Chemical changes

Created by

Sienna Carding

Cards (16)

Write an equation to describe the reaction of a metal with an acid
Metal + acid —> salt + hydrogen
Which element is used to extract a metal from its oxide?
Carbon (but only if the metal is less reactive than carbon)
Give the pH for an a) acid b) neutral c) alkali
a)Acid = <6.9
b)Neutral = 7
c)Alkali = >7.1
Which ions make substances a) Acidic b) Alkali ?
a)Acidic: H+ (Hydrogen ions) b)Alkali: OH- (Hydroxide ions)
Describe how you can determine the pH of a solution
Use an indicator (such as universal indicator) or a pH probe (has a higher resolution and is more accurate as produces numerical value rather than colour scale to interpret)
Name 3 acids used in the science lab
Hydrochloric acid (HCl)
Sulphuric acid (H2SO4)
Nitric acid (HNO3)
Give the reason why some acids are strong and some are weak
Strong acids completely ionise. Weak acids only partially ionise
Name the types of salts produced by each acid
HCl= Chloride salts
H2SO4= Sulphate salts
HNO3= Nitrate salts
How are pH and acid strength related?
As pH decreases by 1 unit, the concentration of hydrogen ions increases by a factor of 10
Describe how a solid salt can be produced from a solution of that salt
Crystallisation- heat the solution to evaporate half the water, leave to cool and crystallise, scrape crystals from the surface and pat dry
Name the electrodes in electrolysis
Anode + and Cathode -
Write an ion equation for neutralisation
H+ + OH- —> H2O
Why do solid ionic substances not conduct electricity?
Fixed ions cannot move to carry electric charge
What is mixed with aluminium oxide in the industrial production of aluminium?
Cryolite
What is the reason for mixing cryolite in with aluminium oxide?
Reduces the melting point therefore saving energy
In the electrolysis of a solution, why might hydrogen be produced at the cathode?
Water is also present, so solution will contain H+ and OH- ions. Hydrogen will be released if it is the least reactive of the metal and H+ ion