Quiz

• Explain, in terms of electrons, why these gases are inert.

  -full outer shell

  -they don’t lose, gain, transfer, share electrons
• (a) Describe the test to show that a gas is oxygen.

  -glowing splint

  -if the glowing splint relights, oxygen is present
• Explain the effect on the rate of reaction of using smaller marble chips.

  Smaller marble chips have a larger surface area so more frequent successful collisions, increases rate of reaction.
• Which change would make the rate of reaction slower?

  B using acid of a lower concentration
• State the type of structure and bonding in silicon dioxide.

  Giant covalent
• Some sunscreens contain nanoparticles of titanium dioxide.

  Explain why nanoparticles of titanium dioxide are used in some sunscreens.

  They block UV reaching skin, preventing skinburns.
• State how the amount of stone added to the mixture affects the compressive strength of concrete.

  Strength decreases as the amount of stone added increases
• What is true statement of nanoparticles?

  D nanoparticles are larger than atoms and molecules
• Explain a safety precaution that should be taken when using a substance with the hazard symbol shown in Figure 6.

  -corrosive so wear gloves and goggles
• Substance K has the formula AgNO. Give the name of substance K.

  Silver nitrate
• State one property of poly(ethene) that makes it a suitable material to make a container for storing substances.

  Unreactive
• student tests a solid for chloride ions.

  The student uses the following method.

  step 1 dissolve a small amount of the solid in water step 2 add some dilute hydrochloric acid step 3 add a few drops of a solution of K

  step 4 observe whether or not a white precipitate forms.

  This method to show whether the solid contains chloride ions will not work.

  Explain a change that needs to be made to step 2 to allow this method To work

  Add a few drops of nitric acid instead.
• Sodium carbonate, Na,CO, is reacted with dilute hydrochloric acid.

  Complete and balance the equation for this reaction.

  Na2CO3 + 2HC →

  2NaCl + H2O +CO2
• State two features of an homologous series.

  Same general formula

  Same chemical properties