WJEC CBAC AS/A LEVEL GCE in Chemistry REVISION AID UNIT 1 AS UNIT CH1 – Controlling and Using Chemical Changes (in order to make things‚ produce energy and solve environmental problems) Preamble This unit begins with some important fundamental ideas about atoms and the use of the mole concept in calculations. Three key principles governing chemical change are then studied‚ viz. the position of equilibrium between reactants and products‚ the energy changes associated with a
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for gold mining are South Africa and a lot of US productions come from South Dakota and Nevada. The symbol for gold is Au for its Latin name Aurum rather than the English G. The atomic number is seventy nine but Gold has isotopes which are stable and radioactive. A stable isotope is 197 Au and there are 36 radioisotopes with 195 Au. Gold is a dense‚ shiny‚ ductile metal the most characteristic feature is that gold is a metallic yellow color which gives it the gold color. Because of the the color
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a very high speed particle with no charge. False Ionization energy is required to add an electron to a neutral atom. False The nuclear product of radioactive decay is called the daughter nuclide. True A gamma ray emission results in the release of energy without any apparent change in mass or nuclear charge. True The half-lives of unstable isotopes vary from milliseconds to billions of years. True The combining of atoms is known as nuclear fusion. True Multiple choice (27points) The man responsible
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Copper is the 29th element in the periodic table‚ located more specifically at group 11‚ period 4. Because of its chemical and physical attributes‚ it is a transition metal‚ which denotes high boiling and melting points. Both a conductor of heat and electricity‚ Copper is ductile and malleable. Its symbol “Cu” derives from the Latin cuprum. Copper is also valued for its two-for-one practicality: it is a vital nutrient that has antibacterial properties. Aside from what many people generally know about
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equal parts sodium (NA) and chlorine (Cl)=NaCl) 3. ATOMIC NUMBER= # of protons MASS NUMBER= pro + neutrons 4. An Isotope is an element with the same number of protons and electrons but a different number of neutrons. RADIOACTIVE ISOTOPES the nucleus decays spontaneously giving off particles and energy. Useful for tracing cells in the body when they pick up this radioactive isotope. 5. The farther an electron is from the nucleus‚ the greater its energy. Numbers of electrons in the outermost shell
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IS NUCLEAR ENERGY A SOLUTION TO THE ENERGY CRISIS? Contents * Abstract * Introduction * Report * Conclusion * Bibliography * Appendix Abstract Nuclear energy could be the future of energy and potentially solve the energy crisis problem. Nuclear energy is a sustainable energy source and it can provide millions of times the amount of energy output from a fixed mass of fuel than any other energy source‚ such as fossil fuel‚ for the same mass of fuel.
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Physics Final Exam revision b 11/7/14 Directions: It is important that you provide answers in your own words. Please focus only on information from the text/eBook to create your own solutions. Please do not use direct information from an outside source (especially copying and pasting from an “answer” website). Use of direct information from an outside source is against school policy. All answers will be checked for plagiarism. Instances of plagiarism can result in probation or possible
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number - from hydrogen (1) to whatever is the highest one currently known (>105). It is arranged so that similiar members fall in a list such as Chlorine Bromine etc.. The average atomic weight is usually shown with each element‚ but due to isotopes (caused buy nuclear varations) the weight is the normal average atomic weight. The table illustrates the similiarity of various elements such as metals‚ noble gases‚ rare earths‚ halides‚ etc. in that they fall into series within the table. The
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Earth’s crust. The percentages of the halogens in the igneous rocks of Earth’s crust are 0.06 fluorine‚ 0.031 chlorine‚ 0.00016 bromine‚ and 0.00003 iodine. Astatine and element 117 do not occur in nature‚ because they consist of only short-lived radioactive isotopes. The halogen elements show great resemblances to one another in their general chemical behaviour and in the properties of their compounds with other elements. There is‚ however‚ a progressive change in properties from fluorine through chlorine
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-270.98°C becomes a superfluid. Helium becomes solid at -272.2°C at pressures above 26 atmospheres‚ helium boils at -268.9°C and has a density of 0.1664 g/litre at 20°C and one atmosphere. The stable isotopes of helium are a rare form of helium-3 and the most common form of helium-4. Isotopes from helium-5 to helium-10 are unstable and rapidly decay‚ these are only known from certain nuclear reactions and experiments with particle accelerators. Because helium’s’ electron shell is always full
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