Answer:
C. ΔG is positive at low temperatures, but negative at high temperatures (and zero at some temperature).
Explanation:
Since we need to give energy in the form of heat to vaporize a liquid, the enthalpy is positive. In a gas, molecules are more separated than in a liquid, therefore the entropy is positive as well.
Considering the Gibbs free energy equation:
ΔG= ΔH - TΔS
+ +
When both the enthalpy and entropy are positive, the reaction proceeds spontaneously (ΔG is negative) at high temperatures. At low temperatures, the reaction is spontaneous in the reverse direction (ΔG is positive).
I got that pH=3.65 using the fact that Ka=[H⁺][A⁻]/[HA] at equilibrium. In the ice table, I stands for initial, C stands for change, and E stands for equilibrium.
I hope this helps. Let me know if anything is unclear.
He used a tube of mercury and marked the height of the mercury when placed in an ice bath as 0 degrees celsius, when he placed the tube in a boiling, he marked the height of mercury and called that 100 degrees celsius, he marked it linearly between 0-100 degrees celsius
The equation for the reaction between the calcium nitrate and chromium sulfate to form calcium sulfate and chromium(iii) nitrate is,
3Ca(NO3)2 + Cr2(SO4)3 --> 3CaSO4 + 2Cr(NO3)3
The balanced equation shows that for every 1 mole of chromium sulfate, there will be 3 moles of calcium nitrate. Therefore for this item, there will be 4.55 moles times 3 which is equal to 13.65.
