The objective of this experiment was to investigate the relationship of dispersion forces and hydrogen bonding forces in intermolecular attractions through the evaporation of different substances. Using temperature probes, the endothermic process of evaporation is measured by inserting the probes into the substance and then taking them out to allow the substance to evaporate, the change in temperature of the substances showed if a lot or not a lot of evaporation occurred and over how long the evaporation took place depending on if the change in temperature was high or low.
Figure 1 compared the change in temperature in Celsius during evaporation for ethanol and 1-propanol over a time period in seconds. Due to its higher molecular mass, 1-propanol (60.09 g/mol) was harder to evaporate than ethanol (46.06 g/mol). Both substances had very low changes in temperature because of their hydrogen bonds and dispersion forces as well as relatively high molecular masses, those factors made it hard to break their bonds and make them evaporate.
Figure 2 shows the process of evaporation for 1-butanol - an alcohol, and pentane - an alkane. In this figure a big difference in temperature change can be seen between the two substances. Due to its hydrogen bonds and dispersion forces, 1-butanol had a smaller temperature change compared to pentane, the hydrogen bonds of 1-butanol made it much harder to pull its molecules away from each other, thus making it evaporate slower. Since pentane only has weak dispersion forces it evaporated much faster once the probe was taken out of the test tube and had a higher change in temperature.
Figure 3 illustrates the change in temperature during evaporation for the alcohol methane and the alkane hexane. The ...
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...ces and high molecular weights make a substance harder to evaporate, while weak intermolecular forces and low molecular weights make it easier to evaporate, resulting in a change in temperature that was either low or high. Possible errors that could have occurred during the experiment could be from incorrectly calibrating the temperature probes at the start of the experiment, which would throw off the temperature readings and make them too high or too low. Another error could have come from starting the data collection too late and missing the beginning of the evaporation, thus resulting in a maximum temperature that was too low and a change in temperature also too low. Also, two of the test tubes had to be rinsed to be used for the second part of the experiment and water could have clung to the inside of the test tube and contaminated the substance put inside it.
Hypothesis- Water will evaporate the quickest because there isn't heavy sugars in the drinks slowingdown the evaporation process.
An Investigation Into How the Thickness of Insulation Affects the Time a Drink Takes to Cool Down
The mean for the temperatures is 0.116 and the solvents is 20. We predicted the 37 Celsius would be the most absorbed, but it was the -20 Celsius which can be seen in the graph above.
To investigate the relationship between three different alkanols in terms of their carbon chain length, rate of increased temperature, and heat of combustion, in order to determine which is the most efficient at heating water to a certain temperature whilst reducing time and effects on the environment.
The hypothesis for this experiment was, If three different types of waters (saltwater, fresh water, tap water) are tested, then the liquids won’t evaporate at the same rate and tap water will evaporate at the fastest rate because it won’t have any non-volatile substances to hold it back from evaporating.
EG, if the water was 23 degrees I would heat the water to 33 degrees. Make sure that the fuel is weighed correctly after experiment, and recorded. By doing these checks, it means that all the experiments will be fun the same. This means the test will all be fair. Prediction I think the more bonds in the alcohol molecule structure means that more heat energy will be produced when the bonds are broken and so less fuel will be used, as the heating temperature will be higher, so it will not take as long to heat.
Alcohol particles break their bonds when they mix with oxygen. This is known as an exothermic reaction. Boiling points will be increased because energy is needed, bonds can be formed and broken. Breaking bonds need less energy than is needed to form bonds - an exothermic reaction. Bigger molecules use high energy to break down.
The molar mass of butane gas (C4H10)can be obtained theoretically by using a periodic table, but by rearranging the ideal gas law equation (PV = nRT) to n =PVRT, the experimental molar mass of butane gas can be found. In the equation, P= pressure in atmosphere, V= volume in liters, n= moles, R= 0.0821, and T= temperature in kelvin. To find the values for the equation, the mass of the butane released from a pressurized container and the volume of that gas will be found, and the method of water displacement at room conditions will be used to find the rest of the values. Then, the molar mass will
Dissolvability is most prominent between materials with comparable polarities and this is characterized by hydrogen
This software enables you to simulate experiments. This means that I am able to quickly carry out experiments to help in planning for my investigation. ---------------------------------------------------------------------- Alcohol Temperature Increase (oC) Mass of burner before exp. (g) Mass of burner after exp.
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.
The last part of experiment 5, was learning about specific gravity and temperature. Specific gravity does not have any units, it is unitless. When measuring for the temperature, we used a thermometer to calculate the Celsius of the water, 10% sodium chloride, and isopropyl alcohol. The specific gravity uses a hydrometer to measure the gravity of the liquids. Using the hydrometer, to figure out the measurements we have to look at it from top to bottom. The water for specific gravity was .998 while the temperature of it was 24
The rate of evaporation can increase if the gas pressure decreases around the liquid. Heat energy is used to break the bonds that hold water molecules together, that is why water easily evaporates at the boiling point but evaporates much slower at the freezing point. Net evaporation happens when the rate of evaporation surpasses the amount of condensation. Saturation occurs when these two process rates are equivalent when the humidity of the air is at one-hundred percent. On average, a fraction of the atoms in a glass of water has enough heat energy to escape from the liquid. Evaporation from the ocean is the primary device for supporting the surface-to-atmosphere part of the water cycle. Evaporation is the pathway where water moves from the liquid state back into the water cycle as atmospheric vapor. Studies have shown that the major bodies of water are nearly ninety percent of the moisture in the atmosphere from the evaporation of the water, the ten percent left is contributed from plant transpiration. Evaporation can only occur when water is available. It also requires the humidity of the surrounding atmosphere to be less than the evaporating surface. At one-hundred percent relative humidity, there is no more evaporation. The wind chill effect is one of the
On further cooling the χT curve shows a sudden increase to 1.23 cm3.K.mol-1 at T=21 K followed by a sharp decrease down to 0.71 cm3.K.mol-1 at 5 K. The χT maximum de...
As air humidity is in an instance of increasing, its ability to absorb water vapor decreases and evaporation rate slows down. For evaporation to undergo there must be a difference in humidity (Tenalem Ayenew and Tamiru Alemayehu, 2001; Fetter C.W, 1994).