Investigate the difference in enthalpy of combustion for a number of alcohols Enthalpy I am going to investigate the difference in enthalpy of combustion for a number of alcohols, the enthalpy of combustion being the 'enthalpy change when one mole of any substance is completely burnt in oxygen under the stated conditions'. I will be attempting to find how the number of carbon atoms the alcohol contains effects the enthalpy change that occurs during the combustion of the alcohol. Method I plan to measure the enthalpy change by burning the alcohol, using a spirit burner, I will then use the heat produced during the combustion of the alcohol to heat 100ml of water that will be situated in a copper calorimeter directly above the burning alcohol. The calorimeter is made of copper as copper has a high thermal conduction value, this basically means that it is a good conductor of heat so a lot of the heat the copper receives will be passed on to the water which I am then able to measure. During the experiment I will be taking a number of measurements, I will firstly take the initial temperature of the water and initial mass of the alcohol I will then burn the alcohol until an increase in temperature of 20oc has occurred in the water I will then reweigh the alcohol. The measurements [Mass of alcohol burned (g), Temperature increase (oc)] will tell me what mass of alcohol is used during combustion to cause the temperature increase of 20oc in the water, I can then work out the energy released per mole and compare these values and see which has the highest enthalpy of combustion. I will need to repeat my experiment a number of times and take an average so I am sure of an accurate result. The set up of the apparatus as you can see is v... ... middle of paper ... ...s within the alcohol affects the enthalpy of combustion. I did have an idea on how to further increase the accuracy of my results but I did not have time to put in to practice. I thought that I could make something that directed more of the heat produced towards the apparatus. A sketch of it is shown below. This would keep more of the heat produced during combustion close to the calorimeter so more is absorbed. Lining the reflector with silver/ shiny surface would also mean a lot more of the heat is kept in the apparatus so that I am able to measure it. There are other aspects of the enthalpy of combustion of alcohols that I could have also investigated. Firstly I could have looked into whether the position of the OH group within the molecule effects the enthalpy change and also whether branching within the molecule also has any effect on the enthalpy of combustion.
Thermodynamics is essentially how heat energy transfers from one substance to another. In “Joe Science vs. the Water Heater,” the temperature of water in a water heater must be found without measuring the water directly from the water heater. This problem was translated to the lab by providing heated water, fish bowl thermometers, styrofoam cups, and all other instruments found in the lab. The thermometer only reaches 45 degrees celsius; therefore, thermodynamic equations need to be applied in order to find the original temperature of the hot water. We also had access to deionized water that was approximately room temperature.
The change in enthalpy for the combustion of magnesium metal. Abstract = == ==
Sun L. et al studied the thermal stability and fire retardant properties of wood flour/polypropylene composites containing magnesium hydroxide (MH), expandable graphite (EG), and ammonium polyphosphate(APP) as flame retardant. The results showed that both expandable graphite and ammonium polyphosphate promoted thermal degradation of wood flour and char formulation, and magnesium hydroxide did not influence on the wood flour decomposition. Cone calorimeter results indicated that EG showed the best properties on fire retardant and suppression smoke
If the length of the carbon chain within an alkanol is increased, then the heat of combustion will also increase due to a greater amount of intermolecular forces between molecules, as there are more carbon-hydrogen molecules being added to the homologous series. Thus the amount of energy required to break those bonds will be much higher, causing a greater amount of energy being released during the reaction. Therefore enhancing the mass of the hydrocarbon and change in enthalpy which will consequently increase the heat of combustion.
From working out how much fuel has been used, I can work out how much bond energy has been released from the molecules of the alcohol. From those results I will be able to say which alcohol is the best for combustion and which one is the worst to combust. A good fuel should produce a lot of heat energy and use a small amount of fuel. (economical) A bad fuel uses a lot of fuel and produces less heat energy.
water has risen to 60°c I will then put the lid on the spirit burner
Specific heat capacity of aqueous solution (taken as water = 4.18 J.g-1.K-1). T = Temperature change (oK). We can thus determine the enthalpy changes of reaction 1 and reaction 2 using the mean (14) of the data obtained. Reaction 1: H = 50 x 4.18 x -2.12.
The Enthalpy Change of Different Alcohols My aim is to compare the enthalpy change of combustion of different alcohols in relation to the structure of each molecule. The enthalpy change of combustion of a fuel is a measure of the energy transferred when one mole of the fuel burns completely. In a chemical reaction, bonds must either be made or broken, this involves an enthalpy change. The formation of bonds is exothermic, energy is lost to the surrounding; on the other hand, breaking bonds is endothermic, energy is taken in. I obtain the value for the enthalpy change of each fuel by using the formula: Energy transferred from the fuel=
For this experiment, you will add the measured amount of the first sample to the measured amount of the second sample into its respectively labeled test tube then observe if a reaction occurs. In your Data Table, record the samples added to each test tube, describe the reaction observed, if any, and whether or not a chemical reaction took place.
Experimental Summary: First, my partner and I put the marshmallow and cheese puff on T-pins and used the Electronic Balance to measure the mass of each of them. Next, we put 100 mL of water in the 100 mL Graduated Cylinder and poured it into the 12 oz. soda can. We measured the temperature of the water with the thermometer. After
Measure and record the temperature of the water in the Styrofoam cup. Leave cardboard cover on until the heated metal is ready to be transferred into the calorimeter.
Investigating Factors Affecting the Heat of Combustion of Alcohols PLANNING SECTION Introduction ------------ Alcohols are organic substances, and consist of Hydrogen, Oxygen and Carbon. All alcohols are toxic but the amount that can be tolerated by the human body varies for different alcohols. For example drinking small amounts of Methanol can lead to blindness and even death.
This container must have a value of specific heat capacity so I can calculate heat transferred to it as well. Probably the most conductive container available for use in the classroom is a calorimeter. As well as not wasting energy on the heating of the container, I could also try to stop heat from escaping the top and edges of the container by covering it with a fitting lid. I will try to prevent the wind from blowing the flames in a different direction so all the windows must be shut. HYPOTHESIS More energy is released as more bonds are formed, below is the list of approximate energy required to break and form all bonds involved in burning alcohols.
There are three types. of heat: conduction, convection and radiation. There are a number of ways to control the heat lost, an example is taking tiles and. surrounding the fire to decrease the area of the heat that can be lost. so more heat is trapped in the water.
The heating rate of biomass for fast pyrolysis can be high as 1000°C/s- 10,000°C/s, however maximum temperature for the process is maintained below 650°C. the primary interest is to produce for tis process is to produce bio-oil, however temperature can be increased up to 1000°C produce fuel gases in the same process (Table 1). There are 4 important factors that can affect the liquid yield heating rate, reaction temperature, residence time and rapid quenching of the product gas. Maintaining these factors can increase the liquid yield of biomass and maximize the production of bio-oil.