7575004
Descrição
FlashCards por miranda ferg, atualizado more than 1 year ago
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Criado por miranda ferg
quase 8 anos atrás
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| Questão | Responda |
| what is electrolysis | Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity |
| what are ionic substances | Ionic substances contain charged particles called ions. For example, lead bromide contains positively charged lead ions and negatively charged bromide ions. |
| why is the ionic substance dissolved in water or made molten | For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted |
| what happens at the negative electrode (cathode) | Positively charged ions (cations) move to the negative electrode during electrolysis. They receive electrons and are reduced. |
| what happens at the positive electrode (anode) | Negatively charged ions (anions) move to the positive electrode during electrolysis. They lose electrons and are oxidised |
| what is an electrolyte | The substance that is broken down is called the electrolyte |
| what is bauxite | Aluminium ore is called bauxite. The bauxite is purified to yield a white powder - aluminium oxide - from which aluminium can be extracted. |
| what is cryolyte | Aluminium oxide has a very high melting point (over 2000°C) its expensive to melt. Instead, it is dissolved in molten cryolite - an aluminium compound with a lower melting point than aluminium oxide. cryolite reduces some of the energy costs in extracting aluminium. |
| how do you write a half equation | Electrons are shown as e- in half-equations. A half-equation is balanced by adding, or taking away, a number of electrons equal to the total number of charges on the ions in the equation. 1. Write the formulae of the reactant and product. Cl- → Cl2 2. Adjust the number of ions, if needed. 2Cl- → Cl2 3. Count the number of charges. Add enough electrons so that both sides have the same total number of charges. 2Cl- → Cl2 2e- |
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