Mass of H2C2O4 :
mm = 90.04 g/mol
number of moles : 0.0223 moles
m = n * mm
m = 0.0223 * 90.04
m = 2.007 g
hope this helps!.
Oxidation is when a substance gains oxygen molecules. For example when hydrogen reacts with oxygen it forms H₂O. The H₂ has been oxidised.
Not 100% sure if its right.
When an object covers equal distances in equal amounts of time, it is moving at a constant speed.
Answer : The internal energy change is, -506.3 kJ/mol
Explanation :
Formula used :

or,

where,
= change in enthalpy = 
= change in internal energy = ?
= change in moles
Change in moles = Number of moles of product side - Number of moles of reactant side
According to the reaction:
Change in moles = 0 - 2 = -2 mole
That means, value of
= 0
R = gas constant = 8.314 J/mol.K
T = temperature = 
Now put all the given values in the above formula, we get




Therefore, the internal energy change is -506.3 kJ/mol