Concept explainers
(a)
Interpretation:
The balanced reaction for the formation of the sol by hydrolysis of a stoichiometric mixture of aluminum ethoxide and tetraethoxysilane has to be calculated.
Concept introduction:
Balanced reaction is a
Steps in balancing the information
- Step 1: Write the unbalanced equation
- Step 2: Find the coefficient to balance the equation.
The coefficient should be reduced to the smallest whole number.
Sol-gel process:
- Sol-gel method: Metal alkoxide, (obtained from metal and alcohol) undergoes hydrolysis and yields metal hydroxide. These metal hydroxides are known as sol and they are fine particle. Further, metal hydroxides combined together to form oxygen bridges by eliminating water. Sol linked together through a three dimensional network of oxygen bridges in which is sol is converted to a material known as gel. By heating water and solvents are removed to get metal oxide
- Particles of the sol link together through a three dimensional network of oxygen bridges and the sol is converted to a more rigid gelatin like material called gel.
(b)
Interpretation:
The reaction that converts the sol to gel has to be explained.
Concept introduction:
Sol-gel process:
- Sol-gel method: Metal alkoxide, (obtained from metal and alcohol) undergoes hydrolysis and yields metal hydroxide. These metal hydroxides are known as sol and they are fine particle. Further, metal hydroxides combined together to form oxygen bridges by eliminating water. Sol linked together through a three dimensional network of oxygen bridges in which is sol is converted to a material known as gel. By heating water and solvents are removed to get metal oxide.
- Particles of the sol link together through a three dimensional network of oxygen bridges and the sol is converted to a more rigid gelatin like material called gel.
(c)
Interpretation:
The additional step requires that converts the gel to the ceramic has to be explained.
Concept introduction:
Sol-gel process:
- Sol-gel method: Metal alkoxide, (obtained from metal and alcohol) undergoes hydrolysis and yields metal hydroxide. These metal hydroxides are known as sol and they are fine particle. Further, metal hydroxides combined together to form oxygen bridges by eliminating water. Sol linked together through a three dimensional network of oxygen bridges in which is sol is converted to a material known as gel. By heating water and solvents are removed to get metal oxide.
- Particles of the sol link together through a three dimensional network of oxygen bridges and the sol is converted to a more rigid gelatin like material called gel.
Want to see the full answer?
Check out a sample textbook solutionChapter 21 Solutions
General Chemistry: Atoms First
- Silicon carbide (SiC) is made by the high-temperature reaction of silica sand (quartz) with coke; the byproduct is carbon monoxide.(a) Write a balanced chemical equation for this reaction.(b) Calculate the standard enthalpy change per mole of SiC produced.(c) Predict (qualitatively) the following physical properties of silicon carbide: conductivity, melting point, and hardness.arrow_forward(а) Give an example of zone refining of metals. (b) What is the role of cryolite in the metallurgy of aluminium?arrow_forwardWrite the role of the following: (i) Iodine in the refining of zirconium (ii) Silica in the extraction of copper from copper matte.arrow_forward
- What is the colour of FeSO4.7H2O crystals? How does this colour change upon heating? Give balanced chemical equation for the changes.arrow_forward(i) Name the method of refining of metals such as Germanium.(ii) In the extraction of Al, impure Al2O3 is dissolved in cone. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?(iii) What is the role of coke in the extraction of iron from its oxides?arrow_forward(1) Diamond and graphite are two minerals with identical chemical compositions, pure carbon (C). Diamond is the hardest of all minerals, and graphite is one of the softest. If their compositions are identical, why do they have such profound differences in physical properties? (2) silicon and oxygen together make up nearly 75 percent by weight of the Earth's crust. But silicate minerals make up more than 95 percent of the crust. Explain the apparent discrepancy. (3) If you were given a crystal of diamond and another of quartz, how would you tell which is diamond? (4) Would you expect minerais found on the Moon, Mars, or Venus to be different from those of the Earth's crust? Explain your answer. (5) Quartz is Si02. Why does no mineral exist with the composition Si03?arrow_forward
- (a) A hypothetical compound MB2 crystallises in the rutile lattice structure. (i) Draw the lattice structure of the unit cell MB2. (ii) Show by calculation that the stoichiometry of the formula is consistent with the structure. (iii) Determine the coordination number of the MB₂ unit cell.arrow_forwardBy making use of CFT in tetrahedral and octahedral geometries, predict whether nickel ferrite mineral (NiFe2O4) has a normal spinel or inverse spinel structure. Explain the structure of this mineral in detail.arrow_forwardDescribe the role of the following: (i) Si02 in the extraction of copper from copper matte. (ii) NaCN in froth floatation processarrow_forward
- Name the purification methods of cobalt(II) sulphate (CoSO4.7H2O).arrow_forward(a) What change occurs when AgCl is doped with CdCl2?(b) What type of semiconductor is produced when silicon is doped with boron?arrow_forwardExplain the role of each of the following in the extraction of metals from their ores :(i) CO in the extraction of nickel.(ii) Zinc in the extraction of silver.(iii) Silica in the extraction of copper.arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY