C6- electrolysis 💧

• electrolysis, is the chemical effect of electricity • on ionic compounds, • causing them to break up into simpler substances [usually elements]

• the anode, is the positive electrode that is connected to the positive of the battery.

• the cathode, is the negative electrode, that is connected to the negative of the battery

• an electrode, is a metal rod that is placed in the liquid; through which electricity passes. • electrodes, can be made be out of carbon [graphite], • platinum and copper etc.

• PANIC- positive is anode, negative is cathode.

• the electrolyte, is a [aqeous] solution • or molten solid [liquid] of an ionic substance • , through which the electrical current passes. • The mass of this ionic substance will decrease during electrolysis, as it is split up.

• an ionic substance, is a compound that is held together by ionic bonds. • ; Ionic bonds are created when one element [usually a metal] loses an electron to a non metal.

• solid ionic compounds can’t be electrolysed • This is because the ions are locked in place, • due to being held by strong electrostatic forces of attraction • and therefore, they’re not free to move.

• solid ionic compounds can’t be electrolysed • ; when an ionic compound is melted or dissolved in water, the forces of attraction are broken, and the ions are free to move. • therefore, when an ionic compound is melted or dissolved in water [molten/liquid], they can be electrolysed and conduct electricity. • [scientists call these liquid or solution electrolytes]

• during electrolysis, ions become atoms at the electrodes: • because positive metal ions are attracted to the negative electrode, where they gain electrons and form metal atoms [cation] • ; negative non-metal ions are attracted to the positive electrode, where they lose electrons and form non-metal atoms [anions]

• in the electrical charge carried through wires, the electrical charge is carried by electrons. • This is because, electrons have a negative charge • due to their behavior in an electric field. • ; the electrical charge carried though electrolyte, is carried by ions • because, the number of electrons don’t equal the number of protons in the atom or molecule

• lead bromide, contains two ions: the positive lead ion and the negative bromide ion.

• in electrolysis, there are two electrodes made of a conducting material [graphite or a metal]. • the negative electrode is known as the cathode, and is attached to the negative terminal of a power pack. [it’s covered with electrodes from the power pack] • ; the positive electrode, is called the anode and is connected to the positive terminal of the power pack. [it has a lack of electrons]

• the positive lead ions are attracted to the negative electrode because, opposite charges attract. • ; the negative bromide ion, is attracted to the positive electrode.

• the positive lead ions are attracted to the negative electrode because, opposite charges attract. • The lead ion will now gain two electrons, to form lead atoms and this is a reduction reaction [as it gains electrons] • ; the negative bromide ion, is attracted to the positive electrode. • The negative bromide ion, will lose one electron to form bromide atoms and this is an oxidation reaction [as it loses electrons].

• bromide atoms will pair to form a bromide molecule

• opposites attract [and like charges repel] because matter wants to possess neutral state. • a negatively charged ion wants to give away its electrons to become neutral therefore it attracts positive charge towards it. • ; a positively charged ion requires electrons to become neutral, that is why it moves towards negative charge.

• opposites charges attract [and like charges repel] because matter wants to possess neutral state.

• the electrolyte must be a liquid, so the ions are free to move to the electrodes

• ions move in the electrolyte because, opposite charges attract. • positive ions [cations] are attracted to the negative cathode. • and negative ions [anions] are attracted to the positive anode.

• cations, are positive ions that are attracted to the negative cathode. • ; anions are negative ions that are attracted to the positive anode.

• the word equation, to show the electrolysis of molten lead bromide is: • PbBr2( l ) Lead bromide ⟶ Pb ( s ) Lead + Br 2 ( g ) Bromine gas . • the products are lead bromine gas; the reactants is lead bromide.

• electrolysis can be described in terms of the movement of ions: • This is because, passing an electric current through electrolytes, causes the ions to move to the electrodes • as the free moving ions in electrolytes, are attracted to the oppositely charged electrodes- that are connected to the dc supply

• when writing half -equations, if there is a positively charged ion, the electron goes before the arrow to balance the charges