Part B

Given: [tex]50.1 \, \text{g} \, \text{C}_2\text{H}_6\text{O}[/tex] in [tex]2.04 \, \text{L}[/tex] of solution

Express the molarity in moles per liter to three significant figures.



Answer :

Sure, here is a detailed, step-by-step solution to find the molarity of the solution:

### Step 1: Identify the given data
1. Mass of ethanol ([tex]\(C_2H_6O\)[/tex]): 50.1 grams
2. Volume of solution: 2.04 liters
3. Molar mass of ethanol ([tex]\(C_2H_6O\)[/tex]): 46.07 grams/mole

### Step 2: Calculate the number of moles of ethanol
To determine the number of moles of ethanol, use the formula:

[tex]\[ \text{{Number of moles}} = \frac{{\text{{mass}}}}{{\text{{molar mass}}}} \][/tex]

Plugging in the values:

[tex]\[ \text{{Number of moles}} = \frac{{50.1 \text{ grams}}}{{46.07 \text{ grams/mole}}} \approx 1.087 \text{ moles} \][/tex]

### Step 3: Calculate the molarity of the solution
Molarity ([tex]\(M\)[/tex]) is defined as the number of moles of solute per liter of solution. The formula for molarity is:

[tex]\[ M = \frac{{\text{{number of moles}}}}{{\text{{volume of solution in liters}}}} \][/tex]

Substituting in the values:

[tex]\[ M = \frac{{1.087 \text{ moles}}}{{2.04 \text{ liters}}} \approx 0.533 \enspace \text{moles/liter} \][/tex]

### Step 4: Express the molarity to three significant figures
From the calculations above, the molarity of the ethanol solution can be expressed as:

[tex]\[ M = 0.533 \enspace \text{moles per liter} \][/tex]

In summary, the molarity of the solution is [tex]\(0.533 \text{ M}\)[/tex], rounded to three significant figures.