Unit 2 Flashcards
Standard solutions and titrations
What is titration used for?
We can use it to find the amount of something. It is quantitative
What does titration involve?
the measurement of a known solution with a known concentration (titrant) is used to find the concentration of the unknown analyte
What happens at the endpoint of a titration?
A colour change. Can use an indicator to make this happen
What is a standard solution?
A solution whose concentration is known accurately
How do you work out moles from conc and volume?
Conc X volume
Moles triangle using conc?
Moles/
Conc X Vol (litres)
Moles triangle
mass #m X mm
What is molarity?
Concentration. It’s the number of moles per litre of solution
How do you find the concentration of a solution?
Moles/ volume in litres
How do you convert cm and ml into dm³ ( dm³ is also litre)
divide by 1000
What is dilution?
Preparing a less concentrated solution from a more concentrated one
If you dilute a substance will you change the number of moles?
No just the concentration
What is an acid
Proton donor
H+ ions
what is a base?
Proton acceptor
OH-
What happens when you add an acid to a base and what are the products?
Neutralisation happens and you will get water and a salt
What is the unit for concentration?
Mol dm⁻³
What is an ionic bond?
the transfer of electrons. The ions are then attracted to each other by electrostatic forces
What is oxidation?
Loss of electrons
What is reduction?
Gain of electrons
What are oxidation numbers used for?
To keep track of electrons in a reaction. Its like the charges.
What is the oxidation state of an atom in an element?
0
What is the oxidation state of oxygen?
-2 (except when its 0₂⁻² this case its -1)
What is the oxidation state of hydrogen?
+1
What is the oxidation state of fluorine?
-1
What is a reducing agent?
something that reduces something. It is oxidised itself
In titrations you need to look at what to work out unknowns?
The ratio of reactants. So if you can work out the number of moles of one reactant and its a 1:1 ratio the unknown reactant will have the same
How do you make half equations
Make two reactions splitting the oxidation and reduction halfs. You can balance them separately
How do you calculate molarity?
Moles of solute/ Litres of solution
Molarity triangle?
Moles of solute
Molarity X Vol (L)
