Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
I think B
Hope this helps!
I think it’s :answer choice c
Answer: 43.3 l
Explanation:
1) Chemical equation:
2 Li(s) + 2 H₂O (l) → 2LiOH(aq) + H₂ (g)
2) Mole ratios:
2 mol Li : 2 mol H₂O : 2 mol LiOH : 1 mol H₂
3) Number of moles of Li that react
n = mass in grams / atomic mass = 24.6g / 6.941 g/mol = 3.54 moles
4) Yield
Proportion:
2 mol Li / 1 mol H₂ = 3.54 mol Li/ x
⇒ x = 3.54 mol Li × 1 mol H / 2 mol Li = 1.77 mol H₂
4) Ideal gas equation
PV = nRT ⇒ V = nRT / P
V = 1.77 mol × 0.0821 [atm×l / (mol×K)] × 301 K / 1.01 atm = 43.3 l
V = 43.3 l ← answer
