Author: Anonymous

1.26 A covalent molecule M contains four shared pairs of electrons. What is M?   A hydrogen chloride, HCl B methane, CH4 C ammonia, NH3 D water, H2O

  QUESTION 7   Insoluble salts can be made by precipitation reactions. A student mixed solutions of some soluble salts. The results the student obtained are shown in the table.   Right-click on the button to open the data booklet in a new tab.        All sodium salts are soluble in water. Use only results from the table to answer the following questions.   7.1 Write the chemical equation for the reaction in which silver carbonate is formed. [2] 7.2 Name an insoluble cobalt salt. [1] 7.3 Name an insoluble yellow lead salt. [1]     [4]

1.34 Which is a chemical change?

1.38 River water contains soluble impurities, insoluble impurities, and bacteria. River water is made safe to drink by filtration and chlorination. Which statement is correct?

  QUESTION 3 3.1   Chlorine exists as a number of different isotopes. What is meant by the term isotopes? [2] 3.2   A chloride ion has a symbol shown.   Right-click on the button to open the data booklet in a new tab.            a How many neutrons are contained in this chloride ion? [1]   b How is a chloride ion formed from the chlorine atom? [1]   c Which atom forms an ion with a 1+ charge and has the same number of electrons as Cl-? [1]       [5]  

1.27 An isotope of chromium has an atomic mass of 52g.mol-1 . Which statement about an atom of this isotope of chromium is correct?

1.28 During the electrolysis of concentrated hydrochloric acid, gases are produced at both electrodes. Which statement describes the test result for the gas collected at the negative electrode?

1.19 Which statement about aluminium is not correct?

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?

1.39 Which physical property is used to separate the nitrogen and oxygen from air?