Question

1. Write the molecular and net ionic equations for the reaction of aqueous hydrochloric acid and aqueous sodium hydroxide.

2. Write the equation used to calculate q

3. When 50.0 mL of 1.00 M hydrochloric acid and 50.0 mL of 1.00 M sodium hydroxide react, the temperature rises 6.7°C. Use the total solution volume, density of water, and specific heat of water to calculate DH in KJ/mol .

4. Does doubling the volumes of 0.10 M acid and 0.10 M base in a neutralization reaction double the amount of heat released? If yes, explain why

5. Does doubling the concentrations (but not the volumes) of acid and base in a neutralization reaction double the amount of heat released? If yes, explain why

6. What is the meaning of specific heat (s) and what would be the unit for it.

7. Styrofoam cup is an example for:

A-Open system

B-Closed system

C-Isolated system

D-Free system

True or false

1. Heat of reactions are always equal to DH

2. NaOH is hygroscopic substance, slowness in weighing and dissolution in water will result in an increase in the calculated heat of solution

3. In the heat of solution experiment changing NaOH to KOH will change the DH value

4. Heat of solution is always negative (exothermic)

Answer 1

The molecular equation is-

NaOH + HCl ---> NaCl + H2O

The ionic equation is-

Na+ + Cl- ---> NaCl

H+ + OH- ---> H2O

The equation used to calculate q-

qp = dH at constant Pressure

dH = m x c x dT Use this equation to find the value.

We are not provided with c value.

If you double the volume while keeping the concentration the same in both reactions you will indeed double the energy released. However, if you double the volume, but keep the same number of moles then the energy will not increase.  This is obvious. If you double the number of moles then you will double the energy.

- The concentrations of the reactants and the products. If the starting concentrations are more, then more reactions will occur, and therefore more energy will be released.

Specific heat capacity, it is the amount of energy that must be added, in the form of heat, to one unit of mass of the substance in order to cause an increase of one unit in its temperature. The SI unit of specific heat is joule per kelvin and kilogram, J/(K kg).

1. Styrofoam cup is an example for: A-Open system