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目前显示的是 六月, 2020的博文

学习日记(foundation-chemistry)

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 c hapter5:Atomic Structure and the Periodic Table Different Theories of the Atom Classical View of the Universe Since the time of the ancient Greeks, the stuff of the physical universe has been classified as either matter or energy. -Matter:所有东西都有重量和体积 -Energy:不可分解的分子,但可以通过waves里面流动 The Nature of Light—Its Wave Nature -Light 是从electromagnetic radiation产生的 -Electromagnetic radiation 是通过waves产生的; traveling at a velocity “c” -Electromagnetic radiation 通过waves来移动然后通过pond的surface -wave有4个点,来确认他们的特点 。wave speed, 。height (amplitude), 。length, 。number of wave peaks that pass in a given time. -所有的electromagnetic waves会移动穿过空间在同样的,固定的速度 。3.00 x 10^8 meters per second in a vacuum = speedof light, c. Characterizing Waves -amplitude=wave的高度 。是从node到crest的距离 。是来测量intense of the light -amplitude越大,light越亮 -wavelength(λ)=测量wave cover的距离 。是2个crest之间的距离 。是个完整的cycle2π 。通常用nanometers来测量,1 nm = 1 x 10-9 m -frequency(ν)=waves通过一段时间(period)的数量 。The number of waves = number of cycles. 。Units are hertz (Hz), o

学习日记(foundation-chemistry)

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  chapter 4:Chemical Composition -所有物质都是化学的,或者物理组合成物质。 Experiencing Atoms -91个elements 可以在大自然中找到,多过20中是人造的 -所有element是从不同的atom做出来的 -所有的atom有eletron(-ve),proton(+ve)和neutron(neutral) -proton和neutron被packed在小小的中心叫nucleus,然后它的外围是有electron聚集的 -所有的atoms被认为是球体 Sizes of Atoms -Volume of atom 。被认为是球体,然后也被叫成atomic radius 。 atomic volume增加当atomic number of  atom increase -Mass of atom 。Atomic mass unit (amu)(1 amu = 1.6605 x 10^-24) *大部分发现的element是在大自然的作为mixture of isotopes *所有的isotopes在一个atom是存在specific ratio 被称为abundance *Atomic mass of an atom Y= ΣX1 M isotopeY1 + X2 M isotopeY2+…. X1, X2 are abundance of isotope Y M1, M2 are relative mass unit of isotope Y 。Molar mass of atom(mass of 1 mol of atom (g/mol or gmol-1) 。Formula mass (mass of 1 mol of molecule/formula (g/mol)) Counting Atoms by Moles -mole=物质的数量,包含尽可能多的objects(microspecies such as atoms, molecules, ions etc.) as the number of atoms in exactly 12 g 12C -The number of atoms use is 6.022 x 10^23(Avogadro’s number.) mole concept Rela