Acids And Alkalis Flashcards
What do acids release in aqueous solution?
H+ ions
What do alkalis release in aqueous solution?
OH- ions
What is an alkali?
A water soluble base
What is the formula for hydrochloric acid?
HCl
What is the formula for sulfuric acid?
H2SO4
What is the formula for nitric acid?
HNO3
What is the formula for Ethanoic acid?
CH3COOH
What are the 3 most common bases?
1) NaOH
2) KOH
3)NH3
What is the difference between a strong acid and a weak acid?
A strong acid fully dissociates in aqueous solution whereas a weak acid only partially dissociates in aqueous solution.
What is a neutralisation reaction?
The reaction of an acid with a base
What is the ionic equation for a neutralisation reaction?
H+ (aq) + OH- (aq) —> H2O (l)
What is the reaction of an acid and carbonate?
Acid + carbonate —> salt + water + CO2
What is the reaction between an acid and metal oxide?
Acid + metal oxide —> salt + water
What is a titration?
A practical method where a standard solution of known concentration is reacted with a solution of unknown concentration in order to determine the concentration of this solution
What is the method for preparing a standard solution?
1) weigh sample solid
2) transfer solid to beaker
3) add distilled water and stir with glass rod until dissolved
4) transfer to a volumetric flask with washing’s of equipment used
5) make up to 250cm3 mark with distilled water
6) shake the flask
What systematic errors occur in preparing the standard solution?
Errors on the balance
Lost substance in transfer
Overfilling the volumetric flask
What is the 1st step of a titration?
Fill the curette with the standard solution of known concentration, ensuring the jet space in the burette is filled and doesn’t contain air bubbles
What is the 2nd step of a titration?
Use the pipette filler to transfer 25cm3 of the solution with unknown concentration into a conical flask
What is the 3rd step of a titration?
Add 2 or 3 drops of indicator to the conical flask
What is the 4th step of a titration?
Record the initial burette reading
What is the 5th step of a titration?
Titrate by adding the acid from the burette until the indicator undergoes a definite, permanent colour change
What is the 6th step of a titration?
Record the final burette reading and calculate the titre volume
what is the last step of a titration?
Repeat until at least two concordant results are obtained (within 0.1cm4 of each other)
What is the equation for % uncertainty?
No. Times measured x absolute uncertainty/ value measured
How can you reduce the % uncertainty of a titre?
Increase titre volume needed - increasing concentration/volume of conical flask substance or decreasing concentration of burette substance
