Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 2: Q.25E (page 67)

The average atomic masses of some elements may vary, depending upon the sources of their ores. Naturally occurring, the boron consists of two isotopes with accurately known masses ( 10B, 10.0129 amu and 11B, 11.0931 amu). The actual atomic mass of boron can vary from 10.807 to 10.819, depending on whether the mineral source is from Turkey or the United States. Calculate the percent abundance leading to the two values of the average atomic masses of boron from these two countries.

Short Answer

Expert verified

From Turkey source:% of 10B = 26.5% and % 0f 11B = 73.5%

From United States (US) source:% of 10B = 25.37% and % of 11B = 74.63%

Step by step solution

01

– Determine the percentage abundance of Boron from Turkey Source

From Turkey source

Let thepercentage abundanceof 10B be X and 11B be 100-X.

B avg. mass = [(X)×10.0129amu] +[(100-X) × 11.0931amu)]/ 100

10.807 amu = [10.0129X + 1109.31 - 11.0931X]/ 100

1080.7 amu = 1109.31 – 1.0802X

X = (1109.31-1080.7)/ 1.0802 = 26.5%

So, 100-X= 100-26.5= 73.5%

02

– Determine the percentage abundance of Boron from US Source

From US source

Let thepercentage abundanceof 10B be X and 11B be 100-X.

B avg. mass = [(X)×10.0129amu] +[(100-X) × 11.0931amu)]/ 100

10.819 amu= [10.0129X + 1109.31 - 11.0931X]/ 100

1081.9 amu = 1109.31 – 1.0802X

X = (1109.31-1081.9)/ 1.0802 = 25.37%

So, 100-X = 100- 25.37 = 74.63%

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

Predict and test the behaviour of α particles fired at a Rutherford atom model.

(a) Predict the paths taken by α particles that are fired at atoms with a Rutherford atom model structure. Explain why you expect the α particles to take these paths.

(b) If α particles of higher energy than those in (a) are fired at Rutherford atoms, predict how their paths will differ from the lower-energy α particle paths. Explain your reasoning.

(c) Predict how the paths taken by the α particles will differ if they are fired at Rutherford atoms of elements other than gold. What factor do you expect to cause this difference in paths, and why?

(d) Now test your predictions from (a), (b), and (c).

Open the Rutherford Scattering simulation (http://openstaxcollege.org/l/16PhetScatter) and select the “Rutherford Atom” tab. Due to the scale of the simulation, it is best to start with a small nucleus, so select “20” for both protons and neutrons, “min” for energy, show traces, and then start firing α particles. Does this match your prediction from (a)? If not, explain why the actual path would be that shown in the simulation. Pause or reset, set energy to “max,” and start firing α particles. Does this match your prediction from (b)? If not, explain the effect of increased energy on the actual path as shown in the simulation. Pause or reset, select “40” for both protons and neutrons, “min” for energy, show traces, and fire away. Does this match your prediction from (c)? If not, explain why the actual path would be that shown in the simulation. Repeat this with larger numbers of protons and neutrons. What generalization can you make regarding the type of atom and effect on the path of α particles? Be clear and specific.

An element has the following natural abundance, and isotopic masses; 90.90% abundance with 19.99 amu, 0.26% abundance with 20.99 amu, and 8.82% abundance with 21.99 amu. Calculate the average atomic mass of this element.

Click on the site (http://openstaxcollege.org/l/16PhetAtomMass) and select the “Mix Isotopes” tab, hide the “Percent Composition” and “Average Atomic Mass” boxes, and then select the element boron.

(a) Write the symbols of the isotopes of boron that are shown as naturally occurring in significant amounts.

(b) Predict the relative amounts (percentages) of these boron isotopes found in nature. Explain the reasoning behind your choice.

(c) Add isotopes to the black box to make a mixture that matches your prediction in (b). You may drag isotopes fromtheir bins or click on “More” and then move the sliders to the appropriate amounts.

(d) Reveal the “Percent Composition” and “Average Atomic Mass” boxes. How well does your mixture match withyour prediction? If necessary, adjust the isotope amounts to match your prediction.

(e) Select “Nature’s” mix of isotopes and compare it to your prediction. How well does your prediction comparewith the naturally occurring mixture? Explain. If necessary, adjust your amounts to make them match “Nature’s”amounts as closely as possible.

Write a symbol for each of the following neutral isotopes. Include the atomic number and mass number for each.(a) the chalcogen with a mass number of \({\bf{125}}\)(b) the halogen whose longest-lived isotope is radioactive(c) the noble gas, used in lighting, with \({\bf{10}}\) electrons and \({\bf{10}}\) neutrons(d) the lightest alkali metal with three neutrons

Explain why the symbol for an atom of the element oxygen and the formula for a molecule of oxygen differ.

See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Read Explanation

The Earths Atmosphere

Read Explanation

Kinetics

Read Explanation

Making Measurements

Read Explanation

Chemistry Branches

Read Explanation

Nuclear 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