Scribd Extrascore Sample Questions - Answers Q.1: What are the µlaws of chemical combination¶? Ans: There are two important laws of chemical combination established by Lavoisier‚are as follows: (i) Law of Conservation of Mass The law of conservation of mass states that mass can neither be created nor destroyedin a chemical reaction.(ii) Law of Constant Proportions The Law of Constant Proportions which is also known as the Law of DefiniteProportions‚ was established by Proust
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atom are removed and attached to another atom‚ resulting in positive and negative ions which attract each other. Other types of bonds include metallic bonds and hydrogen bonding. The attractive forces between molecules in a liquid can be characterized as van der Waals bonds. What is an Ionic Bond? An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed due to the attraction between an atom that has lost one
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1 OCTOBER 5 2013 QUALITATIVE TESTS FOR SOME CATIONS II I. Introduction Qualitative analysis schemes are often based on selective precipitation of different cations. By carefully selecting reagents and conditions for reactions‚ groups of ions can be separated on the basis of their reactivity and the solubility of their salts. This enables the experimenter to use simple techniques with standard laboratory equipment‚ as well as to learn some descriptive chemistry. Cations are Alkali and Alkaline
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Gerona‚ Evelyn Chemical Reactions Experiment No. 7 Date Performed: Feb. 17‚ 2014 Date Submitted: Feb. 24‚ 2014 Mrs. Vitancol I. Theoretical Framework A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically‚ chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms‚ with no change to the nuclei (no change to the elements present)‚ and can often
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redox of Cu2+ and Zn‚ and precipitation of Zn(OH)2‚ leading to an overall reaction of Cu(OH)2(s) + Zn(s) ⇌ Zn(OH)2(s) + Cu(s). When 6.0 M HNO3 was added to the fourth test tube‚ the precipitate disappeared. The H+ ions from the complete dissociation of HNO3 neutralize the OH- ions. This results to the shifting of the system to the right. The addition of 6.0 M NH3 in the fifth test tube caused the formation of the deep blue [Cu(NH3)4]2+ complex. The new equilibrium was established from the dissociation
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of the three dyes? a. Red No. 40‚ Blue No. 1‚ Yellow No. 5 contain carbon rings and NaSO3. Additionally‚ Red No. 40 and Yellow No. 5 are very similar‚ as they both contain one nitrogen double bond‚ a hydroxyl group‚ and no ions. Blue No.1 contains nitrogen and chlorine ions and N(C2H5)CH2. 2. In the Introductory Activity‚ the developing solvents were 2% sodium chloride aqueous solution and 2% isopropyl alcohol aqueous solution. Draw separate molecular diagrams of how sodium chloride and isopropyl
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ELECTRONEGATIVITY This page explains what electronegativity is‚ and how and why it varies around the Periodic Table. It looks at the way that electronegativity differences affect bond type and explains what is meant by polar bonds and polar molecules. If you are interested in electronegativity in an organic chemistry context‚ you will find a link at the bottom of this page. What is electronegativity Definition Electronegativity is a measure of the tendency of an atom to attract a bonding pair
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Determine the cation and anion in an unknown solution All salt solutions have both positive (Cations) and negative (Anions) ions dissolved in it. In this experiment you will observe chemical reactions to determine the presence of specific anions and cations. Compare your observations with the reactions of the known solutions and the unknown solution to determine the ions present in the unknown solution. You will use a flame test for the cations‚ Na+‚ K+‚ and Ca+2 Perform qualitative tests for
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the urine and neutralizes the acid compounds of the body such as phosphates‚ urea and ammonia. It is‚ therefore‚ highly beneficial in the treatment of acidosis and other diseases associated with too much acid in the system. The presence of oxalate ions and oxalic acid content in tomatoes is also a cause of kidney stones. Several researches have proven that the
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Microscopes were invented in the 1600s. Robert Hooke first looked at a thin slice of cork in 1665; he saw "a lot of little boxes." These little boxes first reminded of the little rooms monks lived in‚ so he called them cells. Hooke observed the same pattern in the stems and roots of carrots and other plants. What Hooke still did not know‚ however‚ was that cells are the basic units of living things. Ten years later‚ the Dutch scientist Anton van Leeuwenhoek focused a microscope on what seemed to
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