First we need to find the number of moles of hydrogen gas formed
Zn + 2HCl ---> ZnCl₂ + H₂
stoichiometry of Zn to H₂ is 1:1
the number of Zn moles reacted - 2.4 g / 65.4 g/mol = 0.0367 mol
assuming Zn to be the limiting reactant
number of Zn moles reacted = number of H₂ moles formed
therefore number of H₂ moles formed = 0.0367 mol
we can use ideal gas law equation to find the pressure
PV = nRT
P - pressure
V - Volume - 450 x 10⁻⁶ m³
n - number of moles - 0.0367 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 32 °C + 273 = 305 K
substituting these values in the equation
P x 450 x 10⁻⁶ m³ = 0.0367 mol x 8.314 Jmol⁻¹K⁻¹ x 305 K
P = 206.8 kPa
pressure is 206.8 kPa
Answer:
0.8749 grams of hydrogen gas was formed from the reaction.
Explanation:
P = Pressure of hydrogen gad= 744 Torr = 0.98 atm
(1 atm = 760 Torr)
V = Volume of hydrogen gas= 11 L
n = number of moles of hydrogen gas= ?
R = Gas constant = 0.0821 L.atm/mol.K
T = Temperature of vapor = 27.0 °C = 300.15 K
Putting values in above equation, we get:
Using an ideal gas equation:
n = 0.4374 moles
Mass of 0.4374 moles of hydrogen gas:
0.4374 mol × 2 g/mol = 0.8749 g
0.8749 grams of hydrogen gas was formed from the reaction.
Answer:
D) CN⁻
Explanation:
Hund's Rule of Maximum Multiplicity state that electrons go into degenerate orbitals of sub-levels (p,d, and f ) singly before pairing commences. Hund's rule is useful in determining the number of unpaired electrons in an atom. As such, it explains some magnetic properties of elements.
An element whose atoms or molecules contain unpaired electrons is paramagnetic. i.e., weakly attracted to substances in a magnetic field.
On the other hand, the element whose atoms or molecules are filled up with paired electrons is known as diamagnetic, i.e., not attracted by magnetic substances.
According to the molecular orbital theory, the diamagnetic molecule is CN⁻ because of the absence of unpaired electrons.
