C8: Non-Metals Flashcards
where are the non-metals located in the periodic table?
Elements found principally in groups V-0 of the periodic table.
non-metals have between (1) _______ and (2)______ valence electrons
(1) - 5 (2) - 8
physical properties of non-metals
- most have low melting and boiling points
- poor conductors of heat and electricity
- can be solid liquid or gas at room temperature
- weak and brittle in their solid state
- dull in appearance in their solid state
- low densities
what is an allotrope?
different forms of the same substance
non-metals will either (1)________ or (2)________ their electrons when they react.
- gain
- share
reactions between non-metals and metals are (1)__________ reactions. This is because the non-metals (2) _________ electrons from (3)______ and oxidizing it. the nonmetal itself is (4)________
- redox
- gains
- the metal
- reduced
why is the reaction between metals and non-metals considered redox reactions
electrons are transferred from the metal to non-metal, so the metal is oxidised and the non-metals reduced.
The chemical properties of non-metals are principally reactions between :
- metals
- oxygen
non-metal + oxygen ===>
- acidic oxides eg SO2, SO3, NO2, CO2
- neutral oxides eg, CO, NO, H2O
non-metals + reactive metals ====>
chlorides, oxides, nitrides, sulfides, hydrides
things to consider when preparing a gas
- soluble or insoluble in water
- density compared to air
- reactivity with drying agents
State whether the following non-metals are oxidizing or reducing agents.
- hydrogen
- carbon
- chlorine
- oxygen
- sulfur
- nitrogen
- reducing agent
- reducing agent
- oxidizing
- oxidizing
- reducing
- reducing
How is oxygen prepared?
Decomposition of H2O2 in the presence of manganese oxide catalyst.
- concentrated H2O2 is slowly dropped from a dropping funnel into a sealed flask containing manganese oxide
- as the H2O2 decomposes, oxygen is produced and is collected in a gas jar by downward displacement of water, as oxygen is only slightly soluble in water
- if dry oxygen is required it is then passed over anhydrous calcium chloride in a U-tube and collected by upward displacement of air
how is ammonia prepared?
- warming any alkali usually, calcium hydroxie, with an ammonium salt such as ammonium chloride or ammonium hydroxide
- the ammonia gas produced is passed over calcium oxide in a U-Tube and collected in a gas jar by downward displacement of air.
when preparing ammonia, why is it not passed through water?
it is very soluble and will react with water
when preparing ammonia, why is it passed over calcium oxide?
calcium oxide serves to remove water to obtain anhydrous ammonia
when preparing ammonia, why is glass jar inverted?
ammonia is lighter than air and so is collected by downward displacement of air
what gas/gases can the apparatus below be used to prepare?
- Idenitify the labels
- what is the role of C and E

- Used to prepare ammonia
A - ammonia gas
B - gas jar
C - damp litmus paper for idenitfying ammonia (turns blue)
D - U-tube
E- Calcium Oxide - drying agent to dry ammonia gas
F - reactants (mixture of ammonium salt(usually ammonium chloride) and a base (usually calcium hydroxide)
G - gentle heat
How is carbon dioxide prepared?
- dropping dilute HCl onto marble chips. this reaction produces a salt and carbon dioxide
- Carbon dioxide is passed over calcium chloride or concentrated sulphuric acid in a u-tube to dry it
- Carbon dioxide is then collected by upward displacement of air in a gas jar
why is carbon dioxide collected by upward displacement of air?
it is heavier than air
why can concentrated H2SO4 and anhydrous CaCl2 be used as drying agents for CO2 and O2, but not for ammonia?
Ammonia will react with concentrated H2SO4 and anhydrous CaCl2
when to invert the gas jar or not for collecting gases
- gas is a fluid and so the gas jar will fill from bottom to top.
- gases that are lighter than air will be displaced upward by air so the jar has to be inverted so that the gas can be collected at the ‘bottom’.
- gases that are heavier than air will be displaced downward by air so the jar will be upright so that the gas can be collected at the ‘bottom’.
what is the method of collecting gases that are more dense than air?
collected in a gas jar by upward displacement of air i.e. the gas jar is erect.
what is the method of collecting gases that are less dense than air?
they are collected by downward displacement of air, i.e. gas jar is inverted