NSS Chemistry Part 3 Metals HKCEE Past Paper Questions – Structural Questions 1. HKCEE 1995 Q1 Rubidium (Rb) and potassium belong to the same group in the Periodic Table. The relative atomic mass of rubidium is larger then that of potassium. (a) Explain whether rubidium is more reactive than potassium. (b) Write a chemical equation for the reaction between rubidium and water. (State symbols should be given.) (c) Suggest how rubidium can be stored safely in the laboratory.
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Surname Centre No. Initial(s) Paper Reference 4 3 3 5 Candidate No. 2 H Signature Paper Reference(s) 4335/2H Examiner’s use only London Examinations IGCSE Team Leader’s use only Chemistry Paper 2H Higher Tier Wednesday 17 June 2009 – Morning Time: 2 hours Materials required for examination Nil Items included with question papers Nil Question Leave Number Blank 1 2 3 4 5 6 7 8 9 Instructions to Candidates In the boxes above‚ write your centre number‚ candidate number‚ your surname
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rusting of iron. An example of this is adding NaCl (salt) to the water. When salt is dissolved in water‚ it is separated into Na+ and Cl- ions. These ions attach themselves separately to the charged parts of the water molecule (H20). When Na and Cl ions are present in water‚ there is an increase in the ability of the water to carry electrons as there are more ions in the water‚ therefore the iron will rust faster. There are also many factors that will inhibit the rusting of iron. Examples of this
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and does not produce a photon. This is occurs often when heavy halides are in the solution because they increase vibrational relaxation
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HOMEWORK EXAM 3: Chapter 19: The half life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later? Answer 0.166 0.125 0.062 here 0.015 Which relation is not correct? Answer 11p = 11H = proton 0-1e = 0-1β = electron here +10e = +10β= positron 10n = neutron As a result of beta decay‚ the product nucleus is Answer one atomic number lower than the original element. two atomic number
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polyatomic ions. Polyatomic ions behave as a unit. If you need more than one of them‚ enclose them in parentheses when you write formulas. You need to know their names‚ formulas‚ and charges. If you learn the nine that follow‚ you can get many others from applying two simple patterns. Name of polyatomic ion | Formula and charge | Ammonium ion | NH4+ | Acetate ion | C2H3O2- | Cyanide ion | CN- | Hydroxide ion | OH- | Nitrate ion | NO3- | Chlorate ion | ClO3- | Sulfate ion | SO42- |
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rate of flow of charge. What is Electrolyte? The electrolyte in a cell is a chemical medium that allows the flow of electrical charge between the cathode and anode.” . The electrolyte is usually a solution of water or other solvents in which the ions are dissolved.
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Name: __________________________________ ( ) Class: 4Q HWA CHONG INSTITUTION PRELIMINARY EXAMINATION 2010 CHEMISTRY 5072 Paper 1 Time: 1 hour INSTRUCTIONS TO CANDIDATES Do not turn the pages over until you are told to do so. Write your name and index number on the answer sheet in the spaces provided. There are forty questions on this paper. Attempt all questions. For each question‚ there are four possible answers labelled A‚ B‚ C and D. Choose the one you consider correct and
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AustStab Technical Note No.1 May 2002 Lime stabilisation practice 1 Introduction Lime stabilisation of materials is one of the oldest forms of stabilisation and sometimes the least understood. The stabilisation of clay subgrades using quicklime has a long and successful history in many urban and rural regions of Australia‚ and is cost effective and a necessary requirement for Municipalities and State Road Authorities seeking long-life roads to minimise future maintenance costs.
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of particle theory Atom: The smallest particle that cannot be divided by any physical or chemical means Molecule: Two or more atoms (the same or different) that are chemically bonded together Lattice: 3D array of oppositely charged particles (ions) held together by an electrostatic attraction Element: Consists of only one type of atom Compound: Composed for two or more elements that are chemically bonded together. Contains a fixed number of atoms of each component element. Pure Substance:
Free Atom Chemical bond Oxygen