Enthalpy Essays

In the lab the goal of measuring the specific heat of NaOH and the enthalpy change of a neutralization reaction between NaOH (strong base) and HCl (weak acid) was accomplished. This was accomplished by finding the heat of solution of the salt and measuring the heat capacity of the calorimeter to measure the enthalpy. During this lab one of the assumption that was made was the law of conservation of energy. Specifically, the loss of heat is equal to heat gained. The heat of solution with the assumption

Patriciah Mulinge Lab Partners: Rachel Reagan, Heaven Wolde Chem:117 TA Daniella Graf Stillfried Station 2 4/6/17 Heats of Reaction  Abstract In Physical Chemistry, the bridge between chemistry and physics, usually begins with the study of thermal energy, otherwise called heat. Most reactions either release or consume energy. This loss and or gain of energy can be referred to as either Endothermic-gaining heat, or exothermic- losing heat. it is imperative that chemists understand thermal energy

The Calorimetry experiment is the use of a calorimeter to measure a temperature change. Calorimetry is the measurement of heat.1 This can later be used during calculations to find the enthalpy of an equation. Essential to calorimetry is the calorimeter, which can be any device for accurately measuring the temperature of a substance before and after a change occurs.2 A calorimeter can be as simple as a styrofoam cup. Its quality as an insulator, which makes styrofoam ideal for holding in the warmth

was used in the experiment to determine the standard heat of combustion and formation of naphthalene. The heat capacity, C(s), of the bomb calorimeter obtained from a standard benzoic acid combustion was 10792.3±184.651 J/℃. Using this C(s), the enthalpy of combustion (∆Hcombust) of naphthalene was determined to be -5134.96±33.3433 kJ/mol. The final standard formation ((∆Hf, C10H8。) of naphthalene was 56.438±33.3433 kJ/mol, which was not very close to the theoretical value. Since only two runs were

Research Question: How does the reactivity of a Metal affect the enthalpy change for a reaction? Aim: To investigate how reactivity’s of various metals (Fe, Mg, Zn, Cu and Mn) affect the enthalpy change of the solution when it reacts with 25cm3 Copper II Sulphate. Theory: Specific heat capacity is the amount of energy needed to raise the temperature of one gram of a substance by 1 degree Celsius. Different materials absorb different amount of heat when their

Problem: Can the specific heat of an unknown metal be found using calorimetry? Background: Calorimetry is the science of measuring heat based on observing the change of temperature when a body takes in or gives off energy as heat or light. The device used to determine heat associated with a chemical reaction is called a calorimeter. When calorimetry is used it’s information is then put into an equation to find the specific heat of an object. The equation is, SMΔTwater=SMΔTobject. This means that

Polar bears have a thick layer of fat called blubber which is about 11 cm thick. This also helps the bears to survive in the freezing conditions. Not only on land, but the thick layer of fur coat and blubber helps them as they spend a great amount of time swimming in the freezing waters of the Arctic. Blubber is a thick layer of fat that helps prevent sea mammals from getting too cold. Blubber in depth, is an extra digested food stored in the form of adipose tissue, which contains molecules called

Purpose: The purpose of this experiment is to investigate the changes in temperature one meter above the ground along an environmental gradient of one meter. The data will be take using increments of one meter from a wall. Introduction: An environmental gradient is a gradual change in abiotic factors through space (or time). Environmental gradients can be related to factors such as altitude, temperature, depth, ocean proximity and soil humidity. In this experiment the envionrmental gradient is

Chemical reactions which cause a change in temperature can be categorized as endothermic or exothermic reactions. In an endothermic reaction, energy will be absorbed by the chemical mixture; in an exothermic reaction, energy will be released. If a beaker is submerged in a mixture with a cooler temperature than the water inside the beaker, heat will be transferred from the water in the beaker to the chemical mixture, making the chemical mixture undergo an endothermic reaction. When the chemical mixture

This practical report presents the molar enthalpy of combustion of several alcohols. Alcohols The most abundant form of organic compounds is alcohol, alcohol is formed by an OH- combining with a carbon atom. These compounds can be put into three groups, primary, secondary and tertiary the distinction for identifying which classification these compounds are, is dependent on the way the hydroxyl is covalently bonded with carbon. In primary one carbon is only bonded with another carbon, secondary has

Enthalpy of neutralization The purpose of this experiment is to determine the enthalpy change for the reaction between aqueous sodium hydroxide (NaOH) and aqueous hydrochloric acid (HCl). Introduction A neutralization reaction is a chemical reaction where a base and an acid react with each other. The products will always be water and a salt. The balanced reaction equation for this experiment is the reaction below (Enthalpy of neutralization, 2018). 〖NaOH〗_((aq))+〖HCl〗_((aq))→〖NaCl〗_((aq))+H_2 O_((l))

to Chem Practice Experiment 3-Enthalpy of Chemical Reaction Dana Lucas Robin Brown TA: Chris February 19, 2018 Introduction The purpose of this experiment was to calculate the change in enthalpy of 2 reactions using Hess’ Law by using a coffee calorimeter to measure the temperature changes in the sub reactions for MgO and a neutralization reaction. Germain Hess published this law in 1840, which described the first law of thermodynamics. In Hess’ Law, “the enthalpy change in a chemical reaction

Prediction Purpose The purpose of the investigation is to use calorimetry in order to determine the molar enthalpy of combustion of magnesium by using Hess’s Law. Question What is the molar enthalpy of combustion ∆Hc, of magnesium? Materials Investigation 4.5.1 Pg. 351 Eye protection Steel wool Magnesium oxide powder 10 to 15cm strip of magnesium ribbon 100mL graduated cylinder 1.00 mol/L hydrochloric acid 3 Styrofoam cups (calorimeter) Eye dropper Mass scale GLX temperature

submission: 01/12/2014 Comparing the Enthalpy Changes of Combustion of Ethanol (CH3CH2OH) and Butanol(CH3CH2CH2CH2OH) in order to determine which one of them that is the more efficient as a fuel. Objective The purpose of this lab is to determine the fuel efficiency of the two alcohols Ethanol and Butanol, by comparing their respective enthalpy changes. The most efficient fuel will be the one with the highest enthalpy change of combustion. The enthalpy changes will be determined by examining

heat and energy exchange in various situations and reactions. It is used for many things everyday including solid and liquid fuel testing, waste disposal, and explosive testing. In our lab, we will are applying calorimetry to determine the change in enthalpy of a weak acid-strong base reaction. My beginning question was: How can we apply Hess’ law and calorimetry to chemical equations to determine the heat exchanged in a reaction? We started by putting 100 mL of water into a coffee cup calorimeter (a

change or chemical phenomenon. BACKGROUND INFORMATION Standard enthalpy change of solution, ∆Hsolnø, is the enthalpy change when one mole of a substance dissolves in water to form a solution of infinite dilution under standard conditions.1 The standard enthalpy change can either be exothermic or endothermic. An exothermic reaction is a reaction where energy is released as a form of heat or light. This is usually denoted by a negative enthalpy change. The heat that is released in the reaction causes the

needed to determine a more accurate ΔT. Hess’s Law of Constant Heat Summation Not all enthalpy changes of reaction can be measured directly by using calorimetry and hence Hess’s Law can be used to determine the enthalpy changes that cannot be determined by direct measurements. Hess’s Law states that the enthalpy change of a reaction is independent of the pathways between the initial and final states, i.e. enthalpy change is a state function. An energy cycle or energy level diagram is used to determine

The purpose of this report is determine if sodium chloride is a viable option as a deicer on winter roads. To determine this, one must compare a multitude of factors. In this lab, the freezing point depression of water, enthalpy of dissolution, cost, and environmental impact will be discussed. A large factor in how effective a substance is as a deicer is it’s ability to decrease the freezing point of water. If the freezing point of water can be lowered, the outside temperature must be much colder

EXPERIMENTAL RATIONALE Hydrocarbons are organic molecules consisting of hydrogen and carbon only1 and can be classified as saturated or unsaturated. A saturated hydrocarbon has the maximum number of hydrogens that can be present, given the number of carbons in the compound, for example, acyclic alkanes. A hydrocarbon is unsaturated if a hydrogen can be added1. This is a result of a hydrogen in the molecule being replaced, for example, with a double or triple bond or ring structure. Three examples

out the respective enthalpies of the reactions. These two values completed the Table of Thermochemical Equations given and with respect to Hess’s Law, the heat of formation of solid NaCl was computed by adding the enthalpies in the table. Two Styrofoam cups and a thermometer through its lid served as the calorimeter where the reactions took place. Using the heat transfer equation, the enthalpy of the first reaction was computed to be -1.080 kJ/mol. On the other hand, the enthalpy of the second reaction