Question

QUESTION 1 0.5 points The weak acid, HX, is neutralized by sodium hydroxide as shown below: HX(aq) + NaOH(aq) + NaCN(aq) + H20(1). Suppose you carried out this reaction in a coffee cup calorimeter using 50.0 mL of 0.500 M HX and 50.0 mL of 0.500 M NaOH. If the temperature of the calorimeter increases by 1.36°C, what is the enthalpy of this neutralization reaction (in kJ/mol)? Assume the density of the solution is 1.00g/mL and that the specific heat is 4.184 J/g °C {Enter your value with the appropriate sign and value, but no units.} QUESTION 2 0.5 points Colorless gas nitric oxide gas, NO, can react with oxygen to form the brown gas nitrogen dioxide, NO2, as shown below: 2 NO(g) + O2(g) + 2 NO2(g). Suppose you wanted to carry out this reaction in the laboratory. You could filled one gas syringe with 100. mL of nitric oxide and another with 172. mL of oxygen gas. When you connected the syringes and mixed the gases, the reaction mixture changes to a brown color indicating the the reaction had occurred. If the syringes were maintained at constant temperature and pressure, what would be the expected volume of the reaction mixture after the reaction?

Answer both questions please and thank you!!!

Answer 1

1. The balanced chemical reaction is

        HX (aq) + NaOH(aq) ------> NaCN(aq) + H2O(l)

Total volume of the solution = 50 + 50 = 100 mL

Mass of the mixture = v*d = 100*1 = 100 gms

Heat evolved in the reaction (q) = msDT                                                       
                                                                                                    
                = 100 × 4.184*1.36 = 569.024 j
              
                = 0.569 kJ

Number of moles of HX = 50*0.500/1000 = 0.025 moles
                         
0.025 moles of 0.5 M HX liberates 0.569 kJ

1 mole 0f 0.5 M HX liberates

i.e. (0.569)/0.025

      = -22.8 kJ

2. The given balanced equation is

                            2NO(g)                 +                 O2(g) --------->            2NO2(g)                                stoichiometric moles     2.0 moles                           1.0 moles                     2.0 moles                                                  stoichiometric volumes   2 mL                                   1 mL                              2 mL       given volumes 100 mL 172 mL    - after the reaction    --    122 mL    100 mL

The total volume of the reaction mixture after the reaction is (100+122) = 222 mL