s - orbitals have a spherical symmetry and the probability of finding an electron in an s orbital is equal for equal distance in x, y or z direction. i mean the probability of lets say an electron found at a distance 10 units from nuclues, its value will be same for x, y and z when u go 10 units distnace from nucleus in these directions. then the value at 5 units would be some value which also would be same for x,y and z.
Easier explanation is that if u place a ball, can u tell towards which axis it is oriented? no, its equally in all directions. So, non- directional.
However, if you have p- orbitals like dumb bells, a dumb bell can be oriented in three different directions, either x or y or z. see the pics.
Answer: 996 mmHg
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number of particles.
According to the ideal gas equation:
P = Pressure of the gas = ?
V= Volume of the gas = 25.5 L
T= Temperature of the gas = 13°C = (273+13) K = 286K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= 1.42
(760mmHg=1atm)
Thus pressure of this gas sample is 996 mm Hg.
Answer : The molecular weight of a substance is 157.3 g/mol
Explanation :
As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.
Mass of solute = 7 g
Mass of solution = 100 g
Mass of solvent = 100 - 7 = 93 g
Formula used :
where,
= change in freezing point
= temperature of pure water =
= temperature of solution =
= freezing point constant of water =
m = molality
Now put all the given values in this formula, we get
Therefore, the molecular weight of a substance is 157.3 g/mol