-130KJ is the standard heat of formation of CuO.
Explanation:
The standard heat of formation or enthalpy change can be calculated by using the formula:
standard heat of formation of reaction = standard enthalpy of formation of product - sum of enthalpy of product formation
Data given:
Cu2O(s) ---> CuO(s) + Cu(s) ∆H° = 11.3 kJ
2 Cu2O(s) + O2(g) ---> 4 CuO(s) ∆H° = -287.9 kJ
CuO + Cu ⇒ Cu2O (-11.3 KJ) ( Formation of Cu2O)
When 1 mole Cu20 undergoes combustion 1/2 moles of oxygen is consumed.
Cu20 + 1/2 02 ⇒ 2CuO (I/2 of 238.7 KJ) or 119.35 KJ
So standard heat of formation of formation of Cu0 as:
Cu + 1/2 02 ⇒ CuO
putting the values in the equation
ΔHf = ΔH1 + ΔH2 (ΔH1 + ΔH2 enthalapy of reactants)
heat of formation = -11.3 + (-119.35)
= - 130.65kJ
-130.65 KJ is the heat of formation of CuO in the given reaction.
Answer:
The molecular formule for this unknow molecule is C2H4O2
Explanation:
The empirical formula is CH2O ( or better said CnH2nOn)
This means there are 3 elements in the formula of this molecule
⇒ Carbon (C) with a Molar mass of 12 g/mole
⇒ Hydrogen (H) with a Molar mass of 1 g/mole
⇒ Oxygen (O) with a Molar mass of 16 g/mole
We can also notice that the amount of hydrogen should 2x the amount of carbon ( also 2x the amount of oxygen).
The mass of the empirical formule = 12g/ mole + 2* 1 g/mole + 16 g/mole = 30 g/mole
To know what number is n in CnH2nOn we should divide the molecular mass by the empirical mass:
60 g/mole / 30g/mole = 2
this means n = 2
and this will give a molecular formule of C2H4O2
We can control this to calculate the molecular mass:
2*12 + 4* 1 + 2*16 = 24 + 4 + 32 = 60 g/mole
The molecular formule for this unknow molecule is C2H4O2
Answer 2: 1 mole = 6.03 x 1023 particles. One mole of any element has a mass in grams that is equal to its atomic number, and has exactly 6.02 x 1023 atoms - however because the atoms of each element have different sizes and weights, then the volume that each one occupies is different.
Credits to
https://scienceline.ucsb.edu/getkey.php?key=274
Answer:
oh it's easy
Explanation:
Take the hydrate
N
a
2
S
2
O
3
∙
5
H
2
O
. Are there ionic forces between the
N
a
+
and the
S
2
O
2
−
3
and ion-dipole forces between the cation/anions and the water?
Answer:
Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons
