Granulated sugar dissolves faster than a sugar cube since it has a higher surface area. A sugar cube has a low surface which takes more time to dissolve.
Answer : The correct option is, (A) -x kJ/mol
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction is,

Now we have to determine the value of
for the following reaction i.e,

According to the Hess’s law, if we reverse the reaction then the sign of
change.
So, the value
for the reaction will be:


Hence, the value of
for the reaction is -x kJ/mole.
Answer:
What is the oxidation half reaction for iron?
The two elements involved, iron and chlorine, each change oxidation state; iron from +2 to +3, chlorine from 0 to -1. There are then effectively two half-reactions occurring. These changes can be represented in formulas by inserting appropriate electrons into each half-reaction: Fe2+ → Fe3+ + e.
Hope this helps..
D it is only physical and not chemical
Answer:
no of moles=mass in gm÷molar mass so let x be the mass in gm
4.5=x÷35.5×2
x=4.5×35.5×2 grams
x=319.5 gm
Explanation:
formula