Answer:
a) the final kilocalories per gram for food will be less because the mass was reduced
b)the final kilocalories per gram for food will be less since
c) the final kilocalories per gram for food will be less since the reaction will eventually go to completion
d) the final kilocalories per gram for food will be more.
Explanation:
a) the final kilocalories per gram for food will be less because the mass was reduced from 110.3 to 101.3g
b)the final kilocalories per gram for food will be less since some marshmallow fell off before the reaction
c) the final kilocalories per gram for food will be less since the reaction will eventually go to completion
d) the final kilocalories per gram for food will be more since the thermometer that got stuck will add to the value of final kilocalories per gram
I think one is Hydrochloric acid
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:
C6H6 has the strongest intermolecular force
i think
