...Version: 10/08/2012 General Certificate of Secondary Education Additional Science 4408 / Chemistry 4402 CH2HP Unit Chemistry 2 Mark Scheme 2012 examination – June series Mark schemes are prepared by the Principal Examiner and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation meeting attended by all examiners and is the scheme which was used by them in this examination. The standardisation meeting ensures that the mark scheme covers the students’ responses to questions and that every examiner understands and applies it in the same correct way. As preparation for the standardisation meeting each examiner analyses a number of students’ scripts: alternative answers not already covered by the mark scheme are discussed at the meeting and legislated for. If, after this meeting, examiners encounter unusual answers which have not been discussed at the meeting they are required to refer these to the Principal Examiner. It must be stressed that a mark scheme is a working document, in many cases further developed and expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark schemes on the basis of one year’s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper. Further copies of this Mark Scheme are available to download from the...
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...materials Lijani van Wyk de Vries Matter and materials Effects of intermolecular forces on physical properties A. Effects of intermolecular forces on evaporation: ------------------------------------------------- Investigative Question What is the relation between intermolecular forces and evaporation, and what are the effects thereof? ------------------------------------------------- Hypothesis I think water will have the highest vapour pressure, and acetone the lowest, and thus that the substance with the strongest intermolecular forces will have the lowest vapour pressure. ------------------------------------------------- Variables INDEPENDENT: substance DEPENDANT: evaporation CONSTANT: circumstances, amount used (number of drops) ------------------------------------------------- Record Data and analyze data SUBSTANCE | TIME IN SECONDS | Ethanol | 83 | Water | No change after one hour (3600 sec) | Acetone | 20 | Methylated Spirits | 90 | Water (H2O) took the longest to evaporate (having made no difference after more than an hour) – this is because water has strong hydrogen bonds. . The methylated spirits (mainly CH3CH2OH and CH3OH) and ethanol (CH3CH2OH) evaporated completely within just over a minute – due to the hydrogen bonds, which are weaker than that of water. Acetone (CH3COCH3) evaporated almost immediately (20 sec) –because acetone has weak dipole-dipole forces. As the substances evaporated the drop expanded and then decreased...
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...effect of chemical structures of different organic compounds on two physical properties: their melting point and their boiling point. Melting point of compounds can be affected by intermolecular forces of attraction, geometric isomerism and purity. Boiling point of compounds can also be affected by intermolecular forces of attraction and by branching. The main purpose of this experiment is to (1)determine the effect of intermolecular forces of attraction and geometric isomerism on melting point of compounds, (2)determine the effect of purity on the melting point range of organic compounds and (3)determine the effect of intermolecular forces of attraction and branching on the boiling point of organic compounds. We can obtain wrong data as we encountered different errors while performing this experiment. As we go along to this laboratory report, we will able to know the effects of the different factors in melting point and boiling point of the compound and why the used compound arranged on that decreasing or increasing melting point or boiling point. Keywords: melting point, boiling point, intermolecular forces of attraction, geometric isomerism and branching[pic] INTRODUCTION Determination of melting point and boiling point of organic compound can be affected by different factors like intermolecular forces, impurity and branching that can affect the temperature of the melting point and boiling point of the compound you can achieved when you performed the...
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...AND BOILING POINT OF ORGANIC COMPOUNDS ABSTRACT One of the methods to identify an organic compound is by determining its physical properties. In this experiment, we will only looking for their melting point and boiling point on the effects of the chemical structures. Melting point is defined as the temperature at a specific pressure which the solid and liquid phases are in equilibrium with each other. The boiling point is used to characterize a new organic liquid and knowledge of the boiling point helps to compare one organic compound to another, as in identifying unknown organic compound. The purpose of this experiment is to determine the effects of: intermolecular forces of attraction and geometric isomerism in the melting point of compounds; purity on the melting point range of organic compounds; intermolecular forces of attraction and branching on the boiling point of organic compounds. To do the experiment, Thomas Hoover apparatus is used for determine the melting point and micro test for the boiling point. Salicylic acid has the highest melting point between the rest of the sample with 152.5-157.1°C range and naphthalene has melted fastest as it melted at 75.8-80.6°C for the first part of the melting point experiment. The melting point of fumaric acid is between 278-286°C which is higher than Maleic acid with 122.3-131.8°C. Meanwhile, the pure urea has 127-132.2°C melting point which is higher than impure urea with 98.5-128.5°C. Meanwhile, Propanoic acid has the highest...
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...3, the intermolecular forces that are present include LDF, dipole-dipole, and hydrogen bonding since all are part of the alcohol group and all contain an OH group. 2. The IMFs that are present in the molecular series 4 include only LDFs because they are part of the alkaline group and are hydrocarbons that contain only carbon(C) and hydrogen (H) single bonds. 3. A. The factor that is affecting IMF strength from one molecule to the next is London Dispersion Forces. B. As we go from methanol→ ethanol→1-propanol→ 1-butanol, the dispersion force increases. C.. As we see on the attached Evaporative Cooling Data chart on Appendix A1, the ∆T increases in the following order, from methanol→ethanol→ 1-propanol, and finally to 1-butanol having the highest ∆T. The strength of IMF is affected by ∆T, thus, the greater the negative ∆T is, the weaker the intermolecular force will be and the less negative ∆T will result in a stronger intermolecular force. D. If we look at the Spartan Data on Table 4 on pg. L119, we can see that the surface area of each molecule is increasing from methanol→ ethanol→ 1-propanol, and finally to 1-butanol. Increasing molecular surface area will increase dispersion forces. Finally, if we go back to Appendix A1, we see that the molar mass is increasing from methanol, to ethanol→ 1-propanol→1-butanol. When the molar mass in a molecule is increased, it leads to an increase in the number of electrons in the molecule, which increases dispersion forces. E. Hypothesis:...
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...A REVIEW OF FLUIDIC SELF ASSEMBLY Towards the fulfillment of course requirement for EE5171 Under Prof. Stephen Campbell Electrical and Computer Engineering University of Minnesota, Twin Cities By: Manan M Dedhia ID # 4279398 M.S. Graduate student Electrical and Computer Engineering University of Minnesota, Twin Cities THE INTEGRATION of microelectromechanical systems(MEMS) sensors and actuators with other classes of microcomponents—electronic, optical, and fluidic—onto a single substrate has the potential to create powerful and complex microsystems. To increase device performance and thus realize the potential of microsystems, it is now accepted that the integration must occur at the micro scale. There are two possible routes: either the micro-components are fabricated at their desired locations in a single process, or they are fabricated separately and then positioned using micro assembly techniques. Since many classes of micro components cannot be co-fabricated effectively due to materials and process incompatibilities, several research groups are developing micro assembly approaches. In the micro assembly route, different classes of micro components are fabricated in separate processes, removed from their substrates, and assembled onto a target substrate of choice. For most applications, sub micrometer positioning and methods for establishing high-quality mechanical and electrical connections to the substrate are required. As in co fabrication, small-area electrical...
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...9BH, UK Received 10 October 1994; accepted 9 December 1994 Abstract The mechanical resistance of gel systems was measured by means of a gel strength tester. Measurements were performed using a standard sample holder and probes of different geometry (conical, spherical and cylindrical). The systems tested were a K-carrageenan aqueous gel and a semisolid hydrophilic colloidal solution of hydroxypropylmethylcellulose. Blank measurements were also carried out using distilled water in order to take into account the buoyancy effect of the probe. The conical probe exerts mainly shear stresses on the gel, whereas the spherical and, to a greater extent, the cylindrical probe mainly exert compression stresses. Analysis of the shapes of the force-displacement curves has led to isolation of the shear and compressive deformation occurring in the systems and this, in turn, has enabled the differentiation between the structure and performance of the two semisolids. Keywords: Gel system; Gel strength test; Probe shape I. Introduction Gels are commonly used as vehicles for pharmaceutical and cosmetic preparations in many types of applications (dermatological, ophthalmic and intramuscular injectable). Gel formation is also involved in drug release from hydrophilic swellable matrices, which are widely used in prolonged medication (Colombo et al., 1987; Conte et al.,...
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...Module 1 Force And Friction A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of them. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction. Force is a quantity which is measured using the standard metric unit known as the Newton. [pic] For simplicity sake, all forces (interactions) between objects can be placed into two broad categories: • contact forces, and • forces resulting from action-at-a-distance Contact forces are those types of forces which result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces. Action-at-a-distance forces are those types of forces which result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces. For example, the sun and planets exert a gravitational pull on each other despite their large spatial separation. Even when your feet leave the earth and you are no longer in physical contact with the earth, there is a gravitational pull between you and the Earth. Electric...
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...SENIOR SECONDARY COURSE PHYSICS 1 (CORE MODULES) Coordinators Dr. Oum Prakash Sharma Sh. R.S. Dass NATIONAL INSTITUTE OF OPEN SCHOOLING A-25, INSTITUTIONAL AREA, SECTOR-62, NOIDA-201301 (UP) COURSE DESIGN COMMITTEE CHAIRMAN Prof. S.C. Garg Former Pro-Vice Chancellor IGNOU, Maidan Garhi, Delhi MEMBERS Prof. A.R. Verma Former Director, National Physical Laboratory, Delhi, 160, Deepali Enclave Pitampura, Delhi-34 Dr. Naresh Kumar Reader (Rtd.) Deptt. of Physics Hindu College, D.U. Dr. Oum Prakash Sharma Asstt. Director (Academic) NIOS, Delhi Prof. L.S. Kothari Prof. of Physics (Retd.) Delhi University 71, Vaishali, Delhi-11008 Dr. Vajayshree Prof. of Physics IGNOU, Maidan Garhi Delhi Sh. R.S. Dass Vice Principal (Rtd.) BRMVB, Sr. Sec. School Lajpat Nagar, New Delhi-110024 Dr. G.S. Singh Prof. of Physics IIT Roorkee Sh. K.S. Upadhyaya Principal Jawahar Navodaya Vidyalaya Rohilla Mohammadabad (U.P.) Dr. V.B. Bhatia Prof. of Physics (Retd.) Delhi University 215, Sector-21, Faridabad COURSE DEVELOPMENT TEAM CHAIRMAN Prof. S.C. Garg Former Pro-Vice Chancellor IGNOU, Delhi MEMBERS Prof. V.B. Bhatia 215, Sector-21, Faridabad Prof. B.B. Tripathi Prof. of Physics (Retd.), IIT Delhi 9-A, Awadhpuri, Sarvodaya Nagar Lucknow-226016 Sh. K.S. Upadhyaya Principal Navodaya Vidyalaya Rohilla Mohammadabad, (U.P.) Dr. V.P. Shrivastava Reader (Physics) D.E.S.M., NCERT, Delhi EDITORS TEAM CHAIRMAN Prof. S.C. Garg Former Pro-Vice Chancellor IGNOU, Delhi MEMBERS Prof. B.B. Tripathi Prof...
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...Answers to Conceptual Integrated Science End-of-Chapter Questions Chapter 1: About Science Answers to Chapter 1 Review Questions 1 The era of modern science in the 16th century was launched when Galileo Galilei revived the Copernican view of the heliocentric universe, using experiments to study nature’s behavior. 2 In Conceptual Integrated Science, we believe that focusing on math too early is a poor substitute forconcepts. 3 We mean that it must be capable of being proved wrong. 4 Nonscientific hypotheses may be perfectly reasonable; they are nonscientific only because they are not falsifiable—there is no test for possible wrongness. 5 Galileo showed the falseness of Aristotle’s claim with a single experiment—dropping heavy and lightobjects from the Leaning Tower of Pisa. 6 A scientific fact is something that competent observers can observe and agree to be true; a hypothesis is an explanation or answer that is capable of being proved wrong; a law is a hypothesis that has been tested over and over and not contradicted; a theory is a synthesis of facts and well-tested hypotheses. 7 In everyday speech, a theory is the same as a hypothesis—a statement that hasn’t been tested. 8 Theories grow stronger and more precise as they evolve to include new information. 9 The term supernatural literally means “above nature.” Science works within nature, not above it. 10 They rely on subjective personal experience and do not lead to testable hypotheses. They lie outside...
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...Holt Physics—Chapter 5: Work and Energy Price I. Section 5.1—Work A. Definition of work 1. Work does not mean the same thing in Physics as it does in the everyday sense of the word. 2. Work is defined as a force causing a displacement. Work = force x displacement W = Fd 3. Work is NOT done on an object unless the displacement is greater than zero 4. The only forces that are considered to do work are those that are parallel to the displacement. 5. For this reason we use our trigonometric functions to calculate forces applied at an angle. Insert Fig 5-2 6. Note that Θ is the angle between the applied force and the displacement. 7. Work is described in Newtons x meters (force x displacement). The unit of work is the Joule (J) 8. 1 Newton meter = 1 Joule 9. Work is a vector with both direction AND magnitude. This means WORK CAN BE NEGATIVE! 10. Negative work is most commonly used to slow an object down or decrease its velocity. II. Section 5-2: Energy A. Kinetic Energy 1. Kinetic energy is associated with an object in motion. 2. Kinetic energy depends on speed and mass Kinetic Energy = ½mv2 3. Kinetic energy is a scalar and will use Joules as...
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...Experiment 1 ------------------------------------------------------------------------------------------------------------------------------------------ Height=X Height=X In an ideal experiment: The ball rolls to the other side to the exact same height from which it was dropped from. In a real experiment: Forces of friction and gravity act on the ball so it rolls just short of the same height. In an ideal experiment: Ball rolls infinitely In a real experiment: Once again, forces of gravity and friction act on the ball to slow it. ------------------------------------------------------------------------------------------------------------------------------------------ Experiment 2 Cup has 0 net force. No gravity, No friction. An object with 0 net force will keep moving forever. Newton’s first law: Fnet=0 => V= constant or a=0 (velocity is constant, & acceleration is zero) ------------------------------------------------------------------------------------------------------------------------------------------Experiment 3 Question: Which string will break first? Top or bottom? Answer: Depends on how fast the force is applied. Reason: A massive object is harder...
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...judicial processes that take place for an ordinary drug bust, again informing the audience on how to avoid getting caught. During the second half of the video we further investigate how the DEA does a typical drug bust and we are informed to some of the horrors of these raids. Many times people who are suspected of being involved with drugs somehow become victims of the DEA planting drug evidence on innocent people who are of no real threat to society. These people are then forced to make a deal with DEA agents in order to eliminate or reduce sentence time in return for going undercover for the agency. In one case a young girl with a bright future ahead of her was killed in this line of action. DEA agents will refuse to admit that they force this dangerous work upon people. In the end I think the primary purpose of this film is to inform the audience of the endless drug war that has been going on for decades and how no good can come of it. Our money would be better spent helping addicts recover and setting up treatment facilities rather than funding the DEA which fuels a hopeless...
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...Porter’s 5 Forces Analysis = Suppliers, Customers, New Entrants, Substitute Products, Competitors What is Porter’s 5 Forces Analysis? Porter’s 5 forces analysis represents the competitive environment of the firm. It is a strategic foresight to avoid putting the competitive edge at risk and ensure the profitability of products on a long term. For the company this vision is quite important because the firm is able to direct its innovations in terms of choice of strategies and investments. The profitability of businesses within the industrial structure depends on the following forces: Competitive rivalry within the industry; Threats of new entrants; Threats of substitutes products; Bargaining power of customers; Bargaining power of suppliers. Golden Rules 6th force = Often the model is adjusted with a 6th force, the public authorities. This is important because the law and the norms can influence each of Porter’s 5 forces. Key factors for success = The key success factors of the environment have to be identified. To have a competitive advantage some strategic elements should be controlled. Threats of new entrants Public Authorities Bargaining power of suppliers Competitive rivalry within the industry Bargaining power of customers Threats of substitute products © Copyright 2008 LUXINNOVATION G.I.E., The National Agency for Innovation and Research in Luxembourg 1/2 Porter’s 5 Forces Analysis = Suppliers, Customers, New Entrants, Substitute Products...
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...mass of that body. • Determine if an object will float in a fluid based on its relative densities. So if you fill a tumbler up with water to the brim, put an object into it, weigh the water that has been pushed out of the tumbler, and compare that with the weight of the object, you'll know whether it floats or not. • Use the continuity equation and Bernoulli’s equation to explain common effects of ideal fluid flow. The pressure in a fluid moving steadily without friction or outside energy input decreases when the fluid velocity increases Assignment Requirements 3. Mass is the same, so if the whale is taking up less volume, the density must have increased. The whale has displaced a greater mass of water at the depth, so the buoyant force is greater. 20. Ice cubes float in water, and sink in alcohol. Anything with less density than the liquid that it's in will float. 22. It will increase 35. It would be harder on the top of a mountain because the pressure of the atmosphere is lower the higher you go. The atmospheric pressure pushes on the surface of the liquid when you suck which helps the liquid move up the straw. At sea level, the pressure is fourteen and a half pounds per square inch and reduces as you move higher. 43. When a steadily flowing gas flows from a larger diameter pipe to a smaller diameter pipe the speed of gas is decreases and pressure...
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