Answer:
134.8 mmHg is the vapor pressure for solution
Explanation:
We must apply the colligative property of lowering vapor pressure, which formula is: P° - P' = P° . Xm
P° → Vapor pressure of pure solvent
P' → Vapor pressure of solution
Xm → Mole fraction for solute
Let's determine the moles of solute and solvent
17.5 g . 1 mol/180 g = 0.0972 moles
82 g . 1mol / 32 g = 2.56 moles
Total moles → moles of solute + moles of solvent → 2.56 + 0.0972 = 2.6572 moles
Xm → moles of solute / total moles = 0.0972 / 2.6572 = 0.0365
We replace the data in the formula
140 mmHg - P' = 140 mmHg . 0.0365
P' = - (140 mmHg . 0.0365 - 140mmHg)
P' = 134.8 mmHg
Well, when an atom attains a stable valence electron, it means that the outer electrons are complete and so cannot attain any more electrons. For the first shell, it is complete when it has 2 electrons, the second shell is complete when it has 8 electrons, all the other shells also have a particular number when complete. Anyway, i believe the answer is HYDROGEN because when HYDROGEN combines with another atom of HYDROGEN, the outer shell is completed. This is because HYDROGEN has only 1 electron. If the two HYDROGENS, which both have 1 electron combine, they make the electrons 2, which is complete for the first shell, HYDROGEN ends in the first shell. Since the electrons become 2, the shell is at stable valence. In all the other options, this happens;
NEON- It has 10 electrons, 2 in the first shell and 8 in the second. So the the shells are already complete, so it can't bond with any thing, which is completely against the question.
RADON- Radon has 86 electrons.
HELIUM- Helium has 2 electrons, so the shell is already full, and cannot bond, so it goes against the question. The question says BY BONDING.
So the answer is definitely 4) HYDROGEN
Hope i helped. Have a nice day, by the way, i'm very sure it's hydrogen.
Answer:
"nonmetal, nonmetal"
Explanation:
Oxygen is a non metal and Nitrogen is a non metal. It is 8th element of the periodic table. It is located in period 2 and group 16.
Nitrogen lies at the group 15 of the periodic table. Its atomic no is 7. Its valency is 2.
Hence, the correct option is (c) "nonmetal, nonmetal".
Answer:
K₂CO₃
Explanation:
Given parameters:
Number of moles of K = 0.104mol
Number of moles of C = 0.052mol
Number of moles of O = 0.156mol
Method
From the given parameters, to calculate the empirical formula of the elements K, C and O, we reduce the given moles to the simplest fraction.
Empirical formula is the simplest formula of a compound and it differs from the molecular formula which is the actual formula of a compound.
- Divide the given moles through by the smallest which is C, 0.052mol.
- Then approximate values obtained to the nearest whole number of multiply by a factor to give a whole number ratio.
- This is the empirical formula
Solution
Elements K C O
Number of moles 0.104 0.052 0.156
Dividing by the
smallest 0.104/0.052 0.052/0.052 0.156/0.052
2 1 3
The empirical formula is K₂CO₃
C. Formation of a new substance
