Required Materials: Solids: KNO3 unknown concentration, KNO3 Liquids: Tap Water, DI Water Other: 1 burette, 1 1000 mL beaker, 5 test tubes, thermometer, heating pad Objectives: • To determine the effect of temperature of the solubility of a salt. • To construct a solubility curve for the salt. • To determine the mass of an unknown size sample of the salt. Theory: Solubility is a measure of t he amount of one substance that can be dissolved in a measured amount of another substance. In this experiment we are going to measure the solubility of KNO3 in water at various temperatures.
1.1 Title: Investigating Viscosity 1.2 Research Question: How does varying the temperature (15 C, 30 C, 45 C, 60 C, 75 C) of 300cm^3 of cooking oil affect its viscosity, calculated by measuring the average velocity of a steel ball weight of 5g, falling through a 300cm^3 glass tube (25 cm in length)? 1.3 Scientific background: The intermolecular forces between the liquid molecules affect the viscosity of a liquid. As temperature increases, the intermolecular forces are weakening and some of them are overcome. Thus, the viscosity of cooking oil will decrease with an increase in temperature. As the liquid is more viscous, the ball weight would be experiencing more resistance in its motion and would thus have a lower average velocity.
If a curve were to run through the given data points, the curve was decrease less as time progresses. The difference in the temperature of the cooler is getting closer and closer. I would expect the cure to intersect the line T= 69.55 because the cooler is set at 58 degrees Fahrenheit. The lowest possible point the curve can intersect is at T= 58. The plastic starts at T=165.58 and will curve all the way down slowly below T= 69.55.
Some enzymes lose their activity when frozen. Some enzymes denatured when temperature increases too much, a potentially permanent process. Variables: Independent Variable: Temperature, 0°C, 15°C, 35°C, 45°C, 60°C. This is because it is the only thing we are changing over and over in the lab. Dependent Variable: The time taken in seconds the enzyme to react at different temperatures.
Catalysts operate by decreasing the value of the activation energy for the reaction. [1] The iodide ions lower the activation energy, making it easier for the reactants to convert to the products and vice versa, hence speeding up the reaction. We use an adaptation of the Arrhenius equation ln k’ = -Ea/RT + ln A . where k’ is the rate constant, Ea is the activation energy, R is the universal gas constant and T is temperature. [2] to determine the Activation Energy.
Contents Page Experiment 1 Calibration of a 25-mL Pipette 1 Experiment 2 Volumetric Analysis 3 Experiment 3 Experiment 4 Experiment 5 Gravimetric Determination of Nickel Sodium Acid Salt of Heptaoxodiphosphoric Acid Synthesis and Stoichiometric Analysis of Hexaamminenickel(II) Chloride 5 6 9 Experiment 1: Calibration of a 25-mL Pipette Background The graduation mark on a pipette being usually made at 20°C (whereas room temperature is much higher than this), the volume of the pipette must be calibrated before any volumetric analysis is carried out. Otherwise, the error in the graduation mark may exceed the error allowed in a measurement. A pipette is designed to deliver only one fixed volume of a liquid and it is calibrated for this volume only. Accuracy to two decimal places in mL is generally possible. The pipette is calibrated by weighing distilled water in it at room temperature, and then calculating the volume from the weight of water in air.
An approximate rule of thumb suggests that reaction rate - and hence the rate of heat generation - doubles with every 10°C rise in temperature. Thermal runaway can occur because, as the temperature increases, the rate at which heat is removed increases linearly but the rate at which heat is produced increases exponentially. Once control of the reaction is lost, temperature can rise rapidly leaving little time for correction. The reaction vessel may be at risk from over-pressurisation due to violent boiling or rapid gas generation. The elevated temperatures may initiate secondary, more hazardous runaways or decompositions.
In the case of α-phase FePO4, cell parameters tend to increase exponentially as temperature increase. The volume of the metal has the tendency to increase exponentially as well. It is governed by thermal expansion coefficient α (K-1)= 2.924 x 10-5 + 2.920 x 10-10 (T-300)2. There are two factors that affect the thermal expansions: 1. Angular variations due to the changes of Fe-O-P bridging angles.
For more concentrated solutions of hydrogen peroxide i.e. 7% to 10%, the sodium alginate bead did not reach the bottom of the measuring cylinder. It was suspended in the hydrogen peroxide for a few seconds, and then rose to the surface. Quantitative Data: A table showing the different concentrations of hydrogen peroxide and the time taken for each sodium alginate bead to rise Concentration of hydrogen peroxide/% | Time taken for bead to rise to the surface/s (±0.01) | Standard deviation | | Trial 1 | Trial 2 | Trial 3 | Trial 4 | Trial 5 | Average time taken/s | | 0 (control) | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 1 | 90.25 | 96.36 | 98.69 | 99.75 | 106.65 | 98.34 | 5.93 | 2 | 82.65 | 81.02 | 72.66 | 78.96 | 72.51 | 77.56 | 4.73 | 3 | 80.62 | 77.56 | 72.67 | 70.98 | 72.37 | 74.84 | 4.08 | 4 | 50.74 | 62.22 | 70.67 | 63.86 | 59.86 | 61.47 | 7.22 | 5 | 60.04 | 52.61 | 45.91 | 58.34 | 50.65 | 53.51 | 5.76 | 6 | 40.64 | 33.55 | 50.97 | 48.33 | 46.66 | 44.03 | 6.98 | 7 | 50.62 | 40.44 | 39.64 | 48.02 | 36.68 | 43.08 | 5.94
When bonds form, energy is required, hence the system will always lose energy. The energy lost will always be greater than the energy required to break bonds, this explains the negative change in enthalpy. Finally, the extra energy that is released from the excess energy lost from reaction will be released. This energy is usually released in a form of heat, causing the temperature to increase. Recording Raw Data: Quantitative Observation: Measurements of Water, Salt, and Mixture of the two Trial | Volume of Tap Water (mL) ±0.01 mL | Mass of Salt (g)±0.01 g | Initial Temperature (Ti) of water in the calorimeter ±0.1 °C | Final Temperature (Tf) of water in the calorimeter ±0.1 °C | 1 | 70.02 | 7.03 | 22.8 | 52.2 | 2 | 70.05 | 7.07 | 22.8 | 45.2 | 3