AQA A Level Physics复习笔记2.1.3 Strong Nuclear Force
Strong Nuclear Force In the nucleus, there are electrostatic forces between the protons due to their electric charge and gravitational forces due to their mass Comparatively, gravity is a ve...
AQA A Level Physics复习笔记2.1.2 Nucleon & Proton Number
AZX Notation A nuclide is a group of atoms containing the same number of protons and neutrons For example, 5 atoms of oxygen are all the same nuclide but are 5 separate atoms Atomic s...
AQA A Level Physics复习笔记1.2.3 Determining Uncertainties from Graphs
Using Error Bars The uncertainty in a measurement can be shown on a graph as an error bar This bar is drawn above and below the point (or from side to side) and shows the uncertainty in that...
AQA A Level Physics复习笔记1.2.2 Calculating Uncertainties
Uncertainty There is always a degree of uncertainty when measurements are taken; the uncertainty can be thought of as the difference between the actual reading taken (caused by the equipment...
AQA A Level Physics复习笔记1.1.3 Estimating Physical Quantities
Orders of Magnitude A quantity is an “order of magnitude” larger than another quantity if it is about ten times larger Similarly, two orders of magnitude would be 100 times larger, or 102 &n...
AQA A Level Physics复习笔记1.1.2 Powers of Ten
Powers of Ten Physical quantities can span a huge range of values For example, the diameter of an atom is about 10–10 m (0.0000000001 m), whereas the width of a galaxy may be about 1021 m (1...
AQA A Level Chemistry复习笔记8.3.4 Required Practical 12
Separation of species by TLC Required practical 12: Separation of species by thin-layer chromatography This practical covers two key laboratory skills use thin-layer or paper chromatography safely ...
AQA A Level Chemistry复习笔记8.3.3 Testing Aldehydes & Ketones
Tollens' Reagent Testing Distinguishing Between Aldehydes & Ketones Weak oxidising agents can be used to distinguish between an aldehyde and a ketone The aldehyde will be oxidised to a c...
AQA A Level Chemistry复习笔记8.3.2 Required Practical 10b
Preparation of an Ester This required practical covers the following mandatory skills use water bath or electric heater or sand bath for heating use laboratory apparatus for a variety of exp...
