Doppler Shift of Sound The whistle of a train or the siren of an ambulance appears to decrease in frequency (sounds lower in pitch) as it moves further away from you This frequency change due to th...
Properties of Transverse & Longitudinal Waves In mechanical waves, particles oscillate about fixed points The direction of oscillations with regards to the direction of wave travel determine wh...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.3.2 Halogens & Alkanes Halogens & Alkanes In a substitution reaction, one atom is swapped with another atom Alkanes undergo a substitution reaction...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.3.1 Alkanes The Alkanes Alkanes are a group of?saturated?hydrocarbons The term saturated means that they only have single carbon-carbon bonds, there are no...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.2.4 Cracking Cracking Saturated molecules contain?single?bonds only whereas unsaturated molecules contain?double?bonds between their carbon atoms Alkanes?a...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.2.3 Nitrogen Oxides & Sulfur Dioxide Formation of Nitrogen Oxides Nitrogen Oxides These compounds (NO and NO2) are formed when nitrogen and oxygen reac...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.2.2 Combustion Fuels & Combustion The combustion of fossil fuels is the major source of atmospheric pollution Fossil fuels include:?coal,?oil,?natural ...
Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 4.2.1 Crude Oil & Fractional Distillation Crude Oil & Fractional Distillation Crude oil as a mixture is not a very useful substance but the different...
Wave Intensity Progressive waves transfer?energy The amount of energy passing through a unit area per unit time is the?intensity?of the wave Therefore, the?intensity?is defined as?power per unit ar...
