The only problem is that when I looked up the thermodynamic values I could not find MgCl2(aq) so would this just be 0? Steve O. Lv 7. The reaction you're using represents the formation of magnesium oxide from its elements in their most stable forms at standard state, 25^@"C" and "1 atm". Eqn 3 as is m is molality. While allowing Try looking for a table or appendix somewhere in your book to find the standard enthalpies of certain substances. 3 Answers. Ag 2 S(s)-40. I've concluded the answer is 0.02 moles of H2, but I'm doubting myself a lot because I don't understand the aspects of the, Please help me N2O5(g) + H2O(l) --> 2HNO3(l) delta H° = -76.2 kJ H2O(l) --> H2(g) + 1/2O2(g) delta H° = 286.0 kJ 1/2N2(g) + 3/2O2(g) + 1/2H2(g) --> HNO3(l) delta H° = -174.0 kJ Calculate delta H° for the reaction 2N2O5(g) -->, RXN #1: H2 (g) + O2 (g) --> H2O2 (l) ; delta-H =? x�b``�f``~��������ˀ �,l@����p���mÌP��;��x$>m�X. Using Hess's Law in 2 Questions Hi, can someone just check my work and see if I did something wrong? 0000004094 00000 n & ! 0000000916 00000 n AP Chemistry. Ag + (aq) 78. Use calorimetry to determine the I've concluded the answer is 0.02 moles of H2, but I'm doubting myself a lot because I don't understand the aspects of the, How many moles of magnesium chloride are formed when 55 mL of 0.70 M HCl is added to 42 mL of 1.204 g Mg(OH)2? © 2003-2020 Chegg Inc. All rights reserved. Al 2 O 3 (s)-1580. Then used calorimetry to determine the delta H2 %PDF-1.4 %���� MgO + 2HCl (aq) -> MgCl2+ H2O delta H = ? Given: H2 (g) = 1/2 O2 0000012234 00000 n degrees Celcius. m is molality. Delta H2 for eqn 2 is the delta H you measured but since you reversed the equation you want to change the sign. Privacy 1) MgO(s) +2HCI(aq)→ MgCl2(aq) +H2O(l) -411. 0000001278 00000 n JavaScript is disabled. 0000011878 00000 n Second equation I did for each reaction. For a better experience, please enable JavaScript in your browser before proceeding. 0000003119 00000 n The Enthalpy of MgO(s) + 2HCl(aq) Thread starter Raza; Start date Apr 8, 2006; Apr 8, 2006 #1 Raza. Calculate the delta H rxn for the following reaction: CH4(g)+4Cl2(g)-->CCl4(g)+4HCl Use the following reactions and given delta H's: 1) C(s)+2H2(g)-->CH4(g) delta H= -74.6 kJ 2) C(s)+2Cl2(g)-->CCl4(g) delta H= -95.7 kJ 3), Which of the following reactions are spontaneous (favorable)? mass of HCl +calorimter: 37.43 g, mass of Mg: 0.3 grams, The standard enthalpy change of formation, or DeltaH_f^@, of magnesium oxide will be -601.6 kJ/mol. RXN A: H2O2 (l) --> H2O (l) + 1/2 O2 (g); delta-H=-98.0 kJ/mol, which equation represents an oxidation-reduction reaction? Mg (s) = 2HCl (aq) = MgCl2 + H2 (g) / Data- mass of empty calorimter: 11.19 g, mass of HCl=25.14g, mass of HCl + calorimter:36.33g, mass of Mg: 0.171 g, temp of HCl: 24.9 degrees Celcius, temperature of HCl +Mg =51.6 degrees Celcius. Your Response. 1. © 2003-2020 Chegg Inc. All rights reserved. Theoretical value: delta H = -602 kJ, 2. However, we can apply Hess’s law to find the heat of formation for MgO by combining a series of reactions that are much safer and more suitable for a calorimetry experiment. Express the average rate as mol of Mg consumed per minute. : Mg(s) = 2HCl (aq) = MgCl2 Accurately weigh 0.3-0.4 g of magnesium oxide metal. 0000002630 00000 n The answers seems strange. View desktop site, "mgo + 2HCl rightarrow mgcl_2 + H_2O -(1) (s) (aq) (aq) (L) delta H = -411.016 KJ mg + 2HCl rightarrow mgc, 1) MgO(s) +2HCI(aq)→ MgCl2(aq) +H2O(l) -411. 56 0 obj <> endobj xref 56 31 0000000016 00000 n The specific heat is of MgCl2 is 0.750J/C*g. What is the value of delta(s)H for MgCl2? given the equation Mg +2HCL --> MgCL2+H2, how many moles of hydrochloric acid are needed to react with O.50 mol of magnesium ? Privacy To make these equations add up to the formation reaction of MgO, you will need to include the following: H2(g) + 1/2O2(l) delta H =-241.8 kJ