Question

In a constant‑pressure calorimeter, 50.0 mL50.0 mL of 0.330 M0.330 M Ba(OH)2Ba(OH)2 was added to 50.0 mL50.0 mL of 0.660 M0.660 M HCl.HCl. The reaction caused the temperature of the solution to rise from 23.66 ∘C23.66 ∘C to 28.16 ∘C.28.16 ∘C. If the solution has the same density and specific heat as water, what is heat absorbed by the solution? Assume that the total volume is the sum of the individual volumes. (And notice that the answer is in kJ).

Answer 1

0.075881 kJ

Step-by-step explanation:

The balanced equation for the reaction between

The enthalpy represents the energy that is either absorbed or released during a chemical reaction. It can be estimated experimentally using a calorimeter to measure the change in temperature after the reaction has occurred. The endpoint of the reaction is determined when there is no change in the temperature in the calorimeter.

With the data, we can use the next equation to estimate the heat (enthalpy) absorbed in this reaction.

`Q=m*Cp*delta T`

Where

Q is heat, m is mass of the reactants and Cp is the specific heat of the products and delta T is the change of temperature.

Mass of the reactants.

We know that molarity is

`M = (Moles)/(volume)`

So
`moles=M*volume`

We can estimate the moles for each reactant as:

`moles of Ba(OH)_(2) = 0.330 M * 0.05 L =0.0165 moles Ba(OH)_(2)`

`moles of HCl = 0.660 M * 0.05 L =0.033 moles HCl`

The molecular mass for each reactant is:

`HCl =36.4 (g)/(mol)`

`Ba(OH)_(2) = 171.34 (g)/(mol)`

The mass for each one is

`HCl = 36.4 (g)/(mol) * 0.033 moles HCl =1.2012 g`

`Ba(OH)_(2)  = 171.34 (g)/(mol) * 0.0165 moles Ba(OH)_(2)  =2.8271 g`

Total mass = 1.2012 g + 2.83 g = 4.0283 g

Cp is the one for the water

`4.186 (J)/(g * C)`

Delta T = 28.16 °C - 23.66 °C = 4.5 °C

Using the equation

`Q=m*Cp*delta T`

`Q= 4.0283 g * 4.186 (J)/(g * C )* 4.5 C =75.88 J`

The heat absorbed in this reaction is 75.88 J or 0.075881 kJ