Background Information: Alcohols are a family of organic compounds containing the hydroxyl (-OH) functional group. In this experiment the five different alcohols used will be: Methanol1 Ethanol1 Propan-1-ol1 Butan-1-ol1 Pentan-1-ol1 As can be seen from the structural formulae above, as one moves down the homologous series carbon atoms are added to the hydrocarbon chain and therefore the number of carbon atoms increases. …show more content…
Calculating the Enthalpy change during Combustion: The formula for the Enthalpy change during combustion is ∆H = mc∆T Where ∆H is the enthalpy change during combustion measured in joules, m is the mass of the water in grams, c is the specific heat capacity of water the ∆T is the change in the temperature in kelvin. Therefore, Enthalpy change during combustion= 100g x 4.18 J g-1 K-1 x 40K = 16720 J 6. Calculating the Enthalpy change of Combustion: The Enthalpy change of Combustion of Methanol is the enthalpy change per mole. Therefore the result above must be divided by the number of moles of methanol …show more content…
Calculating the Uncertainties in the measurements: Uncertainty in the mass balance = 0.001 g Mass of methanol burnt = 3.132 g ± 0.002g Percentage Uncertainty = 0.002 g x 100 % 3.132g = 0.063 % Uncertainty in the thermometer = 0.1 ̊C Temperature Difference = 40.0 ̊C ± 0.2 ̊C Percentage Uncertainty = 0.2 ̊C x 100 % 40.0 ̊C = 0.5 % Uncertainty in the measuring cylinder = 0.5 cm3 Volume of Water taken = 100 cm3 Percentage Uncertainty = 0.5 cm3 x 100% 100 cm3 = 0.5 % To calculate the total uncertainty all the percentage uncertainties calculated above must be added, = 0.063 % + 0.5% + 0.5% = 1.063% To find out the uncertainty in the enthalpy change of combustion of methanol 1.063% of 171.1 kJmol-1 must be taken. = ± 1.818 kJmol-1 The same procedure was used to calculate the enthalpy change of combustion for the other alcohols used in this experiment and their
Another simple improvement to the experiment could have been the addition of time to procedure A as well as possibly increasing the time heated under reflux. Since the entire procedure B had to be completed before the period of reflux was done, some of the steps and processes involved in procedure B were rushed or not given the adequate time allowed to produce the best sample of product. In general, the laboratory experiment was successful and turned out well to find that the bromide ion was the better nucleophile to both the n-butyl alcohol as well slightly toward the t-pentyl alcohol used in the
The purpose of the lab is to understand how to calculate the calorimeter constant by using a calorimeter. This allows us to analyze the heat reaction of different substances. Calorimetry is a word that comes from both Latin and Greek. The prefix “Calor” in Latin signifies heat and the suffix “metry” in Greek means measuring. Therefore the word itself translates to measuring heat. Joseph Black, was the first scientist to recognize the difference between heat and temperature. Energy is always present in chemical and physical changes. The change of energy that occurs when there is a chemical change at constant pressure is called enthalpy. Enthalpy changes , as well as physical and chemical changes, can be measured by a calorimeter. The energy that is released or absorbed by the reaction can be either absorbed or released by the insulating walls of the instrument.
Materials of different types will exhibit varied changes in temperature when transferred the same amount of heat. This variation is a result of the difference in properties displayed from one material to another, known as "heat capacity." Every substance has a variable, positive valued heat capacity that represents the amount of heat required to initiate a specific temperature change. (Hechinger, page 1) For ideal gases, there are heat capacities at constant volume and constant pressure given by:
What this means for the reaction is that there isn’t as much bonds being produced which will ultimately affect the amount of energy released in the form of heat, thus decreasing the overall heat of combustion whilst also effecting the reliability of the calculations.
Comparing the Enthalpy Changes of Combustion of Different Alcohols Aim Combustion of alcohols is exothermic; energy is given out. Salter's Chemical storylines says, " Different fuels have different enthalpy changes". I will investigate how the carbon chain length of the alcohol affects its enthalpy of combustion. Preliminary Work ----------------
It is also possible for the alcohol product to be prepared from another combination of halides and ketones than the ones used for this experiment. For example, using methyl bromide and 2-heptanone. The Grignard reaction for these starting materials is shown
If I compared my result to the literature values, are by no means accurate. But I could not have made the experiment completely efficient in the heat transfer. However, the results were all similar for each alcohol, without the small number of anomalous results. This means that the experiment was reliable, but the values were
In summary, the results suggested that as the carbon chain increases in alcohols, the shorter the flame. The results also suggested that if the flame length increases, the enthalpy increases as well in a linear function. It can be said that the experiment that investigated whether the longer the carbon chain length would increase enthalpy is either invalid or not accurate. This can be the case as the theory should be correct as there are extra bonds that need to be broken which in turn will release more energy. Recommendation to improve the design to gather better results were made. Nevertheless, the experiment produced some results and provided further areas of research and
...e is of the same sort as the exhaust temperature. Alteration of liquid hydrocarbons into gas must develop the burning process. Several doubts still stay on the expenses and the technical capability of the catalytic cracking process. If a division unit is necessary to separate the unreached part of the product stream from the gaseous hydrocarbons, the system will turn out to be more expensive. Though, if vaporization suffices, no additional apparatus will be needed.
The purpose of this experiment is to try to find the original temperature of the hot water in the heater using the 60 degrees C thermometer. Use your 60°C thermometer, and any materials available in your laboratory, to determine the temperature of the water in the coffee pot. During this experiment we calculated the original temperature of a heater after it had been cooled down, and we did this by measuring hot, cold, and warm water, with a thermometer that had tape covering 60 degrees and up. When preformed each of these experiments with each temperature of water, plugging them into the equation (Delta)(Ti – hot – Tf) T Hot x Cp x Mass(Cold) = (Delta)(Tf – Ti – Cold) T Cold x Cp x Mass(Hot)(d
First, a calorimeter was constructed with three standard styrofoam cups. One cup was stacked within the second for insulation, while the third cup was cut in half to be used as a lid. The lid was made to increase accuracy when recording the temperature. The temperature probe hooked up to Logger Pro software poked a hole in the top of the calorimeter by applied force with the end of the probe through the Styrofoam. Meanwhile, 40mL of deionized water were measured out in two clean 50 mL graduated cylinders, and poured into 100 mL beakers. The beakers and graduated cylinders were cleaned with deionized water to avoid contamination that may cause error. One of the beakers was placed onto a hot plate, which was used to heat the water in the beaker. The other beaker rested at room temperature. Once heated and at room temperature, the initial temperature was measured with the probe. Next, the two 40 mL of deionized water were poured into the calorimeter, quickly sealed with the lid, and the temperature probe emerged through the top of the calorimeter into the water to measure the temperature so the calorimeter constant would be determined. The equations used to determine the calorimeter constant were Δq = mCΔT and Δq =
Incomplete combustion occurs when a fuel reacts with oxygen to produce carbon monoxide (CO), water (H2O) and carbon (C). This form of combustion releases less energy from the reaction that complete combustion, as it does not consume the fuel entirely. The chemical equation for incomplete combustion of acetylene gas is:
This is expressed as Δ +ve (delta positive). If the total energy put in is less than the energy created, then the substance warms up (it is exothermic). This is expressed as Δ -ve (delta negative). I will investigate eight different alcohols using an alcohol or spirit burner, to measure the energy change during burning by measuring the change in temperature of some water held in a container.
In part one of this calorimetry experiment, the heat gained by the system, the sausage, was lost by the surroundings, the water. This relates to the 1st Law of Thermodynamics that states “energy can neither be created nor destroyed”. In parts two and three of this experiment, the heat generated by the reaction was transferred to the solution. The first the first calculation I had to perform was finding the specific heat capacity of the sausage by using the formula, m_water C_(p,water) 〖ΔT〗_water+m_sausage C_(p,sausage) 〖ΔT〗_sausage=0 that is derived from the formulas q_(water=) 〖-q〗_sausage and q=mC_p ΔT. This value, which is the amount of energy in Joules that it takes to raise one gram of the sausage by 1°C, was then multiplied by the number
Small samples of each brand of cold drinks were taken in separate test tubes and Iodine followed by Potassium Iodide and Sodium Hydroxide (NaOH) solution was added to each test tube. Then the test tubes were heated in hot water bath for 30 minutes. Appearance of yellow coloured precipitate confirmed the presence of alcohol (ethanol) in cold drinks.