Atoms: Key Terms The atomic number (or proton number) is the number of protons in the nucleus of an atom and has the symbol Z The atomic number is also equal to the number of electrons that are pre...
Mass & Charge Distribution The mass of an atom is concentrated in the nucleus, because the nucleus contains the heaviest subatomic particles (the neutrons and protons) The mass of the electron ...
Titrations Volumetric analysis is a process that uses the volume and concentration of one chemical reactant (a standard solution) to determine the concentration of another unknown solution The tech...
随着留学申请人数的不断增加，竞争也愈发激烈，留学早已陷入内卷不停的怪圈之中，而标化考试绝对算得上是内卷重灾区。在疫情爆发的这两年，许多美国大学对标化的要求从“必须提交”改成“test-optional可选”或是“tes...
Concentration Calculations Step by step Concentration calculations involve bringing together the skills and knowledge you have acquired previously and applying them to problem solving You should be...
Concentrations of Solutions Standard solutions Chemists routinely prepare solutions needed for analysis, whose concentrations are known precisely These solutions are termed standard solutions They ...
Real Gas Behaviour The ideal gas equation does not fit all measurements and observations taken at all conditions with real gases The relationship between pressure, volume and temperature shows sign...
Gas Law Relationships Gases in a container exert a pressure as the gas molecules are constantly colliding with the walls of the container Gas particles exert a pressure by constantly colliding with...
Ideal Gas Equation Kinetic theory of gases The kinetic theory of gases states that molecules in gases are constantly moving The theory makes the following assumptions: The gas molecules are moving ...
Avogadro's Law Volumes of gases In 1811 the Italian scientist Amedeo Avogadro developed a theory about the volume of gases Avogadro’s law (also called Avogadro’s hypothesis) enables the mole ratio ...
Reaction Yields Percentage yield In a lot of reactions, not all reactants react to form products which can be due to several factors: Other reactions take place simultaneously The reaction does not...
Reacting Masses & Limiting Reactants The number of moles of a substance can be found by using the following equation: It is important to be clear about the type of particle you are referring to...
