Acids And Alkalis Flashcards
What 2 ways can the ph of a solution be measured
Chemical indicator(universal indicator)
Ph probe
What makes an acid an acid
Release hydrogen ions in water
H+
Why is an alklai an alkali
Form hydroxide ions in water
OH-
What will happen when an acid reacts with a base
Neutralisation reaction
Salt+ water
Name the most common acids u will see and their formula
Hydrochloric acid. HCl
Sulfuric acid. H²SO⁴
Nitric acid. HNO³
Name the most common bases and their formula
Sodium hydoxide NaOH
Calcium carbonate CaCO³
What will happen when hydrochloric acid reacts with sodium hydroxide
Neutralisation occurs. Water is produced and a salt ( sodium chloride).
Give the neutralisation reaction in terms of hydrogen ions and hyrdroxide ions
H+ + OH- -> H²O
Why are strong acids strong and weak acids weak
Strong acids ionise fully but weak acids only partially ionise
Which of these are strong acids
Ethanoic acid
Sulfuric acid
Hydrochloric acid
Citric acid
Nitric acid
Sulfuric acid
Hyrochloric acid
Nitric acid
True or false: weak acids are reversible
True
Carbonic acid is desrcibed as a weak acid why is this
Because it does not fully ionise to release hyrdrogen ions
Every time the ph goes down one what happenes to the concentration
Increased by 10x
As the concentration of hyrdrogen ions in a solution increases what happenes to the ph
It decreases
Low ph means higher concentration of hydrogen ions
Whats the difference between a strong acid and a concentrated acid
Concentrated = lots of hyrdrogen ions in that solution
Strong = one that can ionize fully
What products are formed when and acid reacts with a metal oxide
A salt
Water
Acid+metal oxide -> salt+water
What type of reaction is it when an acid and a base react together
Neutralisation reaction
During a neutralisation reaction what reacta with what
Positive hydrogen ions from the acid react with the negative hydroxide ions from the alkali to form molecules of water
What products are formed when an acid reacts with metal hydroxide
A salt
Water
Acid + metal hydroxide -> salt +water
To work out a formula of a salt
Combine the negative ion from the acid and the postive ion from the base
E.g. sodium oxide and hydrochloricacid = sidium chloride
Na²O + HCl -> NaCl
What is the balanced equation for sulphuric acid and sodium oxide
H²SO⁴ + Na²O -> Na²SO⁴ + H²O
What products are formed when hydrochloric acid reacts with potassium hydroxide
Water + potassium chloride
Acid + metal carbonate ->
Salt + water + carbon dioxide
How to obtain soluble salt from an acid-base reaction (experiment)
Part 1 obtain a solution of the soluble salt that we want
- Place dilute acid in a beaker and heat gently
- Add the solid base bit by bit until it stops reacting, in excess
3.isolate the salt solution by filtering out the excess soljd base using filter paper and funnel
Part 2 isolate the soluble salt crystals from the solution
- Heat the solution gently in a water bath until crystals start to form
2.let the solution cool further which will cause more crystals to precipitate
3.filter out the soluble salt crystals using filter paper and funnel
When a soluble salt formed from an acid and an insoluble base how do you know excess is added
Some of the reactant will be left unreacted
Name the polyatomic ions, their formaulas and charges
Sulfate: SO⁴ -2
Nitrate NO³ -
Carbonate CO³ - 2
Hydroxide OH-
Ammonium NH4 +
Table of soluble and insoluble substances
Common salts of sodium potassium and ammonium= soluble
All nitrates= soluble
Common chlorides = soluble (excpet sliver and lead chloride)
Common sulfates= soluble (except lead , barium and calcium sulfate)
Common carbonates and hyroxides = insoluble (excapt sodium potassium and ammonium ones)
Hint: whenever it has potassium sodium and ammonium its soluble and anything that has nitrate at the end is soluble
Balance the equation
Ba(NO³)² + k² CO³ -> BaCO³+ 2KNO³
Ba2+ 2NO³- + 2K+ + CO³-2 -> BaCO3 + 2k+ + NO3-
Ba+2 +CO³-2 -> BaCO³
magnesium carbonate reacts with dilute nitric acid
what products are formed
magnesium nitrate + water + carbon dioxide
barium chloride is an ionic compound and has a high melting point
explain why barium chloride has a high melting point
strong electrostatic forces of attraction
lots of energy to overcome the bonds
when sulfate ions are present insoluble barium sulfate is formed
describe the appearance of barium sulfate
white precipitate
What colour are litmus paper, phenolphthalein and methyl orange in acids and alkalis.
Litmus: red in acids purple, in neutral, blue in alkalin
Methyl orange: red in acids, yellow in neutral, yellow in alkaline
Pheno: colourless in acids or neutrals, pink in alkaline
