My teacher said to make a Calorimeter lab report on this stuff.
What is the change in enthalpy for magnesium after the reaction with vinegar?
vinegar is 60ml
magnesium is 0.7g
T1 = ?
T2 = 31.8°C
Can someone HELP get started because I really don't know how to start it!
2 answers
I need help
I don't believe you have enough information to answer this qwuestion. You want to know the enthalpy for Mg AND you want to know the initial T. You CAN calculate dH for Mg from this but you have no data. You can look that information up in your text or ion Google. Call acetic acid HAc, then
Mg + 2HAc ==> Mg(Ac)2 + H2(g)
Look in your tables for dHo formation for HAc and Mg(Ac)2. Then
dHrxn = (n*dHo of products) - (n*dHo of reactants)
That will give you dHo or enthalpy for the reaction pf 1 mol Mg. which is 24.3 g. Convert that to 0.7 g Mg. Let's call that value q,
Then q = mass HAc x specific heat HAc solution x (Tfinal-Tinitial)
You know the value for q. Assuming the density of the HAc solution is the same as water then mass of the solution is 60 grams. Assuming the specific heat is the same as water solution that will be 4184 J/oC*g and you know Tfinal. Solve for Tinitial.
I don't know if this is what you are looking for. The problem I'm having is that you have two unknowns; i.e., you want enthalpy and you want Ti. I am showing yu how to calculate q but that may not be what you want.
Mg + 2HAc ==> Mg(Ac)2 + H2(g)
Look in your tables for dHo formation for HAc and Mg(Ac)2. Then
dHrxn = (n*dHo of products) - (n*dHo of reactants)
That will give you dHo or enthalpy for the reaction pf 1 mol Mg. which is 24.3 g. Convert that to 0.7 g Mg. Let's call that value q,
Then q = mass HAc x specific heat HAc solution x (Tfinal-Tinitial)
You know the value for q. Assuming the density of the HAc solution is the same as water then mass of the solution is 60 grams. Assuming the specific heat is the same as water solution that will be 4184 J/oC*g and you know Tfinal. Solve for Tinitial.
I don't know if this is what you are looking for. The problem I'm having is that you have two unknowns; i.e., you want enthalpy and you want Ti. I am showing yu how to calculate q but that may not be what you want.
2 answers