Question

1. calculate the mass of 4.25 moles of h₂so₄₍ₗ₎.
2. how many grams of kcl₍ₛ₎ are there in 0.385 mol sample of kcl₍ₛ₎?
3. balance the following chemical equation

fe₍ₛ₎ + h₂s₍ₐq₎ → h₂₍g₎ + fe₂s₃₍ₛ₎
a) determine the amount of iron required to make 0.384mol of fe₂s₃₍s₎
b) determine the amount of hydrogen sulfide to produce 1.45 mol iron iii sulfide

Explanation:

Step1: Calculate molar mass of \(H_2SO_4\)

Molar mass of \(H = 1\space g/mol\), \(S=32\space g/mol\), \(O = 16\space g/mol\).
Molar mass of \(H_2SO_4=2\times1 + 32+4\times16=98\space g/mol\)

Step2: Calculate mass of \(H_2SO_4\)

Use formula \(m=n\times M\), where \(n = 4.25\space mol\), \(M = 98\space g/mol\)
\(m=4.25\times98 = 416.5\space g\)

Step3: Calculate molar mass of \(KCl\)

Molar mass of \(K = 39\space g/mol\), \(Cl=35.5\space g/mol\)
Molar mass of \(KCl=39 + 35.5=74.5\space g/mol\)

Step4: Calculate mass of \(KCl\)

Use formula \(m=n\times M\), where \(n = 0.385\space mol\), \(M = 74.5\space g/mol\)
\(m=0.385\times74.5=28.7825\space g\)

Step5: Balance the chemical equation

\(2Fe_{(s)}+3H_2S_{(aq)}\to3H_2{(g)} + Fe_2S_3{(s)}\)

Step6: Determine amount of iron (a)

From balanced equation, mole ratio \(Fe:Fe_2S_3 = 2:1\)
If \(n(Fe_2S_3)=0.384\space mol\), then \(n(Fe)=2\times0.384 = 0.768\space mol\)

Step7: Determine amount of hydrogen sulfide (b)

From balanced equation, mole ratio \(H_2S:Fe_2S_3=3:1\)
If \(n(Fe_2S_3) = 1.45\space mol\), then \(n(H_2S)=3\times1.45=4.35\space mol\)

Answer:

1. \(416.5\space g\)
2. \(28.7825\space g\)
3. Balanced equation: \(2Fe_{(s)}+3H_2S_{(aq)}\to3H_2{(g)} + Fe_2S_3{(s)}\)

a. \(0.768\space mol\)
b. \(4.35\space mol\)