Throughout the experiment, a lab coat was worn so that any spills do not cause damage to clothes or body. Do not touch the magnesium ribbon. A gas is beginning to form, only a little bit. Data All mass readings are given in units of grams g , and all temperature readings are given in degrees Celsius °C. You will use a Styrofoam cup nested in a beaker as a calorimeter, as shown in Figure 1. For the best estimation of maximum temperature reached, a magnified view of the intersection of horizontal line and y-axis is useful.
The alternate set of stepwise reactions that were followed in this experiment to arrive at the value for the enthalpy of formation of MgO s are as follows: 1. Every chemical and physical change is accompanied by a change in energy, which usually occurs in the form of heat. For classes with shorter attention spans, the final step of heating to constant mass could be omitted. Heat could have been lost to the We can use better insulators inside the surroundings, as the insulation may not calorimeter outside the beaker. Mass of Magnesium Oxide For part Y : For all trials, 0. Through experimentation it was found that the enthalpy of change for the combustion of magnesium is -593.
Building a perfect calorimeter is practically impossible but refinements to the materials used and design could help in building a more efficient calorimeter. Since the maximum temperature reached by the solution of 15cm3 water has been determined to be 34. Length of the Magnesium Strip Since the Magnesium roll was assumed to be of constant linear density, to obtain the same mass of magnesium each time, it was assumed that the length of the strip required would be the same. We can measure the heat change that occurs in the surroundings by monitoring temperature changes. I will measure the initial temperature of the acid using a measuring cylinder, and then I will add the calcium carbonate to the acid. Whichever point the two lines meet at can safely be assumed to be a good estimate of the maximum temperature reached and how much time had elapsed.
Analytical balances have an absolute uncertainty of ±0. I will carefully stir the mixture in the cup with the thermometer and then take the final temperature reading when the reaction is complete. It is an important aspect of thermochemistry, which is the study of energy changes during a chemical or physical reaction. The temperature of the acid was then measured using the thermometer and its reading noted. Why is usually the cup used in this experiment made of polystyrene? If light is involved a glow is seen, if heat is involved the temperature of the system will change lab manual page 35. Having done this for both elements, they should find the ratio between the two by dividing them both by the smallest number. They have additional uses beyond hyperacidity.
Each time the electronic balance was used, it was appropriately tarred to prevent any zero errors. Put the magnesium ribbon into the crucible and put the lid on. Conclusion: In this lab we were able to determine the heat of formation of MgO using a simply constructed calorimeter, which was found to be -618. The Enthalpy of Formation of Magnesium Carbonate By: Jessica Miller T. If we know the mass of magnesium at the start, and the mass of magnesium oxide produced at the end, we can work out the mass of oxygen which has been combined with the magnesium. Once 120 seconds were up, the calorimeter was emptied and cleaned so that another trial of the same experiment could be performed.
Random errors in this experiment were also quite large with the error due to uncertainty in the stopwatch only one being negligible enough. When pressure is constant, changes in energy q can be related to change in the enthalpy of reaction ΔHrxn. In the total of 4 trials, 92 thermometer readings have been taken. They could also calculate the increase in mass mass 3 - mass 2 , which corresponds to the mass of oxygen. For this concept, we use a device called a calorimeter, which is a device that creates an isolated system that enables the user to accurately measure the change in temperature, ΔT. In fact, only water and no gas was produced.
You may see the magnesium begin to flare up. The heat energy produced by such reactions can be measured using a calorimeter, a piece of equipment that can isolate the reaction in an insulated container. Calcium salts may be used as diet supplements to prevent osteoporosis. Using a data logger, the need of a student to keep track of time would be eliminated. The effectiveness of antacids is determined by its rate of reaction and residence time, which in turn are affected by various factors. There is no standard temperature.
However, non-absorbable antacids have numerous advantages. The enthalpy of reaction for each of these reactions can then be added together to give the enthalpy of reaction of the primary reaction formation of MgO, in this case. Introduction Chemical reactions require heat energy to complete, called an endothermic reaction, or produce heat energy, and thus called an exothermic reaction. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. The Constitution also states that the responsibility and duty of every citizen against the government and the nation.