Berry List of Chemistry Experiments (PEKA) Form 4 (Part 1) Chapter 2 – The Structure of the Atom List of PEKA experiments: 1. Diffusion of particles in a gas, liquid and solid 2. Rate of diffusion depends on the temperature 3. Rate of diffusion depends on the mass of the gas particles 4. Melting and freezing points of naphthalene, C10H8 Number | Activity 2.1 | Pg.
Alkanes - CnH2n+2 Trends in melting point, boiling point and volatility can be explained by the weak intermolecular forces called induced dipole - induced dipole forces (van der Waal's forces). As the chain length of alkanes increases, so does the number of electrons, which increases the strength of the van der Waal forces. Branching reduces the surface area over which induced dipole - induced dipole forces can act. Alkanes are non-polar molecules, so do not react with polar reagents. Free radicals are produced by the homolytic fission of covalent bonds, for which light can provide energy.
Energetics Aim: To measure the energy released from the complete combustion of a known mass of alcohol or paraffin wax, to heat water. Hypothesis: The combustion of alcohols is exothermic. In this experiment the energy is released from burning a known mass of alcohol in order to heat a known amount of water. A comparison of various alcohols and paraffin wax (methanol, ethanol, propanol, butanol, octanol and candle) as fuels can be made by calculating the quantity of energy transferred to the water. In this experiment, the amount of energy (heat) involved in a chemical change will be determined.
Gas Laws A gas law is described as a mathematical generalization of the relationships among the amount, pressure, temperature, and volume of a gas (p 168). Boyle’s law p. 168 Of the several relationships that exist among gas law variables, the first to be discovered relates gas pressure to gas volume. It was formulated over 300 years ago, in 1662, by the British chemist an physicist Robert Boyle. Boyle’s law states that the volume of a fixed mount of a gas is inversely proportional to the pressure applied to the gas if the temperature is kept constant. This means that if the pressure on the gas increases, the volume decreases proportionally; conversely, if the pressure decreses, the volume increases.
4. Results and Discussion Specific heat capacity refers to the amount of heat needed to raise or lower the temperature of a substance. This amount of heat is directly proportional to the mass of the material. In the first activity, the specific heat of a metal, in our case aluminum, was calculated (Table 1). The following formula was used: cm=mwcwT3-T1+mcccT3-T1 mmT2-T3 Where cw is the specific heat capacity of water and cc is the specific heat capacity of calorimeter.
University of Alabama in Huntsville Math 201 Section 1, Spring 2008 Final Exam: MATH 201 Section 1 Full Name: ................................................................................................ Student ID Number............................................................. Note: You need to SHOW all your WORK in order to have full CREDIT. The use of CALCULATOR is prohibited during the exam. There are 10 problems (30 points each ) on the Exam and one bonus problem worths 40 points on this Final Exam. Read each question carefully The Final is 2 and 1/2 hours long or 150 minutes Homework and Quizzes: 150 pts Midterms: 550 pts Final Exam : 300 pts Final Grade over 1000 Letter Grade Note that you need at least 600/1000 to make a grade of C − .
Molecular Weight by Dumas Method In your text (Chang, 10th Ed) : 5.4 The Ideal Gas Equation, especially the Density and Molar Mass of a Gaseous Substance subsections Purpose: The experimental determination of the molecular weight of a volatile liquid sample and the density of its vapor are used to illustrate the uses of the Ideal Gas Law. Background: The Ideal Gas Law is: PV = nRT (Eqn. 1) where P = pressure in atm, V = volume in L, T = temperature in K, and R = 0.082056 L atm/(mol K), the Gas Constant It describes, with good precision, the behavior of many real gases over a wide range of pressures and temperatures. Even when there is deviation from ideality, it is useful as a starting point in physical analysis Recalling that density is mass/volume, Eqn. 1 can be re-written to derive the equation for the density of a gas, assuming ideal behavior: n = P Now multiply both sides by MW: n(MW) = P (MW) V RT V RT n(MW) is # moles x grams/mol = grams = mass, m Therefore: m = (P)(MW) = d , density (mass/volume, in grams/ liter ) (Eqn.
1 q= Cs x g x T Q represents heat. Specific heat (Cs) is multiplied to the mass (g) and temperature change that occurred in the reaction. ( T). Specific heat is defined as the amount of energy required to raise the temperature of 1 g of a substance by 1 K, under a constant pressure. Considering the fact that substances have differences, the specific heat varies depending on what substance is being heated.
PU11 Physics Question Bank – Heat & Thermodynamics One mark questions 1. In a Carnot engine, the temperature of the sink is 27 C and that of the source is 327 C . What is the efficiency of the Carnot engine? Ans: 1 2. T2 273 27 300 1 1 1 T1 273 327 600 2 How is the efficiency of a Carnot engine affected by the nature of the working substance?