Answer:
The half-life varies depending on the isotope.
Half-lives range from fractions of a second to billions of years.
The half-life of a particular isotope is constant.
Answer:
Mole fraction N₂ = 0.336
Explanation:
Mole fraction of a gas can be determined in order to know the partial pressure of the gas, and the total pressure, in the mixture.
Total pressure in the mixture: Sum of partial pressure from all the gases
Total pressure = 183 mmHg + 443 mmHg + 693 mmHg =1319 mmHg
Mole fraction N₂ = Partial pressure N₂ / Total pressure
443 mmHg / 1319 mmHg = 0.336
Remember that mole fraction does not carry units
Answer:
4.34.
Explanation:
<em>∵ pH = pKa + log [salt]/[Acid]</em>
∴ pH = - log(Ka) + log [salt]/[Acid]
∴ pH = - log(6.8 x 10⁻⁵) + log(0.75)/(0.50)
<em>∴ pH = 4.167 + 0.176 = 4.343 ≅ 4.34.</em>
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Answer:
No, it is not.
Explanation:
Most solutions do not behave ideally. Designating two volatile substances as A and B, we can consider the following two cases:
Case 1: If the intermolecular forces between A and B molecules are weaker than those between A molecules and between B molecules, then there is a greater tendency for these molecules to leave the solution than in the case of an ideal solution. Consequently, the vapor pressure of the solution is greater than the sum of the vapor pressures as predicted by Raoult’s law for the same concentration. This behavior gives rise to the positive deviation.
Case 2: If A molecules attract B molecules more strongly than they do their own kind, the vapor pressure of the solution is less than the sum of the vapor pressures as predicted by Raoult’s law. Here we have a negative deviation.
The benzene/toluene system is an exception, since that solution behaves ideally.
Answer: Option (b) is the correct answer.
Explanation:
The energy necessary to remove an electron from a gaseous atom or ion is known as ionization energy.
This means that smaller is the size of an atom more amount of energy has to be supplied to it in order to remove the valence electron. This is because in small atom or element there will be strong force of attraction between the nucleus and electrons.
So, high amount of energy has to be supplied to remove the valence electrons.
As electronic configuration of helium is
. So, due to completely filled valence shell it is more stable in nature.
As a result, we need to provide very high amount of energy to remove an electron from a helium atom.
Thus, we can conclude that out of the given options helium element would the first ionization energy of the atom be higher than that of the diatomic molecule.