Safety Precaution: Academic year. Hess’s Law and the Enthalpy of Combustion of Magnesium. NaOH→Na++OH- Safety precaution: Answer: 0000004072 00000 n Na++ OH-+H++Cl-→Na++Cl-+H2O Answer: (2) MgCl2+H2O→MgO+2HCl △H=42.16 kJ/mol Use a graduated cylinder and add 1.00 mol/L HCl to the calorimeter. 0000000976 00000 n Hydrochloric acid is corrosive. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. Data analyzing: Zilla Tofte. The concentration of HCl is very low, so the mixture of HCl and water is very similar to water. Recorded the mass of solid NaOH. CALORIMETRY AND HESS’S LAW: FINDING ΔH FOR THE COMBUSTION OF MAGNESIUM MATERIALS: 12 oz. Do you think that is a fair assumption? 0000004365 00000 n b e���_!��Zl�V�Q�O��eV;�-�P1���d)ĺG�N6�u������O9ι���t������D��+����H���HN:E���U>C���~p��I��i�Q�u���$yjK�\���G���%7�h��U���|���5җ��2*QW�˝�+�T�C��f���,#�ٸ���D ����9`���|sʍ�m����V�o�R��`W�$K|1S��:˭Y�S��S`�B7J,�㌄y'����W���٪�FC�o4��mM�djS����M�|�_/��e99JN� {�⺝͍���7^$�-�/�/kd��_���'�Ơ����{n�w ��G���U�4�V}Vm��LWݬ���{��T4���tV�8�bo�ά��1a� ��/�O���@K����,G���Y\ <1;��]|D���҈;����4�'B�B�SNU���y��E�c�Dz����B��W���hm�ƴ�� ~�Z��yA��|��*5eVedyi���`,w %PDF-1.4 %���� Bethany  Peter Jeschofnig, Ph.D. Comments. If time permits, obtain your teacher’s approval and carry out the investigation. thermochemistry and hess’s law prelab name_____ total_____/10 note: at this point you will answer all prelab questions in your carbon copy lab notebook. Disposed the reaction of solution. Thus we can use the same destiny and specific heat capacity as water to calculate HCl. Settled up the coffee-cup calorimeter. Write a step-by-step procedure for the investigation. University. Thermometer Be careful not let it touch your skin 0000007605 00000 n 0 The aim of the lab is to find out if the neutralization of NaOH and HCl is exothermic or endothermic, and if we can calculate the enthalpy change of the reaction c using Hess law. Use a graduated cylinder and add 1.00 mol/L H20 to the calorimeter. Posted on October 25, 2015 October 25, 2015 by bethany0xu. Part 3 Determine the △H of equation 3: Wear goggles during the experiment. 0000011059 00000 n 0000010477 00000 n Share. (�� {�Av�Ʋ� k�ʃ�]��`��>�8�� Lm����x���sS�pj�1��Q~}r�)����� 0000003248 00000 n 0000002602 00000 n This document is not meant to be a substitute for a formal laboratory report. Hess’s Law and the Enthalpy of Combustion of Magnesium, Mr. Celestine Used a graduated cylinder and added 100ml of 1.00 mol/L HCl to the calorimeter. The Lab Report. Part 2 Determine the △H of equation 2: U-*e�il���j��@��(\h*c���P�u1LѪ`}!�}W���)w(&�Z��svJ�֚bۊ��~(�Ȃ�!k�����m'�v=�K ��'��N�ƈ��"� �$����#��4E'Qp; Remember to put the proper sign (+ or -)in front of each △H value. ( Log Out /  0000003823 00000 n ( Log Out /  0000006226 00000 n Prediction: Answer: H��W�r�8�����Z4q�%U�0�d�I��&���Zom�$1! The independent variable is the amount of substance and the actual substance used in the reaction. reaction (3): q=mc△T=100*4.184*(44-24)=8368J=8.368kJ (CAUTION: HCl can burn your skin) Swirled the solution gently, recorded the temperature every 30s until reached the highest temperature Tf. Recorded the mass of sanded magnesium ribbon, m= 0.5g. at the start of lab you will hand in the carbon copy, which will contain answers to all Connect the Go-LinK to the USB connestor of your computer and connect the Stainless Steel Temperature Probe to the Go-LinK. We added these three equations all together algebraically, and then added these three △H values to find the △H of equation 1. Please sign in or register to post comments. 2. 0000003095 00000 n Design an investigation to verify Hess’s law, using the following equations. Scoopula Purpose: The purpose of this lab is verify Hess’s law by finding the enthalpies of the reactions; NaOH and HCl, NH 2 Cl and NaOH, and NH 3 and HCl. 2015,10,2. Grade 12 MgCl2+H2O+ Mg+2HCl+ H2+1/2O2→MgO+2HCl+MgCl2+H2+H2O Change ), You are commenting using your Twitter account. Sandpaper or emery paper 2) The amount heat released by the reaction are totally absorbed by the calorimeter. We added these three equations all together algebraically, and then added these three △H values to find the △H of equation 1. that should be addressed in a formal lab report. (3) Mg+2HCl→MgCl2+H2 △H=-406.85 kJ/mol It is fair because the main production of this reaction is water. Open the file “18 Hess's Law” from the Chemistry with Computers folder. �+��m\ J�dz�yZ�����n�>}���"�"�Q��?t��E��_�E�?��(�1����*�0��.���3�[email protected]���jeգ�]Q�Y�b+|^��O���`]��gFcmL�1I�=��6�2�W��В�)M��)6�ܾ����w?�akS9�]�\p���6>�o�If����l���o��~L:HB��ˬq�pVh:#K]2�3~+��������Fݓ6��Sr�<5�95挥�>|�P= Explain. startxref 0000001815 00000 n Aim: Use equations (2) MgO+2HCl→MgCl2+H2O ,(3) … (Improving: check the thermometer before the experiment). 0000004288 00000 n Aim: Explain how you used Hess’s law of heat summation to determine the △H of the combustion of magnesium. Mr. Celestine Grade 12 Bethany 2015,10,2. Conclusion: Added the MgO powder to the calorimeter containing the HCl. PURPOSE: The purpose of this experiment is to determine the enthalpy change for the combustion of magnesium: Mg (s) + ½ O2 (g) … Part 1 Determine △H of Equation (2). Disposed the reaction of solution. Start the Logger Pro program on your computer. Added the MgO powder to the calorimeter containing the HCl. Based on the accepted value, calculate your percentage error. 0000020375 00000 n 0000065421 00000 n %PDF-1.2 %���� Recorded the mass of 1.00 mol/L NaOH. MgO: n=m/M=0.8/(24.31+16)=0.02 Wear goggles during the experiment. 1.00 mol/L HCl. The thermometer has some problem, which made the data not so accurate. Be sure to include appropriated safety precautions. 0000005156 00000 n In what ways could you improve the procedure? Use equations (2) MgO+2HCl→MgCl2+H2O ,(3) Mg+2HCl→MgCl2+H2 and (4) H2+1/2O2→H2O+285.8kJ to determine the enthalpy change of equation (1) Mg+1/2O2→MgO. Procedure: NaOH+H++Cl-→Na++Cl-+H2O You should now see the screen shown here. Materials: Coffee-cup calorimeter Thermometer 100ml-graduated cylinder Scoopula Electronic balance MgO powder… Skip to content. MgO powder Recorded the initial temperature of the NaCl, Ti. 0000005611 00000 n 0000009041 00000 n 100ml-graduated cylinder 0000001676 00000 n q=-q= -8.368kJ, Convert the mass of MgO and Mg to moles. 44 0 obj <> endobj Recorded the initial temperature of the HCl, Ti=24°. Be careful not to inhale the magnesium oxide powder. 12 0 obj << /Length 13 0 R /Filter /FlateDecode >> stream The HCL and Mg are not fully reacted.