Answer:
36.5 mol
Explanation:
The vapor pressure of a solution of a non volatile solute in water is given by Raoult´s law:
P H₂O = χ H₂O x P⁰ H₂O
where χ H₂O is the mole fraction of water in the solution and P⁰ H₂O
In the turn the mole fraction is given by
χ H₂O = mol H₂O / total # moles = mol H₂O /ntot
Thus
P H₂O = mole H₂O / n tot x P⁰ H₂0
now the mol of H₂O is equal n tot - 6 mol solute
Plugging the values given in the question and solving the resultant equation
19.8 torr = ( ntot - 6 ) x 23.7 torr / n tot
19.8 ntot = 23.7 ntot - 142.2
ntot = 36.5 ( rounded to 3 significant figures )
Answer:
25.53mL of 0.200 M FeCl₃ are needed to produce 0.345g of Fe₂S₃
Explanation:
Based on the reaction of the problem, 1 mole of Fe₂S₃ is produced from 2 moles of FeCl₃.
0.345g of Fe₂S₃ are (Molar mass: 207.9g/mol):
0.345g of Fe₂S₃ ₓ (1 mol / 207.9g) = <em>1.6595x10⁻³ moles Fe₂S₃</em>
Moles of Fe needed to produce these moles of Fe₂S₃ are:
1.6595x10⁻³ moles Fe₂S₃ ₓ ( 2 moles FeCl₃ / 1 mole Fe₂S₃) =
<em>3.3189x10⁻³ moles of FeCl₃</em>
As the percent yield of the reaction is 65.0%, the moles of FeCl₃ you need to add are:
3.3189x10⁻³ moles of FeCl₃ ₓ (100.0% / 65.0%) = <em>5.106x10⁻³ moles of FeCl₃</em>
A solution 0.200M contains 0.200 moles per L. Volume to obtain 5.106x10⁻³ moles is:
<em>5.106x10⁻³ moles of FeCl₃ ₓ ( 1L / 0.200mol) = 0.02553L = </em>
<h3>25.53mL of 0.200 M FeCl₃ are needed to produce 0.345g of Fe₂S₃</h3>
Answer:250 and your matthew sister
Answer:

Explanation:
We are given the mass of two reactants, so this is a limiting reactant problem.
We know that we will need mases, moles, and molar masses, so, let's assemble all the data in one place, with molar masses above the formulas and masses below them.
M_r: 17.03 32.00 18.02
4NH₃ + 5O₂ ⟶ 4NO + 6H₂O
m/g: 70.1 70.1
Step 1. Calculate the moles of each reactant

Step 2. Identify the limiting reactant
Calculate the moles of H₂O we can obtain from each reactant.
From NH₃:
The molar ratio of H₂O:NH₃ is 6:4.

From O₂:
The molar ratio of H₂O:O₂ is 6:5.

O₂ is the limiting reactant because it gives the smaller amount of H₂O.
Step 3. Calculate the theoretical yield.

I believe your answer is B.