Answer:
the answeer is definitely silicon.
Assuming you meant a 0.7 mole sample of a gas, we can approximate this by assuming that the gas is acting ideally, and use the ideal gas law PV=nRT. Using the following values:
P = 1.2 Atm
V = 0.170 L
n = 0.7 mol
R = 0.08206 L-atm/mol-K
We can rewrite the equation as: PV/nR = T
Plug in our values:
(1.2 atm)(0.170 L)/(0.08206*0.7 moles) = approximately 3.55 Kelvin = T
Molar mass of N2H4 = 32 grams/mole
<span>3.95 grams of N2H4 = 3.95/32
= 0.123 moles </span>
<span>This will produce 0.123 moles of N2 </span>
<span>Now,
From the gas law equation. </span>
<span>P.V = n x R x T </span>
<span>P = 1 atm (given)
V = </span><span>0.123</span><span> x 0.082057 x 295 </span>
<span>V = 2.97 Liters </span>
<span>Theoretical yield = 2.97 Liters.
Actual yield = 0.750 Liters </span>
percentage yield = (0.75/2.97) x 100 %
= 25.25 %
PH3
Also known as phosphine
Choice B I think, because if the temperature decreases the particles move slower due to less kinetic energy, and thus won't collide as frequently.
