Mid Year

• Increasing temperature increases the rate of reaction, as the higher state of kinetic energy cause the particles to collide more frequently and with more energy.
• Increasing concentration of a solution increases the number of particles per unit volume of solution, therefore increasing collisions per second.
• Increasing the surface area of particles also increases the rate of reaction as the frequency of collisions increases.
• Catalysts speed up the rate of reaction by breaking down particles into smaller pieces, reducing the amount of activation energy required to react.
• Rate of reaction = amount of reactant used / time taken to use it
• Rate of reaction = amount of product formed / time
• Fine powders such as flour in mills are highly susceptible to combustion due to the small particle size
• All human diploid cells contain 23 pairs of chromosomes.
• Mitosis is a form of cell division, where the nuclear division of a parent occurs, producing two genetically identical daughter cells. Used to replace old tissue and growth.
• Meiosis is used to make four genetically unique daughter cells and is used in the production of gametes. During meiosis, the chromosome number is halved, and a diploid cell divides to produce four haploid cells. As each gamete produced is genetically unique, each of the offspring will also be unique. This is beneficial for a species as it produces genetic variation.
• A magnetic field is a region where magnetic objects experience a force.
• This magnetic field is strongest at the poles of a magnet.
• An induced magnet is a magnetic material which does not have fixed poles, but can be given poles when placed in a magnetic field temporarily, eg Iron.
• Magnetic fields are generated by moving charges or changing currents.
• Materials can be demagnetised through hammering, heating and being placed in a coil with an AC current going through it. These all rearrange the domains to be random.
• A wave is a regular disturbance transferring energy in the direction of the wave's propagation without transferring matter.
• A transverse wave oscillates at perpendicular angles to the direction of motion.
• A longitudinal wave oscillates in parallel with the direction of motion.
• Transverse waveforms have peaks and troughs.
• Longitudinal wavelengths have compressions and rarefactions.
• A wavelength is the shortest distance between the same two points on two consecutive waves.
• Displacement is the distance from the equilibrium position. At maximum distance, this is the amplitude.
• Frequency is the number of complete waves that pass a point per second. AKA the number of waves per second produced by the source.
• Velocity (m/s) = Wavelength (m) * Frequency (Hz)
• A refraction is a change in speed of a wave when crossing a boundary between two media, resulting in a change of direction.
• The frequency of a wave is not affected by a refraction.
• When entering a denser material, light waves slow down and bend towards the normal.
• Diffraction is the spreading out of waves passing through a narrow gap or across an edge.
• An image formed in a plane mirror is the same size, same side of the mirror but is an inverted version of the object.
• Non metals are formed at the positive electrode and metals or hydrogen are formed the the negative electrode.
• Electrolysis is the breakdown of a molten or aqueous ionic compound using electricity.
• An example of a transverse waves is in a string or a wave on a water surface.
• In order of longest to shortest wavelength, Gamma, X ray, Ultra Violet, Visible, Infrared, Microwaves, Radio.
• Speed of electromagnetic waves in a vacuum is 3x10^8 m/s
• 400-700 nanometers frequencies can be picked up by the human eye.
• All electromagnetic waves are transverse waves, travel at the same speed and can travel through a vacuum.
• The speed of sound is fastest in solids and slowest in gases.
• a gene is the length of DNA on a chromosome to produce a specific protein.
• Meiosis is a form of nuclear division that produces four gamete daughter cells that have half the number of chromosomes, therefore being haploid cells.
• inheritance is the transmissions of genetic information for generation to generation