QUESTION 2     This question is about ions and ionic compounds.   2.1   Choose from the following list of ions to answer the questions.   Br-          Ca2+               Cl –                  Cr 3+               Cu 2+ K +                Li +               Na+                 SO32-           SO42-     Each ion may be used once, more than once or not at all. State which ion:     a gives a lilac colour in a flame test. [1]   b forms a grey-green precipitate with aqueous ammonia. [1]   c forms a white precipitate with aqueous sodium hydroxide. [1]   d forms a cream precipitate with acidified aqueous silver nitrate. [1]   e forms a white precipitate with acidified aqueous barium nitrate. [1] 2.2   Describe how to do a flame test on a sample of a salt. [2] 2.3   Magnesium phosphate contains magnesium ions, Mg2+ , and phosphate ions, PO43- . Deduce the formula of magnesium phosphate. [1]       [8]  

 1.25 A student is asked to measure the time taken for 0.4 g of magnesium carbonate to react completely with 25.0 cm3 of dilute hydrochloric acid. Which pieces of apparatus does the student need?   (1)

1.1 Which diagram illustrates diffusion? (1)     Right-click on the button to open the data booklet in a new tab.       

1.8 The diagram shows an unsuccessful experiment to nickel plate a pan. What change is necessary to nickel plate the pan?   (1)   Right-click on the button to open the data booklet in a new tab.    

1.12 An aqueous solution of copper (II) sulphate was made by adding excess copper (II) oxide to dilute sulphuric acid. The mixture was heated, stirred, and then filtered. (1)   Right-click on the button to open the data booklet in a new tab.        What was the pH of the acid before adding the copper (II) oxide and of the solution after filtration?     pH of acid before adding copper (II) oxide pH of solution after filtration A greater than 7 7 B greater than 7 less than 7 C less than 7 7 D less than 7 greater than 7

 1.32 Calcium carbonate reacts with dilute hydrochloric acid. The equation for the reaction is shown. CaCO3 + 2HCl — > CaCl 2 + H2O + CO2 1.00 g of calcium carbonate is added to 50.0 cm3 of 0.0500 mol / dm3 hydrochloric acid. Which volume of carbon dioxide is made in this reaction?   (1)

1.34 Which is a chemical change? (1)

 1.40 Four different food colourings are analysed using chromatography. The results are shown on the chromatogram. The diagram is not drawn to scale. Which food colouring contains a component with an Rf value of 0.3? (1)   Right-click on the button to open the data booklet in a new tab.       

1.36 Which pair of elements reacts together most violently? (1)

1.14 Three gas jars contain carbon dioxide, hydrogen, and oxygen. Which one of the following tests could be used to discover which gas is in each jar? (1)