equation. 14What are oxidation and reduction reaction? 15. Why do gold and platinum not corrode in moist air? Short Answers 1. Write balanced chemical equation for. a. Zinc metal reacts with aqueous solution of hydrochloric acid to form zinc chloride solution and hydrogen gas. b. Solid mercury (II) oxide is heated‚ liquid mercury and oxygen gas is produced. c. Aqueous solution of sulphuric acid and sodium hydroxide react to form aqueous sodium sulphate and water.
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the balanced chemical equation for the decomposition of water to its elements. 2H2O(l) 2H2(g) + O2(g) 2. (a) Assign oxidation states to the hydrogen and oxygen atoms in each substance in the above chemical equation. The oxidation state of H2(g) and O2(g) is zero‚ because they are in their normal state. (b) Based on the changes in oxidation states for each atom‚ identify the atom that is oxidized and the atom that is reduced in the decomposition of water. Hydrogen atom is reduced
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produces corresponding calcium salts with liberation of CO2: CaCO3 + 2HNO3 Ca(NO3)2 + H2O + CO2(g) In this experiment‚ the mineral acid is added in excess to the calcium carbonate and the excess titrated against standard sodium hydroxide. This kind of titration is termed back titration. In this procedure‚ the analyte is consumed using excess titrant and the end
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example‚ the sodium cation is indicated as Na+ and not Na1+. An alternative (and acceptable) way of showing a molecule/atom with multiple charges is by drawing out the signs multiple times; this is often seen with transition metals. Chemists sometimes circle the sign; this is merely ornamental and does not alter the chemical meaning. All three representations of Fe2+ shown in the figure are‚ thus‚ equivalent. Mixed Roman numerals and charge notatios for the uranyl ion. The oxidation state of the
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presence of weak agents. Although regular re-standardization was essential for Iodine solution due to its lack of stability‚ it was still suitable for titrations due to its advantage of having sensitive and reversible indicator [5]. Reduction-oxidation titrations involving iodine were classified mainly into two; Iodimetry and Iodometry. Iodimetry was a direct method involving only one reaction between the titrant and the analyte [6]. ( )( ( ) )( ( ( ) ) ) In Reaction
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for food? And how is the use of food preservatives affects this all? What is Food Preservatives? Preservation usually involves preventing the growth of bacteria‚ fungi and other micro-organisms‚ as well as retarding the oxidation of fats which cause rancidity. Food preservation can also include processes which inhibit visual deterioration‚ such as the enzymatic browning reaction in apples after they are cut‚ which can occur during food preparation. Many processes designed
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Chemical equations are the symbolic representations of chemical reactions that are made up of reactants and products. It is made up of the chemical formulas of the reactants and the chemical formula of the products. The reactants are the substances or chemicals that takes part in during a reaction and the products are the chemicals are the substances that result from the chemical reaction. Reactants are on the left side of the chemical equation and the products are on the right side of the chemical
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90696 906960 For Supervisor’s use only 3 Level 3 Chemistry‚ 2008 90696 Describe oxidation-reduction processes Credits: Three 9.30 am Friday 28 November 2008 Check that the National Student Number (NSN) on your admission slip is the same as the number at the top of this page. You should answer ALL the questions in this booklet. A periodic table is provided on the Resource Sheet L3–CHEMR. If you need more space for any answer‚ use the page(s) provided at the back of this booklet and clearly
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Topic 11a – Group 7‚ the Halogens Revision Notes 1) Trends in physical properties of the elements • At room temperature‚ Cl2 is a pale green gas‚ Br2 is a brown liquid‚ I2 is a blue-black solid. • In Group 7‚ boiling point increases down the group because the molecules have more electrons and‚ therefore‚ stronger van der Waal’s forces which require more energy to overcome them • Electronegativity is the ability of an atom to attract the electrons in a covalent bond • Down
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Writing Half Reaction and Net Ionic Equation Going back to our first concept or topic‚ we’ve learn how to identify the Oxidizing and Reducing agent and the Oxidation as well as the Reduction. In this part of the Redox reaction or in this step‚ it is very important that you already know the Oxidizing and Reducing agent for us to find the half reaction. In this step or part‚ we will also learn how to balance using the addition of electrons in both sides if necessary. After this step we can now write
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