Concept explainers
The radius of tungsten is 137 pm and the density is 19.3 g/cm3. Does elemental tungsten have a face-centered cubic structure or a body-centered cubic structure?
Interpretation:
The lattice structure of elemental tungsten has to be identified and justified.
Concept introduction:
In packing of atoms in a crystal structure, the atoms are imagined as spheres. The two major types of close packing of the spheres in the crystal are – hexagonal close packing and cubic close packing.
In body-centered cubic unit cell, each of the six corners is occupied by every single atom. Center of the cube is occupied by one atom.
Each atom in the corner is shared by eight unit cells and a single atom in the center of the cube remains unshared. Thus the number of atoms per unit cell in BCC unit cell is,
In face-centered cubic unit cell, each of the six corners is occupied by every single atom. Each face of the cube is occupied by one atom.
Each atom in the corner is shared by eight unit cells and each atom in the face is shared by two unit cells. Thus the number of atoms per unit cell in FCC unit cell is,
Answer to Problem 60E
Answer
The lattice structure of elemental tungsten is identified as cubic close packing with body-centered cubic unit cell.
Explanation of Solution
Explanation
Calculate the density of tungsten by assuming its structure as FCC.
The atomic radius of tungsten is given. The unit cell is assumed as that of face-centered cubic and its edge length is calculated. Accordingly, the volume, mass and density of FCC unit cell are calculated. The obtained value does not agree with the actual value of density of tungsten.
Calculate the density of tungsten by assuming its structure as BCC.
The atomic radius of tungsten is given. The unit cell is assumed as that of body-centered cubic and its edge length is calculated. Accordingly, the volume, mass and density of BCC unit cell are calculated. The obtained value agrees well with the actual value of density of tungsten.
Conclusion
The lattice structure of elemental tungsten is identified that of body-centered cubic since the density obtained by assuming the same agrees well with the actual value of density of tungsten.
Want to see more full solutions like this?
Chapter 10 Solutions
Chemistry (AP Edition)
- Draw the structure of the product of this reaction. H CH2CH3 Br H-... H H3C KOH E2 elimination product • Use the wedge/hash bond tools to indicate stereochemistry where it exists. • If there are alternative structures, draw the most stable one. • If no reaction occurs, draw the organic starting material. O + 98 // n ?arrow_forward4. a) Give a suitable rationale for the following cyclization, stating the type of process involved (e.g. 9-endo-dig), clearly showing the mechanistic details at each step. H CO₂Me 1) NaOMe 2) H3O® CO₂Mearrow_forward2. Platinum and other group 10 metals often act as solid phase hydrogenation catalysts for unsaturated hydrocarbons such as propylene, CH3CHCH2. In order for the reaction to be catalyzed the propylene molecules must first adsorb onto the surface. In order to completely cover the surface of a piece of platinum that has an area of 1.50 cm² with propylene, a total of 3.45 x 10¹7 molecules are needed. Determine the mass of the propylene molecules that have been absorbed onto the platinum surface.arrow_forward
- Chem 141, Dr. Haefner 2. (a) Many main group oxides form acidic solutions when added to water. For example solid tetraphosphorous decaoxide reacts with water to produce phosphoric acid. Write a balanced chemical equation for this reaction. (b) Calcium phosphate reacts with silicon dioxide and carbon graphite at elevated temperatures to produce white phosphorous (P4) as a gas along with calcium silicate (Silcate ion is SiO3²-) and carbon monoxide. Write a balanced chemical equation for this reaction.arrow_forwardProblem Set 4a Chem 1411. A latex balloon is filled with a total of carbon dioxide gas so that its volume reaches 1.352 L. The balloon whose weight was originally 0.753 g, now weighs 2.538 g. How many molecules of carbon dioxide have been added to the balloon?arrow_forwardQ18. 30 minutes left please help!!arrow_forward
- Please help with these drawings! I only have an hour left!arrow_forwardBriefly indicate and with examples the differences between metallic cluster and cage compound.arrow_forwardIndicate the correct answer.a) In boranes, the B-B bonds are the most reactive.b) The B-H-B bonds are the reactive centers in the B2H6 molecule.arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning