Answer:
A. 2 sig figs
Explanation:
In the number 0.0034, the zeros are called leading zeros. The only function of leading zeros is to fix the decimal point. Leading zeros are not counted as significant figures.
Answer:
From 4.0 moles of hydrogen 2.67 moles of ammonia are produced.
Explanation:
Given data:
Number of moles of hydrogen react = 4.0 mol
Number of moles of ammonia produced = ?
Solution:
Chemical equation:
N₂ + 3H₂ → 2NH₃
Now we will compare the moles of hydrogen and ammonia from balance chemical equation.
H₂ : NH₃
3 : 2
4 : 2/3×4 = 2.67 mol
From 4.0 moles of hydrogen 2.67 moles of ammonia are produced.
They can be converted, it's called nuclear transmutation.
Balanced equation:
2 Fe₂O₃ + 3 C → 4 Fe + 3 CO₂
number of moles of Fe₂O₃ = weight (g) / molar mass = (2.86 x 10⁴ g) / 159.69 g/mol = 179 moles
number of moles of C = (9.05 x 10³) / 12 = 754.16 moles
2 moles of Fe₂O₃ reacts with 3 moles of C
so 179 moles of Fe₂O₃ need 268.5 moles of C only
so carbon present in excess (754.16) and Fe₂O₃ is the limiting reactant so the number of moles used from Fe₂O₃ will be all the 179 moles
