The second experiment is exothermic reactions because it gives out heat energy to the surrounding and energy is released more than it absorbed. It also has a negative energy change.
In terms of bonds breaking or forming, the first experiment its forming new bonds, because when alcohols are burnt, the reaction is always overall exothermic. Because more energy is released when new bonds are form than is being consumed.
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
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The reaction gives out energy. For example HCL + NaOH reaction form NaCl + H20, there is more bond making than bond breaking in this reaction so the H is negative, which it is more exothermic.
A neutralisation reaction will be an exothermic because it’s making bonds and produces lots of energy. If the HCL is to be concentrated it will contain more hydrogen and chloride ions. As a result of this there will be more bond making and so more heat will be produced as result. When heat is being produced it shows a reaction is take place and reaction between two solutions is when bonds are being made and gives out heat.
The second experiment result is different to the accepted value, as the experiment resulted in accepted value of 57.1kjmol-1 whereas the first experiment value of
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In polar covalent electrons are not shared equally because one atom spends more time with the electrons than the atom. Polar covalent create a dipole-dipole intermolecular. The force can create type of bond between polar molecules as well as hydrogen bond. This bond is not as strong as the other types of bond and it can be easily broken. for example water, the electrons are not shared equally between hydrogen and oxygen because oxygen is more electronegative than hydrogen.
ii) Polar dissolve in polar solvents and non-polar dissolve in non-polar solvents. This is because polar can molecules can undergo dipole-dipole force attractions. These electrostatic attraction between slightly positive and negatively charge poles of each molecules. However the non-polar can’t do this because they don’t have poles, instead they attract with other via dispersion force.
Temporary dipoles help dissolve simple covalent molecules in non-polar solvents. They are not very strong and the more electrons in the molecules the stronger the included
Aspirin is 3.3 g/L soluble in water (3). Aspirin can be soluble in ethanol, DMSO, or water (2). Aspirin has polar groups that when put with polar water molecules can form hydrogen bonds. Aspirin is an asymmetrical molecule. When drawing the Lewis Dot Structure, a person can see that the bonds are polar. There are also dipole moments making the molecule polar. Dipole molecules are composed of a higher electronegative atom pulling electrons towards it (11). It is more soluble in basic solutions than water and acidic solutions (4). The Lewis Structure also reveals that there are many double bonds between the carbons and two double bonds between oxygen and carbon.
Discussion: The percent of errors is 59.62%. Several errors could have happened during the experiment. Weak techniques may occur.
The data which was collected in Procedure A was able to produce a relatively straight line. Even though this did have few straying points, there was a positive correlation. This lab was able to support Newton’s Law of Heating and Cooling.
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.
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.
During this reaction the solution gained heat. This is what we were monitoring. The reason why the solution gained heat is because the reaction lost heat. Energy is lost when two elements or compounds mix. The energy lost/ gain was heat. Heat is a form of energy as stated above in the previous paragraph. The sign of enthalpy for three out of the four reactions matches what was observed in the lab. For the last reaction, part four, the reaction gained heat not the solution like parts one through three. The negative enthalpy value for part four indicates that the reaction gained
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.
For a reaction to occur, particles must collide. If the collision causes a chemical change it is referred to as a fruitful collision. (Hutchinson Educational Encyclopaedia, 2000) Enzymes increase the rate of exergonic reactions by decreasing the activation energy of the reaction. Exergonic reactions are those in which the free energy of the concluding state is lower than the free energy of the opening state.
Neutralization Experiment AIM:- To investigate how heat is given out in neutralizing sodium hydroxide (NaOH) using different concentrations of Hydrochloric Acid. Background Information:- Substances that neutralize acids are called alkalis. An acid is a substance that forms hydrogen ions (H+ ) when placed in water. It can also be described as a proton donor as it provides H+ ions. An example of an acid is hydrochloric acid (HCl), Sulphuric acid (H2SO4) etc.
Another way to control the heat is to decrease the distance between the boiling tube. and the container of the. The amount of energy released increases with the number of bonds. present in the chemical substance or fuel. That is because each bond has a certain amount of energy stored in it therefore the more bonds the more energy is stored and more energy is released if these bonds break through the combustion process.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
1-Butanol with intermediate polarity was soluble in both highly polar water and non polar hexane as 1-butanol can be either polar or non polar compound. 1-Butanol was polar based on the general rule of thumb stated that each polar group will allow up to 4 carbons to be soluble in water. Also, 1-butanol can be non polar due to their carbon chains, which are attracted to the non polarity of the hexane.
A catalyst is a substance that increases the rate of reaction without affecting the products of the reaction and remains unchanged. This experiment focused on increasing the temperature of hydrochloric acid when it reacts with magnesium. The volume of hydrogen gas produced. Independent variables: The temperature of HCl gas will decrease and increase throughout the experiment.
From these properties of bonds we will see that there are two fundamental types of bonds--covalent and ionic. Covalent bonding represents a situation of about equal sharing of the electrons between nuclei in the bond. Covalent bonds are formed between atoms of approximately equal electronegativity. Because each atom has near equal pull for the electrons in the bond, the electrons are not completely transferred from one atom to another. When the difference in electronegativity between the two atoms in a bond is large, the more electronegative atom can strip an electron off of the less electronegative one to form a negatively charged anion and a positively charged cation. The two ions are held together in an ionic bond because the oppositely charged ions attract each other as described by Coulomb's Law.