The Periodic Table

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5:04 AM

Q: Why might a prepared 1% solution of glucose take 2 hours to give maximum, stable reading on a glucometer?

I put 1.000g of glucose powder into a 1 L volumetric flask and filled the flask to the 1L line with room temperature distilled water. I then inverted several times for 10 minutes to mix until there was no visible glucose crystals left and tested the solution using an oxidase glucose strip. Even ...

15 hours later…

Curio

8:17 PM

Hi all! I totally disagree with the solution of this exercise.
<<Calculate reaction enthalpy for the following reaction:
Mg(s) + F2(g) -> MgF2(s)
knowing that mass of Mg(s) is 24.305g. The reaction emits Q=-46.22kJ>>
Now, according to the solution, ΔH = Q, BUT:
H = U + pV
ΔH = ΔU + VΔp + pΔV
ΔH = Q + W + VΔp + pΔV
ΔH = Q -pΔV + VΔp + pΔV
ΔH = Q + VΔp
How do I know that p is constant?

4 hours later…