Introduction to organic chemistry Flashcards
what over all charge do atoms have ??
Atoms have no overall charge
how would you work out the relative atomic mass ?? (with a percentage)
(%xmass) + (%xmass) + (%xmass) ÷100
how would you work out the relative atomic mass??? (using amount not percentage)
amount = A (Axmass)+(Axmass)+(A×mass)÷(The total of all the As)
What does ToF stand for
Time of flight
What are the four stages of time of flight mass spectrometry
1) ionisation
2) Acceleration of ions
3) separation of charged ions
4) detection
What are the two things might happen during ionisation
Electron impact
OR
Electrospray ionisation
What is electron impact used for
Elements and low Mr compounds
What does high electron impact do
High energy electrons are fired at the sample from a electron gun
This knocks off one electron from each atom/ molecule to form 1+ ion X(g) -) XH+(g)
What is electrospray ionisation used for
High Mr compounds (eg proteins)
What happens in electrospray ionisation
The sample is dissolved in a volatile solvent and injected through a fine hypodermic needle as a fine spray into a vacuum in the ionisation chamber
A very high voltage is applied to the end of the needle where the spray emerges (the needle is positively changed)
The particles gain a protein and becomes positive 1+
What happens during the acceleration of ions
The ions are accelerated using an electric field so that all of the ions have the same kinetic energy
What is the formula for kinetic energy
Kinetic energy = 1/2mv2
What happens during during the separation of charged ions
Ion drift ( ions enter the flight tube)
Ions with different masses have a different time of flight
The lighter ions travel faster and take less time to reach the detector
What is the equation for time of flight
_________
T = d / M
/. —
What is the detector in time of flight mass spectrometry
A negatively charged plate
In time of flight mass spectrometry what is produced when the ions hit the plate
A current (the more ions the bigger the current)
How meny electrons can you have in an ‘S’ shell
2
How meny electrons are in a ‘P’ shell
6
How meny electrons are in a ‘d’ shell
10
Which two elements work differently to the electronic configuration Oder
Chromium and copper
What do the two exception electrons do in their electron configuration
They move electrons to have a full outer shells and the second last shell has a half outer shell
What is ionisation energy
The energy needed to ionise an electron. As you go down the group you need less energy to ionise the electron
What is iso electric
When elements are different but have the same electronic structure (all of these would react the same)
Which energy level will transition metals always lose before their 3D electrons
4s
What is this equation called
Li —) Li+ + e-
An ionisation equation
Why does reactivity increase as you go down a group
Because the electrons are further away from the nucleus because their is less forces of attraction
Why would magnesium (group 3) take more energy to receive compared to the atom before it in a period
Because it has the same number of shells at the element before however has more protons and theirfor will have stronger forces of attraction
What is electron pair repeltion
Where electrons are paired because there is no more space and so repel each other
Why does the sixth element always need less energy to ironise than the element before in a period
Because it experiences electron pair repletion because it’s electrons are having to share a part of a shell therefor the electrons are already repelling each other so it takes less energy to stop this
What is empathy change formation
It is when you make 1 mole of something
What is the equation for atom economy
Designed product
Atom economy = —
If only one product was produced form a reaction what would the atom economy be .
100%
Explain how ions are accelerated detected and have their abundance determined in a time of flight mass spectrometer [3 marks]
The ions are accelerated by an electric field
Where the ions are detected by gaining electrons
And the abundance is determined by the size of the current flowing in the detector
How would you calculate the mass of an element using its abundance e of isotopes
Awnser = (%abundance x mass) and so on plus (%abundance of unknown x ?)
Then you would rearrange the formula
