Answer:
(a) oxygen
(b) 154g (to 3sf)
(c) 79.9% (to 3sf)
Explanation:
mass (g) = moles × Mr/Ar
note: eqn means chemical equation
(a)
moles of P = 84.1 ÷ 30.973 = 2.7152 moles
moles of O2 = 85÷2(16) = 2.65625 moles
Assuming all the moles of P is used up,
moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)
moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)
therefore there is insufficient moles of O2 and the limiting reactant is oxygen.
(b)
moles of P2O5 produced
= 2/5 (according to eqn) × 2.7152
= 1.08608moles
mass of P2O5 produced
= 1.08608 × [ 2(30.973) + 5(16) ]
= 154.164g
= approx. 154g to 3 sig. fig.
(c)
% yield = actual/theoretical yield × 100%
= 123/154 × 100%
= 79.870%
= approx. 79.9% (to 3sf)
Answer:
lever Levers
Types of lever
Levers are all around us. Hammers, axes, tongs, knives, screwdrivers, wrenches, scissors—all these things contain levers.
Explanation:
C because I’m space there’s no gravity meaning things are weightless
Answer:
True
Explanation:
GIBBS FREE ENERGY (G) Gibbs free energy is a thermodynamic function It is a state function. G = H - TS At constant temperature At constant pressure and temperature An increase in S corresponds to a decrease in free energy
Constant free energy (G) P, T The important thing about free energy is that whenever the pressure and temperature are constant, we can determine the spontaneity of a process only in terms of the thermodynamic properties of the system G = H - TS The Free energy change is a measure of the change in the total entropy of a system and its environment at constant temperature and pressure. <u>Spontaneous processes at constant temperature and pressure are accompanied by a decrease in free energy</u>.
At constant temperature and pressure, the direction of spontaneous change is towards the lowest free energy. <u>The equilibrium state of a system corresponds to the lowest point of the free energy curve
</u>.
