Answer: D.) 25.9%
Explanation:
Dinitrogen pentoxide chemical formular : N2O5
Calculating the molar mass of N2O5
Atomic mass of nitrogen(N) = 14
Atomic mass of oxygen(O) = 16
Therefore molar mass :
N2O5 = (2 × 14) + (5 × 16) = 28 + 80 = 108g/mol
Percentage amount of elements in N205:
NITROGEN (N) :
(Mass of nitrogen / molar mass of N2O5) × 100%
MASS OF NITROGEN = (N2) = 2 × 14 = 28
PERCENT OF NITROGEN : (28/108) × 100%
0.259259 × 100%
= 25.925%
= 25.9%
Answer:
No
Explanation:
The same amount of matter is present before and after chemical and physical changes. Matter cannot be created or destroyed
The molality of a solute is equal to the moles of solute per kg of solvent. We are given the mole fraction of I₂ in CH₂Cl₂ is <em>X</em> = 0.115. If we can an arbitrary sample of 1 mole of solution, we will have:
0.115 mol I₂
1 - 0.115 = 0.885 mol CH₂Cl₂
We need moles of solute, which we have, and must convert our moles of solvent to kg:
0.885 mol x 84.93 g/mol = 75.2 g CH₂Cl₂ x 1 kg/1000g = 0.0752 kg CH₂Cl₂
We can now calculate the molality:
m = 0.115 mol I₂/0.0752 kg CH₂Cl₂
m = 1.53 mol I₂/kg CH₂Cl₂
The molality of the iodine solution is 1.53.
Divide that my the molar mass which is 23 so 1.4087 g
I believe the answer is B!
