How will you determine the relationship between acid/base molarity and delta H?

Question

How will you determine the relationship between acid/base molarity and delta H? Write specific equations for the reactions that you will use in this determination (at least 3). What variables will you need to keep constant in this determination? The heat change value that you calculate from your experiments will be for the amount of material that you use in each reaction. How will you convert it to kJ/mol? By dividing by the stoichiometric coefficient. Write a procedure for determining the AH of solution for at least two different soluble salts. Choose the salts based on their solubility and their availability. Look up the delta H of solution for the salts you have chosen in the Handbook of Chemistry and Physics. Compare your experimental values to those found in the Handbook.

Explanation / Answer

Q4.

for a reaction of acid base, recall that

total Q = n*HRxn

and n = moles of acid/base

for the molarity = M = mol/V

so

mol = MV

relate via volume + Molarity

so

Qloss = Qgain

Hrxn = - Q / (M*V)

you need to keep constant specific heat, volume and specific heats, only temperature changes

Q5.

kJ/mol --> divide by 1000 J to kJ

Q6

For:

CaCl2 and Na2CO3, assume there is a heat of solution

so

Qsolution = mol of salt * Hsolution

so..

Qsolution = -Qsurrounding

let the surrounding be the water of claorimter

Qsurrounding = Q water + Qcalorimter

Qsurr = m*C*(Tf-Ti) + C*(Tf-Ti)

note that you should know Tinitial and final + Specific heat of water + Heat capacity of calorimtere

then:

HRxn = - Q surr / mol of salt

HRxn = -(m*C*(Tf-Ti) + C*(Tf-Ti)) / mol of salt

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