C2.1.1 Structure and bonding a) Compounds are substances in which atoms of two or more elements are chemically combined. b) Chemical bonding involves either transferring or sharing electrons in the highest occupied energy levels (shells) of atoms in order to achieve the electronic structure of a noble gas. c) When atoms form chemical bonds by transferring electrons‚ they form ions. Atoms that lose electrons become positively charged ions. Atoms that gain electrons become negatively charged
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Electrolysis a) Electrolysis is the decomposition of a substance to give simpler substances. The substance being electrolysed has to be an ionic compound. b) The substance being decomposed is called the electrolyte. c) In electrolysis the electric current enters and leaves the electrolyte by conducting rods called electrodes. The positive electrode is called the anode and the negative electrode is called the cathode. d) For electrolysis to occur the electrolyte must be in liquid form so that
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Ch1: Atomic structure Discovering the electron - When electricity flows in an aqueous solution of ionic compounds‚ the metal ions appears at the negative electrode (cathode). - The metal exists in the solution as positively charged particles known as ions. - A 1+ ion plus one unit of electricity gives one metal atom. - Low pressures gases conduct electricity very well. - The glass of containing vessel opposite the cathode (negatives electrode) glowed when the applied potential difference
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Science Revision Notes Chemistry Atoms are the smallest particle of a particular element. Molecules are particles that contain 2 or more atoms joined together by chemical bonds. Elements are substances that are made up of only one type of atom. Compounds are substances form when two or more elements are joined chemically. Metals are solid at room temperature‚ with the exception of mercury. Metals are good conductors of electricity and heat. Metals can usually be melted at high temperatures. Non-metals
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CHEMISTRY REVISION GUIDE for IGCSE Coordinated Science This revision guide is designed to help you study for the chemistry part of the IGCSE Coordinated Science course. The guide contains everything that the syllabus says you need you need to know‚ and nothing extra. The material that is only covered in the supplementary part of the course (which can be ignored by core candidates) is highlighted in dashed boxes: Some very useful websites to help you further your understanding include: •http://www
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5.3. Suppose that you enter into a 6-month forward contract on a non-dividend-paying stock when the stock price is $30 and the risk-free interest rate (with continuous compounding) is 12% per annum. What is the forward price? Solution: = = 31.86 5.9. A 1-year long forward contract on a non-dividend-paying stock is entered into when the stock price is $40 and the risk-free rate of interest is 10% per annum with continuous compounding. (a) What are the forward price and the initial value of the forward
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Surname Centre No. Candidate No. Paper Reference(s) Initial(s) Paper Reference Signature 6 6 6 3 6663/01 0 1 Examiner’s use only Edexcel GCE Core Mathematics C1 Advanced Subsidiary Monday 10 January 2011 – Morning Time: 1 hour 30 minutes Team Leader’s use only Question Leave Number Blank 1 2 3 4 Materials required for examination Mathematical Formulae (Pink) Items included with question papers Nil 5 6 7 8 9 Calculators may NOT be used in this examination
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Chapter 2 SSD Architecture and PCI Express Interface K. Eshghi and R. Micheloni Abstract Flash-memory-based solid-state disks (SSDs) provide faster random access and data transfer rates than electromechanical drives and today can often serve as rotating-disk replacements‚ but the host interface to SSDs remains a performance bottleneck. PCI Express (PCIe)-based SSDs together with an emerging standard called NVMe (Non-Volatile Memory express) promises to solve the interface bottleneck. This chapter
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CHAPTER 4 REVISION 1. How many moles of silver atoms are in 0.780 grams of silver? a) 0.78 moles b) 0.00723 moles c) 84.2 moles d) 0.522 moles 2. What is the molar mass of Mg(BrO4)2? a) 312 g mol-1 b) 232 g mol-1 c) 168.2 g mol-1 d) 477 g mol-1 3. What mass of the compound FeWO4 contains 50.0 grams of tungsten (atomic symbol W‚ atomic number = 74)? a) 30.0 g FeWO4 b) 304 g FeWO4 c) 82.6 g FeWO4 d) 188 g FeWO4 d) FeSO4 4. A compound contains 20.2%
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C1 ALIBABA.COM 1. Creating other successful portal in the future will be hard given that the lock-in effect makes the task difficult. Alibaba.com as an early entrant into the B2B portal market in China has built a strong advantage over its competitors; anyone who would want to challenge them will face some barriers to enter the market because as a starter‚ people will show preference for Alibaba.com‚ because of the experience‚ some people also develop loyalty or simply because they know the company
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