Enthalpy Values Essays

  • The Enthalpy Values for the Reaction Between Calcium Carbonate and Calcium Oxide with Hydrogen Chloride

    587 Words  | 2 Pages

    The Enthalpy Values for the Reaction Between Calcium Carbonate and Calcium Oxide with Hydrogen Chloride [IMAGE] H3 [IMAGE]CaCO3 (s) CaO (s) + CO2 [IMAGE] [IMAGE] H1 HCl H2 HCl CaCl2 (aq) Results ======= Variables of CaCO3 ================== Mass of CaCO3 + weighing bottle 3.302 g Mass of empty weighing bottle 0.831 g Mass of CaC03 used 2.471 g Temperature of acid initially 18 C Temperature of solution

  • Borax Synthesis

    881 Words  | 2 Pages

    This lab has a typical percentage error usually around 30%-40%. By looking at the percentage error of the calculated enthalpy and entropy, the percentage error is large but small when compared to the typical percentage error that is usually found in the lab. This typically large percentage error shows that there is an error in this lab that causes the experimental data to be less than the theoretical data. In this lab there were many opportunities that an error could have occurred and skewed the

  • Differential Scanning Calorimetry: DSC Analysis

    806 Words  | 2 Pages

    4A.2.9.2. Differential Scanning Calorimetry (DSC): DSC analysis measures the heat loss or heat gain resulting from physical or chemical changes within a sample as a function of temperature. DSC analysis was carried out to study the polymorphic transitions exhibited bythe SLN formulation. It was carried out for pure drug, bulk lipids L2 and L3 and the two lyophilized formulations. Thermal behavior of the developed formulation was studied using a differential scanning calorimeter (Universal TA Model

  • Comparing The Enthalpy Change Of Combustion Of Different Alcohols

    3136 Words  | 7 Pages

    Comparing The Enthalpy Change Of Combustion Of Different Alcohols The aim of my experiment is to investigate the enthalpy of combustion of a range of alcohols. The standard enthalpy of combustion is the enthalpy change that occurs when 1 mole of a fuel is burned completely in oxygen under standard conditions – 1 atmosphere pressure and 298K. All combustion reactions are exothermic which is why I am expecting all the values for the enthalpy change of combustion to always be negative. Prediction

  • Calorimetry Lab

    989 Words  | 2 Pages

    The objective of the lab is to determine the heat of the reaction between magnesium and hydrochloric acid in the calorimeter. To determine the enthalpy change of the chemical reaction, a calorimeter was placed onto the workbench. A balance was place on the workbench. The calorimeter was placed onto the balance and weighed to be 18.600 grams. A thermometer was attached to the calorimeter. The initial temperature recorded is 21.5 C. 50 mL of 1M of Hydrochloric Acid was placed into the calorimeter

  • The Activation Energy for the Molecule of HALS Reaction using GAUSSIAN 09 via the WebMO Interface

    877 Words  | 2 Pages

    on that , the transition state was not determine correctly while followed steps by using different format on it. Moreover, the energy of protonated nitrogen in the molecule was higher than where it was neutral. There also were different value in enthalpy of reaction with changing (R=H) level of theory and basis set. It can be suggested that changing the mechanism of HALS molecule can contribute stabilization obtaining transition state. 6.0 Acknowledgment I would like to thank my supervisor

  • Investigation into the Factors that Affect the Enthalpy Change During a Displacement Reaction

    1929 Words  | 4 Pages

    Investigation into the Factors that Affect the Enthalpy Change During a Displacement Reaction The Task -------- To investigate the factors affecting the enthalpy change during a displacement reaction. Background Knowledge ==================== In this investigation a displacement reaction will be observed. A displacement reaction occurs when more reactive metal displaces, (or removes) a less reactive metal from a solution of its salt. Also known as chemical bullying because

  • Chemistry: Magnesium Hydroxide And Citric Acid

    984 Words  | 2 Pages

    this lab we were measuring the change in temperature and how it affected the enthalpy of the reaction. 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

  • Determining the Enthalpy of Neutralisation for Three Acids

    1518 Words  | 4 Pages

    Determining the Enthalpy of Neutralisation for Three Acids [IMAGE]Determine the Enthalpy of Neutralisation for the following there Acids, H2SO4, HNO3 andH2SO4 Introduction Acid and bases have a very important property that is that they are able to cancel each other out when mixed together in the right proportions, this reaction is called a neutralisation reaction, which can be an exothermic reaction . The standard enthalpy of neutralisation is the heat absorbed per mole when an acid

  • Enthalpy Changes of Combustion of Different Alcohols

    1113 Words  | 3 Pages

    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 ---------------- Chemistry for you page 184 says, "breaking bonds requires energy, it is endothermic ". It also says " making new bonds gives out energy

  • Differential Thermal Analysis Essay

    3900 Words  | 8 Pages

    These reactions are studied using DSC. In case of carbohydrates a phenomena called gelatinization (A physiochemical transformation due to heat treatment of carbohydrates) is studied using the DSC as the DSC uses enthalpy changes to study the phase transformation during these reactions. Applications in liquid crystals: Liquid crystal is transient state between the liquid and solid transitions, in which the molecules has the orderly arrangement of solid crystals as

  • Reducing Ice Lab Report

    1115 Words  | 3 Pages

    chloride were compared to pure deionized water. The results of this experiment revealed that as more sodium chloride was dissolved, the freezing point depression increased. These values were anywhere from -1.14 and -4.51 degrees Celsius. Another strong indicator of sodium chlorides ability to deice roads is its enthalpy of dissolution. An exothermic reaction is preferred

  • Freezing Point Depression Lab

    748 Words  | 2 Pages

    ΔTf, was replicated for the 0.0, 0.4, and 0.6 concentrations. To find the freezing point depression, the equation ΔTf = imKf was used. The molality (m) of each solution was then calculated dividing moles of solute by kilograms of solvent, and the Kf value for magnesium chloride is known to be -1.86. Since magnesium chloride breaks down into three ions in deionized water, it was concluded that the Van’t Hoff factor couldn’t exceed three. For better accuracy, the experiment explained above for finding

  • Using Hess’s Law to Calculate Heat of Formation of of Magnesium Oxide

    1061 Words  | 3 Pages

    gained or lost in a chemical or physical change is the enthalpy change for the process, or heat of reaction. Heat of reaction can be calculated by using Hess’s Law which states that the heat released or absorbed in a chemical process is the same whether the process takes place in one or in several steps, also known the law of constant heat summation. By using Hess’s Law, the heat of reaction can be determined without actually measuring the enthalpy change. This is extremely helpful because some reactions

  • Calorimetry: Hess's Law

    682 Words  | 2 Pages

    REFERENCE General Chemistry for Engineering and Science II- pages 79-94 OBJECTIVES To practice obtaining measurements of calorimetry and to employ the data to demonstrate Hess’s Law of combining reaction enthalpies. QUESTION Did your experiment demonstrate Hess’s Law of heat summation? DISCUSSION For this experiment we have to know what Calorimetry, exothermic, endothermic, Hess’s Law, and calorimeter are. Calorimetry is the measurement of the quantity of heat exchanged. Exothermic is a chemical

  • Calorimetry Research Papers

    1052 Words  | 3 Pages

    also more expensive, so just in case you ever need one but don’t have one of these, there is a simpler, cheaper calorimeter consisting of two foam cups, a thermometer, a glass stirrer and a cork stopper. This one measures constant pressure and the enthalpy change during the reaction. Like I said above, t... ... middle of paper ... ... combustion of paraffin wax through the use of calorimetry, and I believe that that was met. It was met with finding the heat of combustion with a 7% error. It could

  • Thermodynamic Evaluation of PEM Fuel Cells

    1495 Words  | 3 Pages

    Chapter-V THEORITICAL ANALYSIS The performance of the PEM fuel cell is evaluated by a thermodynamic analysis, which is of two types, viz., energy analysis and exergy analysis. The energy analysis is made by applying the first law of thermodynamics to the fuel cell. The efficiency is defined by considering the heat input to the fuel cell and the work output from the fuel cell. In the exergy analysis the fuel cell and the surrounding environment are considered together. The efficiency is defined based

  • Enthalpy Changes of Combustion of Different Alcohols

    2115 Words  | 5 Pages

    Enthalpy Changes of Combustion of Different Alcohols Aim: The aim of this experiment is to find out how the enthalpy change (total energy released when the alcohols are completely combusted in a plentiful supply of air) for 5 different alcohols is affected by the number of carbon atoms in the alcohol and other factors contributing to the molecular structure. Prediction: I predict that as the amount of carbon atoms in the alcohol increases, the higher the enthalpy of combustion will

  • Algae as Renewable Energy Research Project

    1573 Words  | 4 Pages

    (Portugal), considered one of the world’s largest, having more than 4000 strains and 1000 species. This collection attests to the large variety of different microalgae available to be selected for use in a broad diversity of applications, such as value added products for pharmaceutical purposes, food crops for human consumption, and as energy source (Microalgae for Biodiesel Production and other Applications, 2009). Algal biofuels are generating considerable interest around the world. Microalgae

  • Investigating the Dfference in Enthalpy of Combustion for a Number of Alcohols

    3890 Words  | 8 Pages

    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