Zinc metal reacts with hydrochloric acid according to the balanced equation: zn(s) + 2 hcl(aq) ¡ zncl2(aq) + h2( g) when 0.103 g of zn(s) is combined with enough hcl to make 50.0 ml of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 °c to 23.7 °c. find ∆hrxn for this reaction as written. (use 1.0 g/ml for the

Volume of solution is 50 mL and density is 1 g/mL thus, mass can be calculated as follows:

m=V×d

Putting the values,

m= 50 mL× 1 g/mL=50 g

Now, heat released by reaction is equal to heat absorbed thus, heat released can be calculated as follows:

Here, SH is specific heat, m is mass and is change in temperature.

Specific heat of water is 4.18 J/g°C, putting the values,

Now, mass of zinc is 0.103 g and molar mass is 65.41 g/mol thus, number of moles of zinc can be calculated as:

Thus,

Putting the values,

Therefore, for the given reaction is

Zinc metal reacts with hydrochloric acid to form zinc chloride and release hydrogen gas. The equation is exothermic, therefore, the change in enthalpy will be negative. The equation is:

Given that,

Now, the heat released by reaction is equal to the heat absorbed. The heat evolved can be measured as:

Heat = m X SH X T,

where,

As water have specific heat of 4.18 J/g°C, substituting in the equation, it becomes:

Also, the mass of zinc is given that 0.103 g and molar mass is 65.41 g/mol. Then, number of moles in zinc will be:

Thus, enthalpy change will be:

Therefore, the = for the given equation.

To know more about enthalpy change, refer to the following link:

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