C8 Acids And Alkalis Flashcards
State the pH of a strong acid, strong alkali and neutral solution
1,14,7
State three different indicators.
Litmus paper, universal indicator, methyl orange, phenolphthalein.
Identify the indicator which turns pink in shampoo.
Shampoo is alkaline, phenolphthalein
State the polyatomic ion formed when sulphuric acid dissociates.
SO4 2-
The ____________ the pH the higher the concentration of hydrogen ions in solution.
Lower
If the concentration of hydrogen ions increases by 1000 fold and the end result was pH 2, what pH did the first solution have?
1000 fold increase = 3 steps on the pH scale… pH5
True or false there are no ions present in pH7 pure water.
False thee are equal numbers of hydroxide and hydrogen ions at low concentrations
Strong acids…
Fully dissociate
Weak acids…
Partially dissociate
Name 3 strong acids
Hydrochloric, metric, sulphuric
Name 3 weak acids
Boric, carbonic, ethanoic.
Tin oxide is a base, describe how you would make tin chloride in a neutralisation reaction.
Mix excess tin oxide with hydrochloric acid, filter off excess. Rinse filter paper with distilled water, heat tin chloride solution in evaporating dish.
Why is it critical to use excess copper oxide when making copper sulphate crystals in a neutralisation reaction?
So that all of the acid is neutralised.
Nitrate ion
NO3 -1
Charge of a sulphate ion
SO4 2-
Charge of a carbonate ion
CO3 2-
Formula for sodium sulphate
Na2SO4
___________________ acid is found in the stomach because…
Hydrochloric acid… Help digest food, kill bacteria.
Titration are used when…
Making soluble salts and a know endpoint is needed.
Why is universal indicator a poor choice for titrations?
It doesn’t have a sharp end point like methyl orang of phenolphthalein
Acid and limestone —>
Make salt, water and carbon dioxide
Ionic equation for dissociation of ethanoic acid.
CH3COOH –> CH3COO- + H+
Ionic equation for magnesium carbonate and hydrochloric acid…
2H+ + CO32- —> H2O + CO2
Extra brownie points for state symbols.
Magnesium and chloride ions are spectators.
Common Sodium, potassium and ammonium salts tend to be…
Soluble
All __________ are soluble
Nitrates
Potassium chloride, silver chloride, lead chloride… Odd one out
Potassium chloride is soluble
Name two suitable reagents to make barium sulphate in a precipitate reaction.
Barium nitrate, potassium/sodium/ammonium sulphate is the obvious choice :-)
Turns limewater from colourless to cloudy…
Carbon dioxide.
Charge on a hydroxide ion
-1
Pipettes are used in titrations instead of measuring cylinders because…
They provide a more accurate and repeatable means of measuring out a know volume of liquid.
Dodgy titration, how do you ensure your result is reliable?
Repeat your experiment.
A student has 100ml of sodium hydroxide solution, it is neutralised in a titration by 25ml of an acid stock. What does this tell you about the acid?
The concentration of the acid is 4 times greater in magnitude.
What did the police officer say to the acid who hit an alkali?
That’s assault!
It’s all about the base, bout the base…
No acid.
If your not part of the solution…
Your part of the precipitate.
What’s effervescence? When might you see it in this topic?
Bubbles! Bubbles! CASHOCO reactions, MASH reactions.
25g of sulphuric acid is dissolved into 200cm3 of water, what’s the concentration?
0.125g/cm3
Write the formula and state symbol for a saline solution.
NaCl (aq)
Describe a concentrated acid
Large number of hydrogen ions in a proportionally small volume.
Describe a strong acid
An acid which is a strong proton donor and reliably dissociates with high percentage of success.
