Question

What is the enthalpy change of this reaction in kJ/mol?
NaOH (aq) + HCl (aq) --> NaCl (aq) + H2O (l)
50 cm3 of HCl acid was mixed with 50 cm3 of sodium hydroxide solution. Each solution contained 0.01 mol solute. The temp rise was 12 degrees Celsius. Assume the density of all solutions is 1.0 g/cm3. And use energy transferred (J) = mass of solution * 4.2 * change in temperature

Answer 1

Answer on Question #72292, Chemistry / Inorganic Chemistry

What is the enthalpy change of this reaction in kJ/mol?

$$\mathrm{NaOH} \, (\mathrm{aq}) + \mathrm{HCl} \, (\mathrm{aq}) \rightarrow \mathrm{NaCl} \, (\mathrm{aq}) + \mathrm{H_2O} \, (\mathrm{l})$$

50 cm³ of HCl acid was mixed with 50 cm³ of sodium hydroxide solution. Each solution contained 0.01 mol solute. The temp rise was 12 degrees Celsius. Assume the density of all solutions is 1.0 g/cm³. And use energy transferred (J) = mass of solution * 4.2 * change in temperature.

Solution

There is a required formula in the assignment, and to use it we need the mass of solution. The total volume of solution is

$$V = 50 + 50 = 100 \, (\mathrm{cm^3}).$$

As the density is 1.0 g/cm³, than the mass of solution is 100 g.

Find the energy transferred:

$$E = 100 \times 4.2 \times 12 = 5040 \, (\mathrm{J})$$

Found energy transfers after the reaction between 0.01 mols of initial reactants. Calculate the energy that is given off after the reaction between 1 moles of initial reactants:

$$E = \frac{5040}{0.01} = 504000 \, (\mathrm{J/mol}) \quad \text{or} \quad 504 \, (\mathrm{kJ/mol})$$

Answer

504(kJ/mol) is the enthalpy change of the reaction.

Answer provided by AssignmentExpert.com