Part X — With Magnesium Strip 1. So as the magnesium was being carried from the measuring area to the workstation or while it was sitting on the counter top or being poured in, it could have reacted with the oxygen in the atmosphere and combusted. The container claimed to contain MgO with only trace amounts of impurities. From the figure, the value for the maximum temperature reached can be safely estimated to be 34. Use a graduated cylinder and add 1. Lattice A lattice is a part of bonding between metals. Swirled the solution gently, recorded the temperature every 30s until reached the highest temperature Tf.
Consequently, the heat value, or Q, would have been lower which also would have lead to a lower enthalpy value, like the one that was found. Often times, the reading was taken up to a second later. Building a perfect calorimeter is practically impossible but refinements to the materials used and design could help in building a more efficient calorimeter. This experiment had demonstrated the basic chemical reaction and the change in states between elements in order to form a stable ionic compound. By using this method, the need for graphical analysis is completely eliminated and with that the need to estimate the maximum temperature is also eliminated. Why theoretical value different from value obtained? Therefore the discrepancies in the experiment, however small, could have led to a lower value than expected which resulted in the low percent error. The exothermic reaction of combusting Magnesium produced a very bright light within the crucible due to the rapid heating of the Magnesium, where it quickly absorbs energy through ionisation.
By using this method, the need for graphical analysis is completely eliminated and with that the need to estimate the maximum temperature is also eliminated. It also demonstrated quantitative stoichiometric relationships between the number of moles, mass and molar mass in a chemical reaction. To determine the accuracy of the calculation we can determine the % error: As far as accuracy goes a percent error of 2. This can cause the equipment to crack and the shards may easily pierce the skin. There will be 3 variables in this experiment. The formula provides the simplest positive integer ratio of elements in a compound. The surface of the magnesium ribbon was thoroughly cleaned with steel wool and its appearance was recorded 8.
By firing the equipment under a blue Bunsen flame thoroughly, it became apparent that any moisture or volatile materials present are burnt off by 5minutes to reveal a clean crucible free of stains or moisture. When this temperature change is multiplied by the heat capacity, the amount of heat needed to raise the temperature of a body by one degree, we can measure the change in converting our initial components reactants to their respective products. Thermometer Different thermometers have different ranges and systematic and random errors. The quantitative stoichiometric relationships governing mass and amount is used in the following experiment regarding the combustion reaction of magnesium metal. State the result you obtained for the thermochemical equation that corresponds to chemical equation 1.
Since the maximum temperature reached by the solution of 15cm3 water has been determined to be 34. For Part Y, Trial 2 Graphical analysis similar to that used in Part Y, Trial 1 has been used to determine the maximum temperature reached in the duration of the reaction. To avoid errors, following precautions were taken: 1. Why the heat of neutralization has a negative sign? Retort stand, ring clamp, clay triangle 5. Only after investments in a better calorimeter and an analytical balance have been made, should one think to invest in a 15cm3 pipette.
The same ruler was used for all trials and 3cm of the Magnesium strip was cut each time using strong wire cutters. Controlled Variable Reason for controlling Method of Controlling Calorimeter Using different calorimeters can lead to different heat transfer rates and this is because different calorimeters are made up of different construction and specifications. The Magnesium was then added to the calorimeter and the lid of the calorimeter was closed as quickly as possible to prevent any heat losses. The molar mass is taken to be the relative atomic mass of an element which is the average mass of atoms present in any naturally occurring element relative to the mass of one atom of carbon-12 isotope taken as exactly 12 which gives formula weight sum of the atomic weights of the atomic species as given in the stated formula for the compound. Planning A: Refer to lab handout entitled, Heat of Reaction for the Formation of Magnesium Oxide. Introduction: Chemical reactions require heat energy to complete, called an endothermic reaction, or produce heat energy, and thus called an exothermic reaction.
We obtain the mole ratio as follows: Magnesium : Oxygen 2 : 1 With 2 moles of Magnesium reacting with 1 mole of Oxygen, this should suggest 2 moles of MgO after balancing the equation. Magnesium is reacted with oxygen from air in a contained crucible, and the masses before and after the oxidation is measured. Since the maximum temperature reached by the solution of 15cm3 water has been determined to be 40. Due to the heat loss from the calorimeter, the value for ΔT in each trial was understated because in each trial some amount of heat was lost which could have been used for generating a higher rise in temperature. A: Thomas Lab Partner: Rebekah Melanson Thursday Lab Room 106 Chemistry 1001-A Due Date: Thursday February 3rd 2011 Abstract The purpose of this experiment was to determine the enthalpy of formation of magnesium carbonate in a lab setting.
The reflex action may have caused a Two people can work simultaneously for small error in the temperature readings. As time went by, the solution was turning milky white. Put your gloves on and use care when handling it. The independent variable will be the mass of magnesium ribbon as different measurements will be taken and used for each trial. Almost smells like rotten eggs but not as strong. Therefore, the best way to deal with this problem would be to use freshly produced Magnesium strips for the experiment and after the experiment, store Magnesium under mineral oil to prevent any contact with Oxygen in the air so that it would be still be beneficial if the experiment were ever to be performed again in the future. For the best estimation of maximum temperature reached, a magnified view of the intersection of horizontal line and y-axis is useful.
The final error that may have occurred during the experiment was the loss of heat during the pouring stage. For 120 seconds, 24 readings were taken and noted in a pre-made data collection table. Turn off the gas and allow the apparatus to cool. If the surface of the magnesium ribbon were covered with a thin oxide coating prior to the reaction, the mass percent calculated of magnesium would be too high. To demonstrate with a simple example; The molecular formula of butane is C4H10, however as the ratio of carbon atoms to hydrogen atoms is 4:10; it can be reduced to the ratio of 2:5. Butane can now be represented in empirical formula as C2H5. Do not touch the magnesium ribbon.
These experiments led to the determination that the enthalpy of formation of magnesium carbonate is -1087. Then outline a plan for analyzing your data. Analytical balances have an absolute uncertainty of ±0. Used a graduated cylinder and added 100ml of 1. Quantity × Chemicals Purpose 60cm3 of 2. A lot of gas is forming. A lid was placed on top and through the hole, a thermometer was placed through it.