Free Industrial Chemistry MCQs with Answers

• A. the joining together of many small repeating units called monomers
• B. the breaking of a large molecule into small units
• C. mixing two liquids without any reaction
• D. heating a metal until it melts

Explanation: Thousands of monomer units link together to form a chain whose properties are quite different from those of the monomer, so gaseous ethene…

• A. condensation polymerisation
• B. addition polymerisation
• C. hydrolysis
• D. esterification

Explanation: The double bond of each ethene molecule opens and the units join end to end with no atoms lost, so the empirical formula of the polymer is…

• A. no by product is formed
• B. the monomers contain double bonds that open
• C. a small molecule such as water or hydrogen chloride is eliminated at each linkage
• D. the polymer is condensed from a gas

Explanation: A diamine and a dicarboxylic acid react so that an amide linkage forms and water is expelled at each join, which is why the polymer…

• A. softens every time it is heated and can be remoulded
• B. dissolves readily in water
• C. conducts electricity
• D. sets permanently on first heating because cross links form between the chains

Explanation: Covalent cross links lock the chains into a rigid three dimensional network, so the material cannot be softened and remoulded and simply…

• A. chloroethene
• B. chloroethane
• C. ethene
• D. phenol

Explanation: Chloroethene, also called vinyl chloride, has the double bond needed for addition polymerisation and carries the chlorine that gives PVC…

• A. Polystyrene
• B. Cellulose
• C. Nylon
• D. Teflon

Explanation: Cellulose is a natural condensation polymer of beta glucose and is the main structural material of plant cell walls, as are starch…

• A. dissolve in rainwater and pollute rivers
• B. react violently with air
• C. are non biodegradable, because their inert carbon backbone resists attack by microorganisms
• D. release oxygen as they age

Explanation: The saturated carbon chain has no polar groups for enzymes to attack, so plastic waste persists in landfill and in the oceans for…

• A. melting the two surfaces together
• B. forming intermolecular forces or chemical bonds with both surfaces while cohering strongly within itself
• C. removing all air from between the surfaces only
• D. converting one surface into the other

Explanation: A good adhesive must both adhere, sticking to each surface, and cohere, holding together internally, and it usually starts as a liquid so…

• A. one tube contains the solvent that evaporates
• B. the two components are the same substance at different concentrations
• C. mixing lowers the temperature of the joint
• D. the resin and the hardener react together to form cross links, setting the adhesive

Explanation: Setting is a chemical reaction between the resin and a hardener that builds a rigid cross linked network, so the two must be kept apart…

• A. cooling and solidifying, with no chemical change
• B. reacting chemically with the surface
• C. absorbing water from the air
• D. releasing carbon dioxide

Explanation: The adhesive is applied molten, flows into the surface irregularities and then simply freezes as it cools, so the change is physical and…

• A. is always black
• B. is insoluble and sits on the surface as fine particles
• C. is soluble in the medium and becomes attached to the fibre
• D. contains no colour at all

Explanation: A dye dissolves and bonds to the fibre by ionic, hydrogen or covalent bonds, so the colour becomes part of the material and resists…

• A. auxochrome
• B. chromophore
• C. monomer
• D. catalyst

Explanation: A chromophore is an unsaturated group such as the azo linkage or a nitro group whose delocalised electrons absorb visible light, and the…

• A. N=N joining two aromatic rings
• B. C=O
• C. OH only
• D. COOH

Explanation: The azo group links two aromatic systems into one extended conjugated network, and the resulting absorption in the visible region makes…

• A. bleach the fabric before dyeing
• B. dissolve the dye in water
• C. remove excess dye after the process
• D. fix a dye to a fibre it would not otherwise bind to, usually by forming a metal complex

Explanation: A mordant, commonly a salt of aluminium, chromium or iron, is absorbed by the fibre first and then forms a coordination complex with the…

• A. two amino acids
• B. a diol with a dicarboxylic acid
• C. two molecules of ethene
• D. glucose units

Explanation: Ethane-1,2-diol reacts with benzene-1,4-dicarboxylic acid so that ester linkages form and water is eliminated, giving a polymer used for…

• A. tetrafluoroethene
• B. chloroethene
• C. propene
• D. styrene

Explanation: Every hydrogen of ethene is replaced by fluorine, and the resulting carbon to fluorine bonds are so strong and the surface so non polar…

• A. carbon black
• B. sulphur, which forms cross links between the polymer chains
• C. water under pressure
• D. sodium hydroxide

Explanation: Short chains of sulphur atoms bridge the polyisoprene chains, so they can no longer slide past one another permanently and the rubber…

• A. are always coloured
• B. are made from natural materials
• C. cannot be melted and reshaped once their cross links have formed
• D. dissolve in water

Explanation: The permanent covalent network of a thermoset means heating it decomposes the material rather than softening it, so it can only be ground…

• A. Bakelite
• B. Polyethylene terephthalate
• C. Urea formaldehyde resin
• D. Melamine resin

Explanation: Polyethylene terephthalate is a thermoplastic polyester that is clear, tough and impermeable to carbon dioxide, and because it melts…

• A. at least two different functional groups
• B. a benzene ring
• C. a hydroxyl group
• D. a carbon to carbon double bond

Explanation: The pi bond opens so that each unit can bond to the next with nothing eliminated, which is why ethene, propene, chloroethene and styrene…