UNIT 1- acids and bases Flashcards
what is the pH scale?
it is a continuous range from below 0 to above 14
what is the pH of an acid?
LESS than 7
what is the pH of an alkali?
MORE than 7
what is the pH of pure water and neutral solution?
7
how do you measure pH?
-compare the colour of the solution to a colour chart
-use electronic pH probes to accurately measure the pH
what are acids?
they are compounds which produce H+(aq) ions when dissolved in water
what are alkalis?
they are compounds which produce OH-(aq) ions when dissolved in water
what is the formula and ions present for hydrochloric acid?
formula=HCl
ions present= H+(aq) & Cl-(aq)
what is the formula and ions present for sulfuric acid?
formula=H2SO4
ions present= 2H+(aq) & SO4(2-)(aq)
what is the formula and ions present for nitric acid?
formula=HNO3
ions present= H+(aq) & NO3-(aq)
what is the formula and ions present for sodium hydroxide?
formula=NaOH
ions present=Na+(aq) & OH-(aq)
what is the formula and ions present for pottasium hydroxide?
formula=KOH
ions present=K+(aq) & OH-(aq)
what is the formula and ions present for calcium hydroxide?
formula=Ca(OH)2
ions present=Ca2+(aq) & 2OH-(aq)
what do concentrated acids and alkalines contain?
a large amount of acid or alkali in a small volume of water
what do dilute acids and alkalines contain?
a small amount of acid or alkali in a large volume of water
what is equal in neutral solutions?
the concentration of H+(aq) ions and OH-(aq) ions
what is a reversable reaction?
it is a reaction which can proceed in both directions
what is equilibrium?
it is when the rate of the forward and reverse reactions are equal
what happens at equilibrium?
the concentrations of reactants and products remain constant, although not necessarily equal
what is the equation for equilibrium?
forward reaction(rp) = backward reaction(rb)
what happens during equilibrium in water?
water molecules are constantly breaking up to form ions which in turn are constantly combining to reform water molecules
what does equilibrium in water exist in?
it exists in pure water and all aqeous solutions
what is the equation for equilibrium in water?
H2O <_-> H+(aq) + OH-(aq)</_->
how many water molecules break up into ions? and what does this make water?
only 1 in every 55 million, therefore water is a poor conductor of electricity
what is pH?
it is a measure of the hydrogen ion concentration
what do acidic solutions contain?
more H+(aq) ions than pure water
what do alkaline solutions contain?
more OH-(aq) ions than pure water
what do neutral solutions contain?
they contain an equal amount of OH-(aq) ions and H+(aq) ions
what happens if you add water to an acid?
the pH of the solution increases as the concentration of H+(aq) ions decreases
what happens if you add water to an alkali?
the pH of the solution decreases as the concentration of OH-(aq) ions decrease
what are all metal oxides?
all metal oxides are bases however not all bases are metal oxides
what can non-metals burn in oxygen to produce?
they can burn in oxygen to produce non-metal oxides
what happens when non-metal oxides dissolve in water?
they form acidic solutions
what is formed if the metal oxide is soluble in water?
an alkali
what do all soluble metal hydroxides dissolve in water to produce?
alkaline solutions
what doesnt affect the pH of water?
insoluble oxides and hydroxides
what is ammonia the common name for?
nitrogen hydride
what is ammonia?
-it is a gas that will neutralise acids therefore it is a base
-it is a covalent molecule which dissolves in water to produce an alkaline solution
what happens during a neutralisation experiment?
-acids react with bases
-the pH of the solution moves towards 7
what are the bases?
-metal oxides
-metal hydroxides
-metal carbonates
-ammonia
what are the four main reactions of bases?
-acid + metal oxides = salt + water
-acid + metal hydroxides = salt + water
-acid + metal carbonate = salt + CO2 + water
-acid + metal = salt + hydrogen
what are some common acids?
-vinegar,
-lemonade,
-soda water,
-coke,
what are some common alkalis?
-baking soda,
-dishwashing powder,
-bleach,
What acid causes acid rain?
Sulfur dioxide
What is the test for oxygen?
Light a splint, then put it out, put the glowing splint up to the end of an open test tube, if the splint is relit then oxygen is present
What is the test for carbon dioxide?
When carbon dioxide is shaken with or bubbled through limewater the limewater turns cloudy
