Energetics Aim: To measure the energy released from the complete combustion of a known mass of alcohol or paraffin wax, to heat water. Hypothesis: The combustion of alcohols is exothermic. In this experiment the energy is released from burning a known mass of alcohol in order to heat a known amount of water. A comparison of various alcohols and paraffin wax (methanol, ethanol, propanol, butanol, octanol and candle) as fuels can be made by calculating the quantity of energy transferred to the water. In this experiment, the amount of energy (heat) involved in a chemical change will be determined.
Therefore, according to Hess’s law, the heat of reaction of the one reaction should be equal to the sum of the heats of reaction for the other two. This concept is sometimes referred to as the additivity of heats of reaction. The primary objective of this experiment is to confirm this law. The reactions we will use in this experiment are: 18 - 1 Computer 18 You will use a Styrofoam cup in a beaker as a calorimeter, as shown in Figure 1. For purposes of this experiment, you may assume that the heat loss to the calorimeter and the surrounding air is negligible.
ceName___________________________________ Homework Chapter 8: Quantities in Chemical Reactions Please answer these questions on a scantron ;-) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The primary cause of increasing greenhouse gases is: A) the increased use of natural gas, petroleum and coal. B) the release of CO2 by decreasing solubility in the ocean. C) the production of CO2 by respiration.
Hypothesis I predict that if the concentration of Hydrochloric acid is increased by 20%, the rate of reaction will also increase by 20%. This is because more molecules of Hydrochloric acid will be present, meaning there will be more molecules to react with. For particles to react, they must collide with one another, but for a successful collision, there must be enough energy for them to react. This is known as activation energy. Activation energy is defined as “the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur”.
I. Introduction Calorimetry is a used to determine the amount of heat transfer in a chemical reaction. It can measure one of two things: the amount of heat that is absorbed (in an endothermic process) or the amount that is gained (in an exothermic process). To conclude the calorimetry of a substance, the equation below is used: Eq. 1 q= Cs x g x T Q represents heat.
Objectives: The purpose of this lab is to observe the reaction of crystal violet and sodium hydroxide by looking at the relationship between concentration and time elapsed of the crystal violet. CV+ + OH- CVOH To quantitatively observe this reaction of crystal violet, the rate law is used. The rate law tells us that the rate is equal to a rate constant (k) multiplied by the concentration of crystal violet to the power of its reaction order ([CV+]p) and the concentration of hydroxide to the power of its reaction order ([OH-]q). Rate = k[CV+]p[OH-]q To fully understand the rate law, concentrations of the substances must be looked at first. The concentration is measured in molarity.
The salts will be dissolved in distilled water by small quantities until the reaction reaches When ionic compounds dissolve in water, they either absorb energy from or release energy to the surroundings. If a chemical reaction absorbs heat from the surroundings, it is an endothermic reaction. If a solution releases heat to its surroundings, it is an exothermic reaction. The enthalpy of dissolution is the enthalpy change associated with the dissolution of a substance in a solvent at a constant pressure. The change in enthalpy relies on the concentration of the salt solution, because different concentrations will produce different enthalpies.
Any increase in the rate of reaction will cause an increase in the pressure of the oxygen. The first line of the graph (top) represents the normal rate of the reaction in a water solution of hydrogen peroxide and catalase. The second line represents the rate of reaction when acid is added to the solution and the third line represents the rate of reaction when a base is added to the solution. 1. What variable is plotted on the x-axis?
Different compounds boil at different temperatures because each has a different, characteristic vapor pressure: compounds with higher vapor pressures will boil at lower temperatures. Boiling points are usually measured by recording the boiling point (or boiling range) on a thermometer while performing a distillation. This method is used whenever there is enough of the compound to perform a distillation. The distillation method of
Hypothesis With increasing temperature of sodium thiosulphate the reaction rate will increase as well. Justification As the collision theory states for a chemical reaction to occur particles need to collide at a certain speed and angle. Increasing the temperature gives particles more energy, so they move faster. As they move faster more collisions happen, hence more successful collision, which increases the rate of the reaction1. Materials> Hydrochloric acid HCl(l)> Sodium triosulphate Na2S2O3(l)> 250 ml3 beaker> 50 ml3 conical flask> 2 x 25 ml3 measuring cylinder> Thermometer> Stop clock> Tea kettle> Blank card> Pen Variables Reaction time is the dependent variable, as it depends on the temperature of the solution.