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What was the mass of the solution after the addition of NH4Cl to the water? The density of water is 1g/mLA. 75 g B. 30 g C. 128 g D. 50 g What was the heat energy of the reaction between water and NH4Cl? To calculate the heat of the reaction you need to use the formula Q = mCpDeltaT where m is the mass of the solution (assume that the density is 1g/mL), Cp is the specific heat (assume 4.18 J/goC), and Delta T is the change in temperature from the initial and the final temperature. Choose the closest answer.A. 25 J B. 846 J C. 1556 J D. 4596 J What was the calorimeter’s heat absorption for the reaction between water and NH4Cl? To calculate the calorimeter’s heat absorption you must multiply the calorimeter constant (Ccal) by the Delta T from the reaction: Qcal = Ccal * Delta T Choose the closest answer.A. 578 J B. 2403 J C. 124 J D. 25 J Since the calorimeter absorbed some of the heat from the reaction between the water and NH4Cl, what is the corrected amount of heat energy from the reaction? To calculate the corrected heat energy, add the heat absorbed by the calorimeter to the heat that you calculated for the reaction (Q + Qcal). Choose the closest answer. A. 1680 J B. 982 J C. 438 J D. 29 J What is the enthalpy of the reaction (dH), per mole of NH4Cl. To calculate the molar enthalpy, take the corrected heat of reaction and divide it by the moles of NH4Cl present. Record your answer for use in a later question.  Choose the closest answer.A. 39 J/mol B. 450 J/mol C. 18,065 J/mol D. 9,553 J/mol What is the correct sign (+ or -) to place in front of the dH, molar enthalpy, for the reaction between water and NH4Cl?A. + dH because the reaction released heat into the surroundings B. +dH because the reaction absorbed heat from the surroundings C. -dH because the reaction released heat into the surroundings D. – dH because the reaction absorbed heat from the surroundings What type of reaction was the reaction between water and NH4Cl? A. volumetric B. exothermic C. endothermic D. bimodal Based on the molar enthalpies calculated for Experiment 2 and Experiment 3, you can now use Hess’s law to write out a series of reactions that will sum up to the reaction of the decomposition of ammonium chloride  NH4Cl(s) ? NH3(g) + HCl(g) In addition to the molar enthalpies from Experiment 2 and 3, you will also need to include the following reactions which account for the enthalpy change when HCl and NH3 change state: NH3 (g) -> NH3 (aq) (dH = -34,640 J/mol) HCl (g) -> HCl (aq) (dH = -75,140 J/mol) Be careful to use the positive or negative enthalpy values and to change the positive or negative sign if you change the direction of any reactions. Note that the final decomposition reaction has NH4Cl as a solid and the products are NH3 and HCl in the gaseous state. Choose the equation that shows the correct direction and sign for the enthalpy value for the reaction between HCl and NH3 in your series of reactions? A. NH4Cl(s) -> HCl(g) + NH3(aq)          -dH B. NH4Cl (aq) -> HCl(aq) + NH3 (aq)   +dH C. HCl(g) + NH3(g) -> NH4Cl(aq)         +dH D. HCl(aq) + NH3(aq) -> NH4Cl (s)       -dH Based on the molar enthalpies calculated for Experiment 2 and Experiment 3, you can now use Hess’s law to write out a series of reactions that will sum up to the reaction of the decomposition of ammonium chloride  NH4Cl(s) ? NH3(g) + HCl(g) In addition to the molar enthalpies from Experiment 2 and 3, you will also need to include the following reactions which account for the enthalpy change when HCl and NH3 change state: NH3 (g) -> NH3 (aq) (dH = -34,640 J/mol) HCl (g) -> HCl (aq) (dH = -75,140 J/mol) Be careful to use the positive or negative enthalpy values and to change the positive or negative sign if you change the direction of any reactions. Note that the final decomposition reaction has NH4Cl as a solid and the products are NH3 and HCl in the gaseous state. A. dH = -64,872 J B. dH = +179,965 J C. dH = -165,860 J D. dH = +83,700 J Experiment 3: Enthalpy of Dissolution of NH 4 Cl in Water 1. Take a new calorimeter from the Containers shelf and place it on the workbench. 2. Add 25 mL of water from the Materials shelf to the calorimeter. 3. Take a thermometer from the Instruments shelf and connect it to the calorimeter. Record the temperature inside the calorimeter. 25.1C 4. Add 5 g of ammonium chloride (NH 4 Cl) from the Materials shelf to the calorimeter. 5. Observe the temperature change in the calorimeter as the reaction proceeds. MAKE SURE that you record the highest temperature before the calorimeter begins to cool down. 9.1C temp 6. When you are finished, discard everything in the recycling bin. Remember to save your notes.