chemistry c6 Flashcards
what is an ore
a rock or mineral that contains enough metal to extract from
what are the extraction methods
electrolysis but it is expensive so if metal is less reactive than carbon cheaper methods are used by heating their compounds with C or CO
What are the two stages of copper extraction from copper(II) sulfide?
Roasting in air
Reduction with carbon
What is the word equation for roasting copper(II) sulfide in air?
Copper(II) sulfide + oxygen → copper(II) oxide + sulfur dioxide
What is the word equation for reducing copper(II) oxide with carbon?
copper (II) oxide + oxygen = copper + carbon dioxide
What type of reaction is involved in copper extraction?
redox reaction
What is the role of carbon in the reduction of copper(II) oxide?
Carbon acts as a reducing agent
what is a blast furnace?
a large container used to extract iron from its ore
What are the four raw materials used in a blast furnace?
iron ore (hematite)
coke (carbon made by heating coal)
limestone (purifies iron)
hot air (to maintain high temperatures)
What is the main reducing agent in a blast furnace?
carbon monoxide
What is the first reaction that occurs in a blast furnace?
Coke (carbon) burns in oxygen to form carbon dioxide:
C(s) + O₂(g) → CO₂(g)
How is carbon monoxide produced in a blast furnace?
Carbon dioxide reacts with more coke:
C(s) + CO₂(g) → 2CO(g)
How does calcium oxide help remove impurities?
Calcium oxide reacts with silica (SiO₂) to form slag:
what reactions happen in a blast furnace?
1) coke burns in hot air to make carbon dioxide
2) more coke reduces carbon dioxide to form carbon monoxide
3) carbon monoxide reduces iron (III) oxide to iron at 1500 degrees
what are pollutants?
substances released into the environment that may harm living things
give examples of pollutants
carbon monoxide, oxides of nitrogen, sulphur dioxide, particulates
when is carbon monoxide produced?
during incomplete combustion of fuels containing carbon
what is carbon monoxide?
a toxic, colourless gas that has no taste or smell
what happens when CO is breathed in?
carbon monoxide attaches to haemoglobin in RBCs which reduces the amount of oxygen the blood can carry
what are the effects of carbon monoxide?
drowsiness, difficulty in breathing, death
what are particulates?
small particles produced during incomplete combustion
what happens when particulates are breathed in?
they sit at the bottom of the lungs which causes diseases such as heart disease and bronchitis
how do oxygen and nitrogen react?
they never normally react. only react at very high temperatures in car engines
how is acidic rain formed?
nitrogen dioxide produced from N2 and O2 dissolves in clouds and eventually falls as acid rain
what are the effects of acidic rain?
kill trees and living things in rivers and lakes, erodes stonework, corrodes metals
how is sulphur dioxide formed?
the impurities from burning fossil fuels form sulphur dioxide
what does sulphur dioxide cause
acid rain, breathing difficulties
what is the atmosphere made up of today?
78% nitrogen
21% oxygen
0.9% argon
0.04% carbon dioxide
+ other gases
what was the atmosphere like in the past?
from volcanic activities, huge amounts of carbon dioxide and water vapour were released, but as earth cooled the water vapour condensed to form oceans, leaving CO2 mostly in atmosphere with little/no oxygen
why has the atmosphere changed overtime?
when plants and algae appeared photosynthesis reduced the amount of CO2 in the air, which also released oxygen
