IB HL Chemistry Energetics - End of Topic Test 35 min 37 marks Answer all the questions in the spaces provided 1. What energy changes occur when chemical bonds are formed and broken? A. Energy is absorbed when bonds are formed and when they are broken. B.
Determine the number of moles of argon and the mass in the sample. 9. A 30.6 g sample of gas occupies 22.4 L at STP. What is the molecular weight of this gas? Think about it!!!!!
The strength of the intermolecular forces of attraction determines whether a substance will be a solid, a liquid, or a gas. It also determines the physical properties of a solid and liquids such as boiling point, surface tension, viscosity, and rate of evaporation. The two main intermolecular forces we dealt with are Hydrogen bonds and London dispersion forces. Procedure The digital thermometer was wrapped at the end with a piece of filter paper and secured with a rubber band. The thermometer was hanged from a test tube clamp on the ring stand.
Chemical Kinetics: Iodine Clock Experiment Bautista, Lance Ruther E., Tornalejo, Norielle Marie B. Abstract: Is Iodine clock really a clock? In what way do we relate temperature with the rate of the reaction? How about the relationship between the concentration and rate of reaction? In this experiment, the effect of concentration and temperature on the rate of a chemical reaction will be studied. For this experiment, when the temperature increases, collision between the particles also increases.
Since boiling point and vapor pressure are inversely proportional, the separation is thus based on the vapor pressure as well. In order for the distillation to be effective, the components of the solution must have significantly different boiling points, preferably between 30-40℃. In this experiment, hexane has a boiling point of 69℃, while toluene has a boiling point of 111℃. A liquid is heated to its boiling point and the vapors generated are condensed by cooling and collected in a receiving vessel. One vaporization and condensation cycle is called a theoretical plate.
Planck's constant: the constant relating the change in energy for a system to the frequency of the electromagnatic radiation absorbed or emitted, equal to 6.626 X 10^-34 J 5. Quantization: the concept that energy can occur only in discrete units called quanta 6. Photon: a quantum of electromagnetic radiation 7. Photoelectric effect: ejection of electrons from a substance by incident electromagnetic radiation, especially by visible light 8. E=mc^2: Einstein's equation proposing that energy has mass; E is energy, m is mass, and c is the speed of light 9.
One of the major sources of error in this experiment is that the volume of metal ball will rise while the surrounding water’s temperature rise. The metal ball has fixed amount of gas, so with higher volume the inner pressure of the metal ball will be lower. In order to reduce the error and improve this experiment, we can use a metal with lower coefficient of volume expansion. Objective: The objective of the second lab is to determine the relationship between the pressure and volume of gas with fixed temperature. Based on the Bayle’s Law, the pressure of the gas is inversely proportional to the volume with fixed temperature.
When the temperature falls below temperature of 980K, the structure is trigonal and posses the lattice boundaries a=b=c, α= β= γ ≠ 90°. The structure will transform from a α-model to the β-model and become a hexagonal unit cell. This then portrays the difference between the symmetries of the two different structures. According to Table 2, it shows the changes in cell parameters as well as volume in relation to the temperature of the metal. It therefore shows us that when temperature rises, the crystal forms will change as they are affected by changes in temperature.
Mr. Bodner states that French Physicists Jean Baptiste Perrin was the first to use the term Avogadro’s number. Based on his work on Brownian motion in 1909, Perrin reported an estimate of Avogadro’s number. To accurately determine Avogadro’s number requires the measurement of a single quantity on both atomic and macroscopic scales, with the use of the unit of measurement. This was possible because American Physicist Robert Millikan measured the change on an election. The charge on a mole of electrons for some time and is the constant called the Faraday.
The Practicum Exam: 1. All carbon copies will be collected at the end of the practicum. Put you name on the carbon copy! 2. Any student whose phone goes off during the practicum or has any other “noise” discharged from their phones, or any other electronic device, will be excused from the practicum and a zero will be recorded as their final score.