chemicals and their manufacture

Question 1

An alkali is a compound that ………… to give a solution with a pH higher than ….

Answer 1

An alkali is a compound that dissolves to give a solution with a pH higher than 7.

Question 2

Alkalis contain an important property that allows them to neutralise acids. When this what is made?

Answer 2

Alkalis contain an important property that allows them to neutralise acids. When this happens a salt is made.

acid + alkali → salt + water

Question 3

What is the formula when an alkali neutralises an acid?

Answer 3

acid + alkali → salt + water

Question 4

Common examples of alkalis include ….

Answer 4

Common examples of alkalis include soluble hydroxides and carbonates. .

Question 5

When each of these alkalis reacts with an acid, there is a difference in the products that are formed. What happens when an alkaline hydroxide reacts with an acid, ?

Answer 5

Salt and water are formed.

Question 6

What is the the general equation for when an alkaline hydroxide reacts with an acid, and salt and water are formed.

Answer 6

This is shown by the general equation:

Alkaline hydroxide + acid → salt + water

Question 7

What is the general equation for when sodium hydroxide reacts with hydrochloric acid

Answer 7

Sodium hydroxide + hydrochloric acid → sodium chloride + water

Question 8

When an alkaline carbonate reacts with an acid, salt and water are again formed but there is also a third product, - what is it?

Alkaline carbonate + acid → salt + water + carbon dioxide

Answer 8

carbon dioxide.

Question 9

What is the general equation for when When an alkaline carbonate reacts with an acid, salt and water and also carbon dioxide are produced

Answer 9

Alkaline carbonate + acid → salt + water + carbon dioxide

Question 10

how is the name of the salt found ?

Answer 10

the first part of the name comes from the metal in the alkali used, the second comes from the acid used

Question 11

What is the leBlanc process?

Answer 11

The LeBlanc process was a process invented to make alkali sodium carbonate on a large scale. Sodium chloride was mixed with sulfuric acid before being heated with charcoal and limestone.

Question 12

In what why was the LeBlanc process very polluting

Answer 12

The process itself was very polluting. It released huge volumes of an acid gas (hydrogen chloride) into the air that wrecked the surrounding land. It also produced large amounts of solid waste that slowly released the toxic gas hydrogen sulfide. This gas has a characteristic smell of rotten eggs

Question 13

The effect of pollution from Alkali sodium carbonate manufacture became very extensive. This pressured the government into taking action.

The industry was required to reduce the level of hydrogen chloride gas released into the atmosphere. How was this done

Answer 13

The first response was to dissolve the hydrogen chloride in water, creating hydrochloric acid that at the time had no use.

A more useful method of disposal was discovered. Hydrogen chloride could be oxidised to form chlorine, a useful chemical by mixing it with oxygen and passing the mixture over a hot copper containing catalyst.

Question 14

Water that has been contaminated with certain types of microorganisms can be very unsafe.What can it cause?

Answer 14

Water that has been contaminated with certain types of microorganisms can be very unsafe. It can cause diseases such as typhoid, cholera and dysentery.

Question 15

What was done to water in the early part of the twentieth century, and had a dramatic effect of reducing many waterborne diseases and so increasing public health.

Answer 15

Treating water with chlorine kills microorganisms that may exist in domestic water. supplies. This is known as chlorination

Question 16

There may be disadvantages of consuming water that has been treated with chlorine. What are these?

Answer 16

There may be disadvantages of consuming water that has been treated with chlorine. When water is treated with chlorine some disinfection byproducts called tirhalomethanes (THMs) can form. They form when chlorine reacts with naturally occurring organic matter such as leaves.

Question 17

There is a notion that tirhalomethanes (THMs) can cause …….. Has any firm evidence has been found to support this theory.

Answer 17

cancer - no firm evidence

Question 18

Brine is a solution of sodium chloride ……and water (H2O).

Answer 18

Brine is a solution of sodium chloride (NaCl) and water (H2O).

Question 19

What is involved in the process of electrolysis

Answer 19

The process of electrolysis involves using an electric current to bring about a chemical change and make new chemicals.

Question 20

The electrolysis of brine is a large-scale process used to manufacture chlorine from salt. Two other useful chemicals are obtained during the process - what are they?

Answer 20

sodium hydroxide (NaOH) and hydrogen (H2).

Question 21

name 3 uses of chlorine

Answer 21

disinfectant and purifier
manufacture of hydrochloric acid

making plastics

Question 22

name 3 uses of sodium hydroxide

Answer 22

processing food products
removing pollutants from water

manufacture of paper

Question 23

name 2 uses of hydrogen

Answer 23

manufacture of hydrochloric acid

potential as a pollution-free fuel

Question 24

What are the Environmental impacts of the electrolysis of brine on a large scale?

Answer 24

Environmental impacts of the electrolysis of brine on a large scale must be considered. The process uses a lot of electricity that is mainly produced by the burning of fossil fuels. During the actual process of electrolysis, metal must be in contact with the solution of brine. A metal commonly used is mercury which is toxic. Some mercury escapes into the solution and into the environment.

Question 25

What is PVC?

Answer 25

Polyvinyl chloride (PVC) is a widely used plasticThis synthetic polymer is relatively cheap and easy to mould. There are different types of PVC that are manufactured, serving a range of uses from underground pipes carrying water, gas and sewage to thinner films used in packaging.

Question 26

What does PVC contain?

Answer 26

carbon, hydrogen and chlorine.

Question 27

What are Plasticers used for ? How does it work?

Answer 27

Plasticisers are used to make a material like PVC softer and more flexible. They are small molecules that can dissolve into liquids that come into contact with them.

Question 28

What is an LCA? And what can it be used for?

Answer 28

A life cycle assessment, or LCA, can be used to assess the environmental impact of the manufacture and use of different materials and products.

Question 29

What are the Key features of a life cycle assessment?

Answer 29

The key features of a life cycle assessment include the following factors:
the main requirements for energy input
the environmental impact and sustainability of making the materials from natural resources
the environmental impact of making the product from the material
the environmental impact of using the product
the environmental impact of disposing of the product by incineration, landfill or recycling.

Question 30

It is possible to make a product from different materials. A window frame, for example can be made from wood or uPVC. What will the life cycle assessment for a product will depend on ?

Answer 30

The life cycle assessment for a product will depend on the material that it is made from.

Question 31

A life cycle assessment can be used to compare and evaluate the impact of ……………………………..?

Answer 31

the use of different materials for the same job

the use of the same material for different jobs.

Question 32

It is possible to make a life cycle assessment of a material. The outcome of this life cycle assessment will depend on what?

Answer 32

a consideration of the factors involved in the production of the material
a consideration of the factors that involve each of the products that are made from this material.

Question 33

How is PVC made?

Answer 33

It is produced by the process of polymerisation. Molecules of vinyl chloride monomers combine to make long chain molecules of polyvinyl chloride.

Question 34

Why is PVC useful?

Answer 34

It is relatively cheap and easy to mould - different types of PVC serve a range of uses from underground pipes carrying water, gas and sewage to thinner films used in packaging.

Question 35

What are the 3 main stages of an LCA (life cycle assessment)?

Answer 35

A life cycle assessment, or LCA, is a study of the stages in the life of a manufactured product. The articles that we use have three main life stages: manufacture, use and disposal

Question 36

What can happend when plastic toys are chewed e.g by a child?

Answer 36

the plasticiser may be dissolved by the saliva of the child and possibly ingested.

Question 37

Some argue that phthalates should be banned due to evidence linking them with …………………………. such as ………..

Answer 37

Some argue that phthalates should be banned due to evidence linking them with health problems such as cancer.

Question 38

Some plasticisers have been banned by regulators where?

Answer 38

in Europe and the USA.