Chemistry revision Different substances and their properties 0.0 / 5 ? ChemistryRate of reactionGCSEAQA Created by: melisaCreated on: 18-09-13 22:26 Which of the statements below is correct? Ionic bonds are forces of attraction between oppositely-charged ions. 1 of 13 Why do ionic compounds have high melting and boiling points? Ionic compounds have high melting and boiling points because there are strong bonds between their ions. 2 of 13 In what physical state or states do ionic substances conduct electricity? Ionic substances conduct electricity when they are liquid or dissolved in water 3 of 13 When a substance with a simple molecular structure boils, which bonds are broken? When a molecular substance boils, the bonds broken are intermolecular bonds. 4 of 13 Which of the following statements is true of substances with a simple molecular structure? Substances with a simple molecular structure have low melting points and do not conduct electricity. 5 of 13 Which of the following statements is true of diamond? In diamond, each carbon atom is covalently bonded to four other carbon atoms. 6 of 13 Which of the following statements is true of graphite? In graphite, each carbon atom is covalently bonded to three other carbon atoms. 7 of 13 Why are metals good conductors of electricity? Metals are good conductors of electricity because they contain electrons that are free to move. 8 of 13 What is the approximate size of a typical nanoparticle? 50 nm 9 of 13 How many nanometres are there in a metre? One billion 10 of 13 Which statement about nanoparticles is correct? Their properties are usually different from the substance in bulk. 11 of 13 Why are titanium dioxide nanoparticles used in sunblock creams? Titanium dioxide nanoparticles are used in sunblock creams because they block ultraviolet light but do not reflect visible light. 12 of 13 Which statement about nanoparticles is correct? They have a large surface area compared to their volume. 13 of 13
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