What molar ratio of sodium acetate to acetic acid should be used to prepare a buffer with pH = 4.5? Ka acetic acid = 1.8 x 10-5.

molar ratio: 0.58

Explanation:

This is a buffer problem. We would use the equation . Since we were given Ka and pH, we can find the ratio.

pKa=-log(Ka)

pKa=-log(1.8×10⁻⁵)

pKa=4.74

Now that we have pKa, we can plug in our values and find the molar ratio. Instead of writing base/acid, let's use x.

4.5=4.74+log(x)

-0.24=log(x)

10⁻⁰⁻²⁴=x

x=0.58

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.