Table of Contents Introduction 2 Analytical Method (Heuristic usability) 2 Heuristic Usability Principals 3 How to conduct heuristic evaluation? 5 Advantages 5 Disadvantages 6 Empirical Method (Usability Testing) 7 What is Usability Testing? 7 How to conduct a usability testing? 7 Advantages of Usability Testing 8 Disadvantages of Usability Testing 9 Conclusion 10 Task 2 11 Introduction 11 Description of the problem 11 Description of the difficulties 11 Conclusion:
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Chemical Formula Principles Chemical Formula is a system of chemical notation that was invented in 181 by John Jakob Berzelius. The system is based on the law of definite proportions”‚ states that all samples of a given chemical compound have the same elemental composition. It is also a way of expressing information about the proportions of atoms that constitute a particular chemical compound‚ using a single line of chemical element symbols‚ numbers‚ and sometimes also other symbols‚ such as
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Chemical Bonds Chemical Bond: is the force that holds atoms together in a compound. They form because they lower the potential energy of the charged particles that compose atoms. Chemical bonds can be broadly classified into two types: Ionic and Covalent. Ionic: metal & nonmetal Metals have a tendency to lose electrons and nonmetals have a tendency to gain them. The metal atom becomes a cation and a nonmetal becomes an anion. The oppositely charged ions attract one another and form an ionic
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What is the empirical formula of a compound that contains 75% Ag and 25% Cl by mass? AGCL Calculate the approximate number of molecules in a drop of water with a mass of 0.10 g. 3 x 1021 molecules What is the percentage composition of CaSO4? 29.44% Ca‚ 23.55% S‚ 47.01% O What mass of calcium bromide is needed to prepare 150.0 mL of a 3.50 M solution? (Assume that the molecular weight of CaBr2 is 200.618 g/mol) 105 g Nitrous oxide (N2O)‚ or laughing gas‚ is commonly used as an anesthetic
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essential that the structure is derived. Firstly it is important to determine the percentage composition of elements to work out the empirical formula. The empirical formula was found to be C10H12O and the mass of the unknown was 148.09 m/z which when calculating the molecular weight of the empirical formula it did equal 148.09 g mol -1. This means that the empirical formula is also the molecular formula. As 12.01x10 carbons +1.008x12 hydrogens + 16= 148.09 09 g mol -1. From this knowledge the unknown
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LEARNING TASK NO. 4B Composition Stoichiometry Problems Mole Relationship from Chemical Formulas: a) Determine the number of moles of chloride ions in 2.53 mol ZnCl2. b) Calculate the number of moles of each element in 1.25 mol glucose (C6H12O6). c) How many molecules of oxygen atoms are present in 5.00 mol diphosphorus pentoxide? d) Calculate the number of moles of hydrogen atoms in 11.5 mol water. e) A sample of ethanol (C2H5OH) has a mass of 45.6 g.How many carbon atoms does the sample
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1) Empirical study-a study that uses tangible observations. The data collected comes from physical means that are concrete and use the senses to gather data. (McMillian‚ 2016‚ p.7) Example: Empirical studies can be quantitative or qualitative; in research involving retention efforts they will be empirical studies conducted to gather data. 2) Theory- is an educated assumption that explains how‚ what we as researchers examine relate to each other. It creates meaning from the information gathered. McMillian
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Assignment 5 Sheet Harbour Chemicals Sheet Harbour Chemicals (SHC) manufactures chemicals used in the paint industry. The process involves three departments. Chemical A‚ which is purchased for $3 per liter‚ is processed through Department 1 in batches of 100 liters. Each batch of chemicals processed through Department A produces 70 liters of chemical B and 30 liters of chemical C. Chemical B is sold for $10 per liter. Chemical C is used in Department 2 to produce chemicals D‚ E‚ and F. Department 2
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* Chemical Formulas and Reactions . . . Midterm Objectives: * To balance chemical equations. * To interpret chemical reactions. * To understand equilibrium reactions and the factors that can affect them. * Molecular Mass / Formula Mass * Is the sum of the atomic masses of all the atoms present in one molecule of that compound. Example: the molecular mass of sodium bromide‚ NaBr‚ is 103‚ which represents the sum of the atomic mass of sodium (23) plus that of bromide (80)
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Chapter 1 Chemical Reactions and Equations Q.1. Why should magnesium ribbon be cleaned before burning in air ? Ans: Magnesium ribbon is a very reactive metal. When stored it reacts with oxygen to form a layer of magnesium oxide on its surface. This layer of magnesium oxide being a stable compound prevents further reaction of magnesium with oxygen. The magnesium is cleaned before burning in air to remove this layer so that the metal can be exposed to air properly. Q.2. Write the balanced
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