The aqueous solubility of \(\mathrm{CO}_{2}\) at \(20^{\circ} \mathrm{C}\) and 1.00 atm is equivalent to \(87.8 \mathrm{mL} \mathrm{CO}_{2}(\mathrm{g}),\) measured at STP, per \(100 \mathrm{mL}\) of water. What is the molarity of \(\mathrm{CO}_{2}\) in water that is at \(20^{\circ} \mathrm{C}\) and saturated with air at 1.00 atm? The volume percent of \(\mathrm{CO}_{2}\) in air is \(0.0360 \% .\) Assume that the volume of the water does not change when it becomes saturated with air.

Short Answer

Expert verified
The molarity of CO2 in water that is at \(20^{\circ} \mathrm{C}\) and saturated with air at 1.00 atm is approximately 14.1 µM.

Step by step solution

01

Determine the Moles of CO2

First, use the known solubility to calculate the moles of CO2. Given that the solubility is \(87.8 \mathrm{mL} \mathrm{CO}_{2}\) per \(100 \mathrm{mL}\) of water, this tells us that 87.8 mL of CO2 are dissolved in 100 mL of water under the conditions of the problem. At STP (Standard Temperature and Pressure), 1 mole of any gas occupies a volume of 22.4 L. So, you can convert the volume of CO2 into moles using this relationship: \[\frac{87.8 \mathrm{mL}\ \mathrm{CO}_2}{1} \times \frac{1 \mathrm{L}}{1000 \mathrm{mL}} \times \frac{1 \mathrm{mol}\ \mathrm{CO}_2}{22.4 \mathrm{L}} \approx 0.00392\ \mathrm{mol}\ \mathrm{CO}_2.\] This means there are approximately 0.00392 mol of CO2 in 100 mL of water.
02

Determine the Molarity of CO2

Next, calculate the molarity of CO2 using the moles calculated in the previous step and the volume of water. The molarity (M) is defined as the number of moles of solute divided by the volume of solution (in liters): \[M = \frac{n}{V}\] Substituting in the moles of CO2 (n) and the volume of water (V), you find: \[M = \frac{0.00392\ \mathrm{mol}\ \mathrm{CO}_2}{0.100\ \mathrm{L}} \approx 0.0392\ \mathrm{M}\] So, the molarity of CO2 in the water is approximately 0.0392 M.
03

Use Volume Percent to Calculate Final Molarity

The final step is to use the volume percent of CO2 in air to calculate the final molarity of CO2 in the water when it is saturated with air. The volume percent of CO2 in air is 0.0360%, which means that CO2 makes up 0.0360% of the volume of the air. Therefore, the final molarity is: \[0.0392\ \mathrm{M} \times 0.0360\% \approx 0.00001411\ \mathrm{M}\] or 14.1 µM.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free