Exam #1 Study Notes

Exam #1 Study Notes - Chemistry Exam#1 Study Notes Unit 1.1...

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Chemistry Exam #1 Study Notes Unit 1.1 Notes Chemistry is the study of matter and the changes it undergoes Matter is anything that has mass and occupies space and is made up of almost infinitely small building blacks called atoms Atoms combine together to form molecules Mixtures can be homogenous (uniform throughout) or heterogeneous (looks different) If molecules contain one kind of atom, its an element, if it contains two or more different atoms, it is a compound Monoatomic molecule (one); Diatomic molecule (two); Triatomic Molecule (three); Tetratomic molecule (four)…. Unit 1.2 Notes Law of conservation of mass- in a chemical reaction, mass is conserved Modern view of the atom: positively charged nucleus surrounded by negatively charged electrons Protons and Neutrons make up nearly all of the mass of an atom, but they occupy only a very small percentage of its volume Mass= number of protons plus number of neutrons in the nucleus (top) Atomic Number= Number of Protons in the nucleus (bottom) Elements are arranged in order of increasing atomic number (# of protons) Elements with similar chemical properties fall in the same columns (groups, with same number of valence electrons) The further away from the nucleus, the higher the energy levels Octet Rule: atoms tend to gain, lose or share electrons until they are surrounded by eight valence electrons to be more stable Ionic Bond, give electrons away Covalent Bond, share electrons Unit 1.3 Notes Electromagnet Radiation (EM Radiation) is a form of energy that is described by a wave Wavelength: distance between peaks Frequency (v): number of peaks passing a fixed point in one second The shorter the wavelength, the higher the energy The higher the frequency, the higher the energy Energy is not a continuum Wavelengths are often measured in nanometers (nm) Absorption of radiation: o Use a light source and measure the intensity of the light o Photos- particles of light o Measure the intensity of the liht (how bright it is( using a detector (your eyes can even be a detector) o Detector produces a signal, telling the brain or computer how intense the light is o Put between the light source and the detector a sample (anything that absorbs radiation and weakens the intensity that reaches the detector). The thicker the
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sample the more intensity if absorbed and the darker the sample the more absorbency of light. o Lambert-Beer’s Law: A = Elc A= absorbency E= Extinction coefficient (number that makes a unit) l= path length (of sample) c= concentration (of sample) Unit 2.1 Notes: When you have two forms of the same element, they are called allotropes (eg- O3 and O2) Photochemical smog is the tropospheric zone. Ozone in the troposphere is a pollutant, but ozone in the stratosphere is needed to
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Exam #1 Study Notes - Chemistry Exam#1 Study Notes Unit 1.1...

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