Chemistry- Some non-metals and their compounds

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How can hydrogen be displace?
With a more reactive metal
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What are the properties of hydrogen?
Lightest of all gases, colourless, combines with oxygen to form water which gives out a lot of energy, reduces less reactive metals
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How do we take in nitrogen?
By eating proteins
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What are the properties of nitrogen?
Colourless, odourless, slightly soluble, unreactive, reacts with hydrogen to form ammonia, combines with oxygen to form acidic oxides
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Why is ammonia the world's second most manufactured chemical?
It is used in fertilisers
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How can ammonia be made?
By reacting with a base... 2NH4CL+Ca(OH)2 +2H2O+ 2NH3
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What is the formula for ammonia?
NH3
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What are the properties of ammonia?
Colourless, denser than air, solution is alkaline (pH9), very soluble in water, strong chocking smell, solution reacts with acid to form salt
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How to chemically test for ammonia?
It reacts with hydrochloric gas to form white smoke
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Why is it difficult to manufacture ammonia?
Reaction is reversible
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By what process is ammonia manufactured?
The Haber process
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What are the reactants for the Haber process?
Nitrogen and hydrogen
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How is nitrogen obtained for the Haber process?
Nitrogen is obtained from air. Oxygen is removed by burning hydrogen. 2H2+O2= 2H2O. Heat given out in the reaction is used in the plant.
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How is hydrogen obtained for the Haber process?
Usually made by reacting natural gas (methane) with steam CH4+2H2O=CO2+4H2. It is also made by cracking hydrocarbons from petroleum C2H6=C2H4+H2
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Describe steps in Haber process.
Two gases (hydrogen and nitrogen) are mixed and scrubbed to remove impurities. Gas mixture is compressed=> pressure reaches 200 atmospheres. Gas flows into (catalyst)converter w/ iron beds at 450C. 15% is ammonia. Mixture cooled=> liquid.
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Why is the ammonia reaction never complete?
It is reversible
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So what are the chosen conditions for the Haber process?
450 C (gives a good rate) and 200 atmospheres (safe and saves money)
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Conditions inside the converter don't give a high yield, but...
Ammonia is removed so that more will form and unreacted gases are recycled
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What elements do plants need? What for?
Nitrogen (chlorophyll, protein), potassium (protein, resisting disease), phosphorus (roots and crops)
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What elements is most important to plants?
Nitrogen
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In what form is nitrogen taken in by plants?
Nitrate ions or ammonium ions
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What is a fertiliser?
Any substance added to soil to make it more fertile
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What types of fertilisers are there?
Natural (animal manure) and synthetic (NH4NO3, K2SO4, (NH4)2SO4, (NH4)3PO4)
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How is ammonium nitrate made?
By reacting with nitric acid NH3+HNO3 = NH4NO3
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How is ammonium sulfate made?
By reacting with sulfuric acid 2NH3 + H2SO4 = (NH4)2SO4
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How are fertilisers dangerous if they get into rivers?
They help algae grow, and when they die bacteria feed on them and use up all the oxygen so fish suffocate
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How are fertilisers dangerous if they get into water supplies?
They get into our bodies and get converted into nitrate ions. They react with haemoglobin so no oxygen is supplied
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What are the sources of sulfur?
Sulfur compounds in fossil fuels, as an elements in underground beds, ores like Pb ore galena
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What are the uses of sulfur?
Sulfuric acid, matches, paper, shampoos, cosmetics
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How is sulfur obtained from oil and gas?
By reacting with oxygen 2H2S+O2= 2S+ 2H2O
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What are the properties of sulfur?
Brittle, yellow, low melting point, insoluble in water, doesn't conduct, 2 allotropes, forms sulfides
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What are the two allotropes of sulfur?
Rhombic sulfur and monoclinic sulfur
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How does sulfur dioxide form?
When sulfur burns in air
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What are the properties of sulfur dioxide?
Colourless, denser than air, strong choking smell, dissolves in water to form sulfurous acid H2SO3 and also kills bacteria
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What are the uses of SO2?
Manufacturing H2SO4, bleaching wool for paper, food preservatives
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By what process is sulfuric acid made?
The Contact process
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What are the raw materials for the Contact process?
Sulfur, air and water OR sulfur dioxide, air and water
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What are the steps in the Contact process starting with sulfur?
1. Sulfur burned in air= sulfur dioxide S+O2= SO2 2. Mixed with more air 3. Passed over four separate beds of catalysts at 450 C. 2SO2+O2=2SO3. It is dissolved in concentrated sulfuric acid=> oleum. 5. Mixed carefully with water= conc. H2SO4
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What is the catalyst used in the Contact process?
Pellets of vanadium V oxide
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What reaction in the Contact process is reversible?
The one between oxygen and sulfur dioxide
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How is the yield increased in the Contact process?
Sulfur trioxide is removed between the last two beds of catalysts
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Why does yield increase when temperature falls in the Contact process?
Because the reaction between sulfur dioxide and oxygen is exothermic
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What is the temperature during the thermite process?
450 C
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How is the heat removed from the catalyst beds during the Contact process?
Pipes of cold water are coiled around the beds to carry heat away. The heat makes the water boil and the steam is used to generate electricity for the plant.
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Why is sulfur dioxide dissolved in acid instead of water?
Because with water a thick dangerous mist of acid forms
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What are the uses of sulfuric acid?
Fertilisers (ammonium sulfate), paints, pigments, dyestuffs, fibres, plastics, soaps, detergents
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Why do you always add sulfuric acid to water and not the other way around?
Because a lot of heat is produced so the acid might splash
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With what will sulfuric acid react?
With metal, metal oxide/hydroxide, carbonate
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Why is concentrated sulfuric acid so dangerous?
It is a very strong dehydrating agent
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What i the carbon cycle?
The movement of carbon between air, water and living organisms. It moves in the form of carbon dioxide.
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How is carbon removed to the atmosphere?
By photosynthesis and dissolving in the ocean
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How is carbon added to the atmosphere?
By respiration and combustion of fossil fuels
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How does CO2 form?
Product of complete combustion, acid+ carbonate, respiration, thermal decomposition
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State the properties of carbon dioxide
Colourless and odourless, slightly soluble in water, denser than air, doesn't support combustion
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What causes the fizz in soft drinks?
Carbon dioxide escaping
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Of what three reactions is cO2 a product of?
1. Combustion of carbon compounds in plenty of air e.g. CH4+ 2O2= CO2+2H2O 2. Respiration 3. Reacting dilute acid with carbonate
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What are the properties of CO?
Forms during incomplete combustion 2CH4+3O2= 2CO+ 4H2O, it's deadly poisonous because reacts with haemoglobin, odourless
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What are the properties of carbonates?
Contain CO3 ions (-2), CaCO3 occurs naturally as chalk/limestone/marble, most of them break down on heating to oxide and carbon dioxide, insoluble except Na, K, and NH4 carbonates
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What are the properties of methane?
Natural gas deposited at the ocean floor, forms where bacteria break down plants without oxygen, cattle/sheep/goat give it out as a waste gas from digestion
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What are the greenhouse gases and what do they do?
CO2 and CH4. They absorb heat in the atoms[here and prevent it from escaping into space
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Describe the process of how greenhouse gases absorb heat.
1. Sun sends out energy as light and UV rays 2. These warm the Earth, some energy is reflected 3. Some heat escapes atmosphere 4. Some heat is absorbed by greenhouse gases so air warms up
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Why is the level of CO2 increasing?
More fossil fuels are burnt
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Why is the level of CH4 increasing?
Because there is an increase in animal farming
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What do greenhouse gases cause?
Global warming
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What is done to attempt to prevent global warming?
People are cutting back on using fossil fuels, clean ways of getting electricity are developed, trying to catch and trap CO2
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What is limestone CaCO3 made of?
Skeletons of dead sea animals
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What is limestone used for?
It's heated to give lime, crushed to give crushed/powdered limestone, and heated with clay to give cement
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What is crushed limestone used for?
Extracting iron from iron core, road building, as chips for concrete
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What is powdered limestone used for?
To neutralise acidity in soil, for flue gas desulfurisation
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What is lime, CaO, used for?
Making steel from iron, neutralising acidity in soil, drying agent in industry
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What is slacked lime, Ca(OH)2, used for?
To neutralise acidity and for flue gas desulfurisation
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What is cement used for?
To make concrete
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What happens to limestone when it is heated?
It breaks down to lime and carbon dioxide
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How is lime made?
A kiln is heated and limestone is fed in at one end. Lime comes out the other end. Reaction is reversible so air is blown in to carry CO2 away.
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How is slacked lime formed?
When water is added to lime
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What is limewater?
Weak solution of Ca(OH)2 which is sparingly soluble in water
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How is cements made?
Mix limestone with clay, heat the mixture strongly in a kiln, add gypsum and grind it into powder
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What is flue gas desulfurisation
Removal of sulfur dioxide from waste gases at power stations
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How is flue gas desulfurisation carried out?
A runny mixture of powdered CaCO3 or Ca(OH)2 is sprayed through waste gases or gases are bubbled through it
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What is the flue gas desulfurisation reaction with slacked lime?
Ca(OH)2 + SO2 = CaSO3 + H2O
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What is gypsum?
Hydrated calcium sulfate
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Other cards in this set

Card 2

Front

What are the properties of hydrogen?

Back

Lightest of all gases, colourless, combines with oxygen to form water which gives out a lot of energy, reduces less reactive metals

Card 3

Front

How do we take in nitrogen?

Back

Preview of the front of card 3

Card 4

Front

What are the properties of nitrogen?

Back

Preview of the front of card 4

Card 5

Front

Why is ammonia the world's second most manufactured chemical?

Back

Preview of the front of card 5
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