Chapter 11, Problem 95A

Interpretation Introduction

Interpretation : The percent yield needs to be calculated and given table needs to be completed.

Methanol Reaction Data
	CO(g)	CH3OH(l)
Mass	8.52g
Molar Mass	28.01 g/mol	32.05g/mol
Moles

Concept introduction : Wood alcohol is produced when CO reacts with hydrogen gas to produce methanol.

Percent yield is the efficiency of the chemical reaction.

Answer to Problem 95A

Methanol Reaction Data
	CO(g)	CH3OH(l)
Mass	8.5g	8.52
Molar Mass	28.01 g/mol	32.05g/mol
Moles	0.30	0.266

Percent yield: 87.65%

Explanation of Solution

Step 1: write balance chemical equation

$\begin{array}{l}CO+2H2\to CH3OH\\ 8.5g8.52g\end{array}$

Step 2: convert mass of reactant to moles

$\begin{array}{c}MolarmassofCO=28g/mole\\ Moles=\frac{Mass}{Molarmass}\\ MolesofCO=\frac{8.5}{28}=0.30moles\end{array}$

Step 3: Convert moles of reactant to moles of product using mole ratio

1 moles of CO produce = 1 moles of CH₃OH

0.30 moles of CO produce = 0.30 moles of CH₃OH

Step 4: Convert moles of product to mass (theoretical yield)

$\begin{array}{c}Molar\text{}massofCH3OH=32.04g/mole\\ Mass=Molarmass\times Moles\\ MassofCH3OH(Theoreticalyield)=32.04\times 0.30=9.72g\end{array}$

Actual yield = 8.52 g of CH₃OH

$\begin{array}{c}\text{Moles = }\frac{Mass}{Molarmass}\\ =\frac{8.52}{32.04}=0.266\end{array}$

$\begin{array}{c}PercentYield=\frac{Actualyield}{Theoreticalyield}\times 100\\ =\frac{8.52}{9.72}\times 100=87.65\%\end{array}$