A1 Flashcards
define acid
substances that dissociates in water to form h+ ions
give an example of an acid
HCL—> H+ + CL-
define base
substances that react with acids to form water and salt
define alkali
a base that dissolves in water to form OH- ions
define amphoteric
substances that can act as both acid and base
what is the chemical equation for aluminium oxide?
AL2O3
is alumina chemically inert?
yes it is, however under some conditions it is not, for example it can react with hot bases and acids
is alumina amphoteric? and why
yes because it can react with hot bases and acids only
what are some of the uses of alumina?
since it is chemically inert, can be used for filler, paint, sunscreen and glass
it is also an effective desiccant.
what ion does an element become if it loses an electron?
postive ion
what ion does an element become if it gains an electron?
negative ion
what is the equation of alumina acting as a base?
AL2O3+6HCL—> 2ALCL3+3H20
what is the equation for alumina acting as a acid?
AL2O3+6NaOH+3H2O—>2Na2AL(OH)6
how are salts formed?
salts are formed when h+ ions in acids are replaced with another positive ion. this is usually with either a metal ion or ammonium.
what is the chemical formula of ammonium?
NH4+
what are metal oxides?
metal oxides are bases. bases react with acids to form salt and water.
what is the equation of metal oxides?
metal oxides+ acid–> salt+ water
give an example of metal oxide.
CaO+2HCI–> CaCl2+H20
what are metal hydroxides?
they’re alkalis. alkali is a base dissolving in water to form OH- ions.
what is the equation of metal hydroxides?
metal hydroxides+ acid–> salt + water
what do metals form?
positive ions
what do non metals form?
negative ions or none sometimes
why are metals more reactive down the periodic table?
because the outermost shell is far from the nucleus.
what bonding do metals have?
they have metallic bonding
what are some properties of metals?
they’re:
- malleable
-great conductors of heat
-high mp&bp
-shiny
-sonorous( make sound)
properties of non metals
-poor conductivity
-low mp&bp
-brittle
-low density
-dull
most of them are gaseous
what is meant by effluent?
liquid waste that is discharged into a river or stream
what happens when factories use sulfuric acid?
it can make the effluent acidic, which can lower the pH of the water, damaging the environment.
what can you do to increase the pH?
bases can react with acids such as calcium hydroxide, which will form salt and water, neutralising the pH of the water.
what is the chemical equation of calcium hydroxide?
Ca(OH)2+H2S04–> CaSo4+2H20
what is meant by refractory material?
Refractory material is material that is physically and chemically stable at very high temperatures
how is alumina a refractory material? and what is it used for?
it maintains its strengths at high temps and its chemically and physically stable.
its an excellent material to be used inside furnaces and reactors.
why are transition metals and compounds useful catalysts within industries?
allow reactions to take place at lower temperatures:
which reduces the amount of energy needed in industries and reduces costs of production.
they also provide alternative reaction pathways with lower activational energy.
what are catalysts?
substances that increase rate of reaction
what is activation energy?
the minimum amount of energy needed between colliding particles to have a successful collision to take place.
