emission line results. Each element has a unique emission spectrum. A metal can be identified if it has a strong emission line in the visible region of the electromagnetic spectrum. Thus when a compound such as NaCl is vaporized in a flame‚ ion pairs are converted to gaseous atoms. Na(g) atoms are excited to high energies‚ and 589nm (yellow) light is emitted as the excited atoms revert to their ground state electronic configurations. Therefore‚ the cation in the unknown substances can
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that this paper will answer. How do ionic compounds form? Ionic compounds are formed by positive and negative ions. An ionic bond means that there are valence electrons being shared between the two molecules. This can cause the molecule to become negative or positively charged. An ionic compound is formed by the complete transfer of electrons from a metal to a nonmetal and the resulting ions have achieved an octet. The protons do not change. Metal atoms in groups one through three lose electrons to
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PAHANG TRIAL 2009 EXAMINATION CHEMISTRY PAPER 2 MARKING SCHEMES SECTION A - Structural Questions: Question 1. (a) (i) The presence of isotopes 1M (ii) Let the abundance of 63X be a %. The % abundance of 65X. = ( 100 – a ) 1M Relative atomic mass = ( 62.93 x a) + ( 64.93 x ( 100 -a) ) 1M
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to determine unknown ions present in chemical samples by observing and analyzing results from various reactions of the sample with chemicals. Qualitative analysis is done through a series of steps. It is usually divided into two parts‚ namely: the preliminary and confirmatory tests. Preliminary tests are done to eliminate ion choices‚ while confirmatory tests are done to confirm the actual ions present in the sample. Qualitative analysis was done to identify the ions present in a given unknown
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GaView prior to lab 1. How will you prepare a .02% (m/v) NBS solution? Calculations should be in your notebook before arriving to lab. 2. Provide the structure of vitamin C in its reduced form (ascorbic acid)‚ its ionized form (ascorbate ion- this is at equilibrium with reduced form when dissolved)‚ and its oxidized form (dehydroascorbate). 3. Why do you think that the indicator solution contains acetic acid? How might its absence affect the titration? 4. How much vitamin C has
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Name: |Date:| Exp 1: Observations of Chemical Changes|Lab Section: | Data Tables: Part 1: |Chemicals|Well No.|Observations of the Reaction| A.|NaHCO3 + HCl| H12|White and bubbled slightly and settled down to smaller smaller bubbles| B.|HCl + BTB| H11|Golden yellow; looked darker under the black paper| C.|NH3 + BTB|H10 |Dark blue| D.|HCl + blue dye| H9|Greenish color| E.|Blue dye + NaOCl| H8|Blue and lighter than NH3+BTB solution color| | with the 1 drop of HCl| H8|Turned blue green
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Sodium Bicarbonate + Hydrochloric Acid 2. Hydrochloric Acid + Bromothymol blue 3. Ammonia + 1 drop Bromothymol blue 4. Hydrochloric acid + blue dye 5. Blue dye + Sodium Hypochlorite. Observe & add 1 drop of hydrochloric acid. 6. Potassium iodide + Lead Nitrate. A precipitate should form. 7. Sodium hydroxide + phenolphthalein. a. Phenolphthalein is an acid-base indicator. 8. Hydrochloric acid + phenolphthalein. a. What color would be expected when combining phenolphthalein with an acid
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Kinetics Kinetics 6.1 Rates of reaction 6.2 Collision theory 6 16.1 Rate Expression (AHL) 16.2 Reaction mechanism (AHL) 16.3 Activation energy (AHL) 6.1 Rates of reaction 6.1.1 Define the term rate of reaction. 6.1.2 Describe suitable experimental procedures for measuring rates of reactions. 6.1.3 Analyse data from rate experiments. © IBO 2007 Figure 601 An explosion is a quick reaction D ifferent chemical reactions occur at different rates (i.e. speeds)
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Data Tables: Part 1: Chemicals Well No. Observations of the Reaction A. NaHCO3 + HCl A1 Bubbles immediately formed and started popping (not rapidly). This could be seen more easily with the black paper underneath the well plate B. HCl + BTB C1 Once I added the Bromothymol Blue indicator‚ it turned an orange-like color C. NH3 + BTB E1 The reaction turned dark blue. When Bromothymol Blue reacts with an acid‚ it turned orange‚ and when it reacts with a base‚ the end result is blue. D. HCl
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the dead bodies. I am going to explain what Ions are including Cations and Anions because it is the background information needed to carry out this investigation. An ion is an atom or molecule which the total number of electrons isn’t equal to the total number of protons giving the atom a positive or negative electrical charge. When an atom is attracted to another atom because it has an unequal number of electrons and protons‚ the atom is called an Ion. If the atom has more electrons than protons
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