Metallic bonding is the electrostatic force of attraction between ____ charged ions and ____ electrons. Metallic elements are ____ of electricity because they contain delocalised electrons. metal + oxygen —> ____ metal + water —> ____ + H2 metal + dilute acid —> ____ + hydrogen Metals can be arranged in order of ____ by comparing the rates at which they react. ____ is at the top of the reactivity series, ____ is at the bottom. Reduction is a ____ of electrons by a reactant in any reaction. Oxidation is a ____ of electrons by a reactant in any reaction. In a ____ reaction, reduction and oxidation take place at the same time. During the extraction of metals, metal ions are ____ forming metal ____. The method used to extract a metal from its ore depends on the position of the metal in the ____. Extraction of metals Methods used are: ____ (for extraction of Ag, Au and Hg), heating ____ (for extraction of Cu, Pb, Sn, Fe and Zn) or ____ (for extraction of more reactive metals including aluminium) Electrolysis is the decomposition of an ionic compound into its elements using electricity. A ____ supply must be used if the products of electrolysis are to be ____. Positive ions gain electrons at the ____ electrode and negative ions lose electrons at the ____ electrode. A simple electrochemical cell can be made by placing two ____ in an ____. We call this a ____. Electrically conducting solutions containing ____ are known as electrolytes. Another type of cell can be made using two ____ An ____ can be used to link the half-cells of an electrochemical cell. ____ can move across the bridge to complete an electrical circuit. Electrons move through the ____. A graphite rod can be used as the electrode in such half-cells. Different pairs of metals produce different ____. These voltages can be used to arrange the elements into an ____ series. The further ____ elements are in the electrochemical series, the greater the voltage produced when they are used to make an electrochemical cell. Electrons flow in the circuit from the species ____ in the electrochemical series to the one ____ in the electrochemical series. Plastics are examples of materials known as ____. Polymers are ____ chain molecules formed by joining together a large number of small molecules called ____. Growing plants require ____, including compounds containing nitrogen, ____ or potassium. Fertilisers are substances which restore elements, ____ for healthy plant growth, to the soil. Ammonia and nitric acid are important compounds used to produce ____, nitrogen- containing salts that can be used as fertilisers. Ammonia is a pungent, clear, colourless gas which dissolves in water to produce an ____ solution. Ammonia solutions react with acids to form soluble salts. ammonia + acid —> ammonium salt + H2O The ____ process is used to produce the ammonia required for fertiliser production. N2 (g) + 3H2 (g) —> 2NH3 (g) At ____temperatures the forward reaction is too slow to be economical. If the temperature is ____, the rate of reaction increases but, as the temperature increases, the backward reaction becomes more dominant. An ____ catalyst is used to increase reaction rate. Ammonia is the starting material for the commercial production of ____ The ____ process uses ammonia, oxygen and water to produce nitric acid. A ____ catalyst is used in this process. Radioactive decay involves changes in the ____ of atoms. Unstable nuclei (radioisotopes) can become more ____ nuclei by giving out ____, beta or gamma radiation. Alpha particles (α) consist of two ____ and two neutrons and carry a double ____ charge. They have a range of only a few centimetres in air and are stopped by a ____. Alpha particles will be attracted towards a ____ charged plate. Beta particles (β) are ____ ejected from the ____ of an atom. They are able to travel over a metre in air but can be stopped by a thin sheet of ____. Beta particles will be attracted towards a ____ charged plate. Gamma rays (γ) are ____ emitted from within the ____ of an atom. They are able to travel great distances in air. They can be stopped by barriers made of materials such as ____. Gamma rays are ____ deflected by an electric field. Half-life is the time for half of the nuclei of a particular isotope to ____. The half-life of an isotope is a ____, unaffected by chemical or physical conditions. Radioactive isotopes can be used to ____ materials. Radioisotopes have a range of uses in medicine and in industry. isotopes used inside the body should have a ____ half life to minimise damage to ____. Isotopes used in industry should have a ____ half life so that they do not need to be ____ often. The choice of isotopes should reflect the material it needs to pass through. ____ radiation is useful in smoke detectors because they are ____ absorbed by smoke particles The choice of isotopes should reflect the material it needs to pass through. ____ radiation is useful in tracers detectors because it can pass through bone and tissue.

national 5 chemistry - unit 3

oleh
Cetakan
Benamkan

Papan mata

Gaya visual

Pilihan

Tukar templat

Pulihkan autosimpan: ?