C6.1 Flashcards
what is chemical synthesis
raw materials —-> useful products
examples
chemical synthesis
food additives fertilisers dyestuffs paints pigments pharmaceuticals
example of pure acidic compound which is a solid
citric acids
tartaric acids
pure acidic compound
liquid
(3)
sulfuric
nitric
ethanoic
pure acidic compounds
gases
hydrogen chloride
common alkalis
the hydroxides of what?
(3)
sodium
potassium
calcium
PH scale
acids
pH less than 7
pH scale
bases
alkalis pH greater than 7
what are bases?
oxides and hydroxides of metals
pH
acidic neutral alkaline
redish-yellow
green-blue
purple
what are used to detect whether a substance is acidic or alkaline?
indicators:
litmus paper
universal indicator
pH meters
how is the pH of a substance measured?
using a full range indicator
universal indicator solution/ pH meter
hydrochloric acid + potassium hydroxide —>
Potassium chloride + water
sulfuric acid + copper oxide —>
copper sulfate + water
nitric acid + copper oxide —>
copper nitrate + water
what is a neutralisation reaction?
the reaction of acid with an alkali to form a salt
what do acidic compounds produce when dissolved in water?
aqueous hydrogen ions H+(aq)
what do alkaline compounds produce when they dissolve in water?
aqueous hydroxide ions OH-(aq)
acid + base —> neutral salt solution + water
EXAMPLE
hydrochloric acid + potassium hydroxide —> potassium chloride + water
simplest way of writing neutralisation reaction
H+ (aq) + OH- (aq) —> H2O (l)
what are endothermic reactions accompanied by?
a fall in temperature
they take in heat
example of an endothermic change
dissolving ammonium nitrate crystals in water
how can the energy change in an endothermic reaction be shown?
an energy-level diagram
energy is taken in during reaction so products have more energy than reactants
what are exothermic reactions accompanied by?
a temperature rise
give out heat
