Sci Rev

• Like charges repel and unlike charges attract. This is called electrostatic attraction.
• Friction causes electrostatic charges to repel each other, causing the electrons to move away from the metal surface.
• An electric field is a region of space where there is a force on an electric charge.
• Current is the rate of flow of charge through a circuit, measured in amperes (A). The equation for this is I = Q/t, where I is current, Q is the coulombs of charge and t is time in seconds.
• Electric power is the rate at which energy is transferred by electricity, measured in watts (W).
• Electro motive force is defined as the energy supplied by a source in driving a unit of charge around a circuit.
• A magnet that is free to swing will align itself with the Earth's magnetic field.
• When iron, cobalt and nickel come into contact with a permanent magnet, they temporarily magnetise as the domains within the metal are forced in one direction. Steel can be permanently magnetised as it's domains do not move again once they're set.
• Magnetic field lines go from the north end to the south end.
• In the right-hand grip rule, the fingers represent the direction of the field and the thumb the current.
• A DC motor works by having a coil of wire rotating around a magnetic field. Electricity flows through when the coil is not horizontal, then using a split-ring commutator, it can rotate fully.
• The equation for voltage and number of turns on a transformer is (Vp/Vs = Np/Ns)
• Sulfur is used in the manufacturing of sulfuric acid.
• $S +$$O^2 =$$SO^2$
• $2SO^2 +$$O^2 =$$2SO^3$
• $H^2SO^4+$$SO^3 =$$H^2S^2O^7$
• $H^2S^2O^7 +$$H^20 =$$2H^2SO^4$
• Rate of reaction can be measured by reacting a mixture in a flask, producing a gas that is measured in another flask.
• Rate of reaction can be measured by measuring the amount to time taken for a reactant to disappear.
• The rate of reaction can be measured by the amount of time taken for a solution to turn opaque when reacted.
• A reaction can only occur when two molecules collide with sufficient energy.
• Increasing the temperature of reactants increases the rate of reaction as the particles have more kinetic energy, meaning more collide with sufficient energy.
• Increasing the surface area of the reactants by grinding them into a fine powder increases the rate of reaction as more particles are able to collide with other particles.
• Increasing the concentration or pressure of reactants increases the rate of reaction as there are more particles within a smaller space.
• The presence of a catalyst also speeds up the rate of reaction without being used up in the reaction by reducing the activation energy required to react.
• A redox reaction is a reaction that involves the transfer of electrons between two or more substances.
• A redox reaction is a reduction-oxidation reaction. One of these processes cannot happen with the other.
• Reduction is when an atom gains one or more electrons
• Oxidation is when an atom loses one or more electrons
• LEO GER stands for "Loss of Electrons is Oxidisation" and "Gain of Electrons is Reduction"
• In a redox reaction, there must be at least one oxidising agent (electron acceptor) and one reducing agent (electron donor)