Ideal Gas constant = 8.31 Jmol-1K-1
What is a limiting reagent?
The reactant that is not in excess will be completely used up first and stop the reaction.
How is a salt formed?
By a base replacing a H+
Atomic Orbitals
A region around the nucleus that can hold up two electrons in opposite spins.
How is a covalent bond different to an ionic?
The attraction is localised as it acting solely between the share pair of electrons.
Average Bond Enthalpy
A measurement of covalent bond strength.
What does a solid line represent in shapes of molecules?
A bond in the plane of the paper
A solid wedge?
Bond comes out of the plane of the paper
Dotted wedges?
bonds go into the plane of the paper
Angle - 109.5. BPs - 4
Tetrahedral
Angle - 107 BPs - 3. LPs- 1
Pyramidal
Non-linear
2 lone pairs
2 bonds pairs
104.5.
[there 4 pairs overall but two are lone pairs so 109.5 - 2(2.5) as for every lone pair you subtract 2.5 from the angles]
Linear
Angle - 180
2 Bond pairs