Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 13: Problem 75

The \(\mathrm{pH}\) of a household ammonia cleaning solution is \(11.68\). How many grams of ammonia are needed in a 1.25-L solution to give the same pH?

Short Answer

Expert verified
Answer: Approximately 0.102 grams of ammonia are needed to prepare a 1.25 L solution with a pH of 11.68.

Step by step solution

01

Calculate the concentration of \(\mathrm{OH^-}\) ions from the given pH value

Using the relationship between pH, pOH, and the ion product constant for water (\(K_\mathrm{w}\)), we can find the \(\mathrm{OH^-}\) concentration. \(pH + pOH = 14\) To find the pOH, subtract the given pH value from 14: \(pOH = 14 - pH = 14 - 11.68 = 2.32\) Now, we can determine the concentration of \(\mathrm{OH^-}\): \([\mathrm{OH^{-}}] = 10^{-pOH} = 10^{-2.32} \approx 4.79 \times 10^{-3} \mathrm{M}\)
02

Find the concentration of ammonia \(\mathrm{NH_3}\)

The ammonia cleaning solution contains a weak base, ammonium hydroxide (\(\mathrm{NH_4OH}\)), that ionizes as follows: \(\mathrm{NH_4OH} \rightarrow \mathrm{NH_3} + \mathrm{OH^-}\) The concentration of \(\mathrm{NH_3}\) can be approximated as the concentration of \(\mathrm{OH^-}\), after considering the ionization reaction. So, \([\mathrm{NH_{3}}] \approx 4.79 \times 10^{-3} \mathrm{M}\)
03

Calculate the mass of ammonia required for 1.25 L of the solution

To find the mass of ammonia needed, we will use the molarity formula: mass = molarity \(\times\) volume \(\times\) molar mass \(\text{mass }(\mathrm{NH_3}) = [\mathrm{NH_3}] \times V \times \text{ Molar Mass }(\mathrm{NH_3})\) \(\text{mass }(\mathrm{NH_3}) = (4.79 \times 10^{-3}\mathrm{M})(1.25 \mathrm{L})(17.03 \frac{\mathrm{g}}{\mathrm{mol}})\) \(\text{mass }(\mathrm{NH_3}) \approx 0.102 \mathrm{g}\) Therefore, approximately 0.102 grams of ammonia are needed to prepare 1.25 L of a solution with a pH of 11.68.

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.

Start your free trial

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

Solution \(\mathrm{X}\) has a \(\mathrm{pH}\) of \(4.35 .\) Solution \(\mathrm{Y}\) has \(\left[\mathrm{OH}^{-}\right]\) ten times as large as solution \(\mathrm{X}\). Solution \(\mathrm{Z}\) has a pH \(4.0\) units higher than that of solution \(\mathrm{X}\). (a) Calculate the ratio of \(\left[\mathrm{H}^{+}\right]\) in solutions \(\mathrm{X}\) and \(\mathrm{Y}\) and solutions \(\mathrm{X}\) and \(\mathrm{Z}\). (b) What is the \(\mathrm{pH}\) of solutions \(\mathrm{Y}\) and \(\mathrm{Z}\) ? (c) Classify each solution as acidic, basic, or neutral.

State whether \(1 M\) solutions of the following salts in water would be acidic, basic, or neutral. (a) \(\mathrm{FeCl}_{3}\) (b) \(\mathrm{BaI}_{2}\) (c) \(\mathrm{NH}_{4} \mathrm{NO}_{2}\) (d) \(\mathrm{Na}_{2} \mathrm{HPO}_{4}\) (e) \(\mathrm{K}_{3} \mathrm{PO}_{4}\)

According to the Brønsted-Lowry theory, which of the following would you expect to act as an acid? Which as a base? (a) \(\mathrm{CHO}_{2}^{-}\) (b) \(\mathrm{NH}_{4}^{+}\) (c) \(\mathrm{HSO}_{3}^{-}\)

Using the Brønsted-Lowry model, write equations to show why the following species behave as weak acids in water. (a) \(\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{OH}^{+}\) (b) \(\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{3+}\) (c) \(\mathrm{H}_{2} \mathrm{~S}\) (d) \(\mathrm{HPO}_{4}^{2-}\) (e) \(\mathrm{HClO}_{2}\) (f) \(\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5}(\mathrm{OH})^{+}\)

Arrange the following \(0.1 M\) aqueous solutions in order of increasing pH (lowest to highest). \(\begin{array}{lllll}\mathrm{KOH}, & \mathrm{KF}_{3} & \mathrm{KCl}, & \mathrm{ZnCl}_{2}, & \mathrm{HCl}\end{array}\)
See all solutions

Recommended explanations on Chemistry Textbooks

Organic Chemistry

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Making Measurements

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

Read Explanation
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