3b- Titrations, Energy and Chemical Tests Flashcards
What pH are acids on the pH scale? Why?
1
Lots of H+ (hydrogen) ions
What pH are alkali on the pH scale? Why?
14
Lots of OH- (hydroxide) ions
What are the neutralisation reactions?
acid + alkali → salt + water
acid + metal oxide → salt + water
acid + metal hydroxide → salt + water
What is the reaction when testing for carbonates?
acid + carbonate → salt + water + carbon dioxide (fizzing)
What is the reaction for reactive metals?
acid + metal → salt + hydrogen
What is titration?
A way to measure volumes precisely
What does titration find out?
Finds out an unknown concentration by using a known concentration
What are the steps of titration?
- pipette measures an accurate volume of the solution and emptied in a conical flask
- indicator added to flask
- another chemical added into burette (with known concentration)
- solution from burette gradually added with swirling to mix indicator
- colour change shows the end point
- volume of solution added from burette is noted and used to calculate concentration
What is reduction?
Gaining electrons
What is oxidisation?
Losing electrons
Electrolysis of Brine-
What gas is produced at the positive electrode?
Chlorine gas
Electrolysis of Brine-
What gas is produced at the negative electrode?
Hydrogen gas
Electrolysis of Brine-
What solution is formed?
Sodium hydroxide
Electrolysis of Brine-
What is attracted to the cathode?
Hydrogen (H+) is attracted to the cathode (not sodium)
Greater force of attraction- not as many shells shielding the nucleus
What is the test for oxygen?
Relight a glowing splint
What is the test for hydrogen?
It makes a popping noise when lit
What is the mnemonic for anode and cathode?
PANIC
Positive Anode Negative Is Cathode
What is the relative atomic mass equation?
(mass of element needed ÷ total mass of elements) x weight or tonnes needed
What is the formula for moles, mass, and atomic or formula mass?
mass = moles x atomic or formula mass
What colour do the flames turn with these metal ions? Lithium Sodium Potassium Calcium Barium
Lithium- crimson Sodium- yellow Potassium- lilac Calcium- red Barium- green
What is the volume measured in and what is the conversion?
dm3
cm2 ÷ 1000 = dm3
What is the formula for moles, volume and concentration
moles = volume (dm3) x concentration (mol.dm-3)
What are the steps for titration calculations?
1) Work out chemical equation (acid + alkali → salt + water) and balance
2) Find ratio
3) Write table for concentration and volume of the chemicals
4) Use known chemical for vol x conc to find out moles
5) Put moles into ratio for the other chemical (if needed)
6) Use moles ÷ vol = concentration
