Answer:
ΔU=-369.2 kJ/mol.
Explanation:
We start from the equation:
Δ(H)=ΔU+Δ(PV), which is an extension of the well known relation: H=U+PV.
If Δ(PV) were calculated by ideal gas law,
PV=nRT
Δ(PV)=RTΔn.
Where Δn is the change of moles due to the reaction; but, this reaction does not give a moles change (Four moles of HCl produced from 4 moles of reactants), so Δ(PV)=0.
So, for this case, ΔH=ΔU.
The enthalpy of reaction given is for one mole of reactant, so the enthalpy of reaction for the reaction of interest must be multiplied by two:
ΔU=-369.2 kJ/mol.
Answer: The correct answer is: the water can transfer heat to your arm more quickly than the air.
Explanation: The heat is transferred from the air or water to your arm through convection. The convective heat transfer coefficient of water is higher than the air's, so, even though the temperature of boiling water is lower, the heat will be transferred more efficiently to the other surface, in this case, the hand.
The formula for chromium (III) phosphate trihydrate is CrPO4- 3H20. This compound if in the anhydrous state, exists as a green crystal whereas a hydrated form violet crystal. The formula for cobalt(II) phosphate octahydrate is Co3(PO4)2•8H2O.
<span>Filtration, if its a precipitate that means its insoluble. </span>
