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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.
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Chapter 21 Solutions
General Chemistry: Atoms First
- Question 4 Determine the rate order and rate constant for sucrose hydrolysis. Time (hours) [C6H12O6] 0 0.501 0.500 0.451 1.00 0.404 1.50 0.363 3.00 0.267 First-order, k = 0.210 hour 1 First-order, k = 0.0912 hour 1 O Second-order, k = 0.590 M1 hour 1 O Zero-order, k = 0.0770 M/hour O Zero-order, k = 0.4896 M/hour O Second-order, k = 1.93 M-1-hour 1 10 ptsarrow_forwardDetermine the rate order and rate constant for sucrose hydrolysis. Time (hours) [C6H12O6] 0 0.501 0.500 0.451 1.00 0.404 1.50 0.363 3.00 0.267arrow_forwardDraw the products of the reaction shown below. Use wedge and dash bonds to indicate stereochemistry. Ignore inorganic byproducts. OSO4 (cat) (CH3)3COOH Select to Draw ઘarrow_forward
- Calculate the reaction rate for selenious acid, H2SeO3, if 0.1150 M I-1 decreases to 0.0770 M in 12.0 minutes. H2SeO3(aq) + 6I-1(aq) + 4H+1(aq) ⟶ Se(s) + 2I3-1(aq) + 3H2O(l)arrow_forwardProblem 5-31 Which of the following objects are chiral? (a) A basketball (d) A golf club (b) A fork (c) A wine glass (e) A spiral staircase (f) A snowflake Problem 5-32 Which of the following compounds are chiral? Draw them, and label the chirality centers. (a) 2,4-Dimethylheptane (b) 5-Ethyl-3,3-dimethylheptane (c) cis-1,4-Dichlorocyclohexane Problem 5-33 Draw chiral molecules that meet the following descriptions: (a) A chloroalkane, C5H11Cl (c) An alkene, C6H12 (b) An alcohol, C6H140 (d) An alkane, C8H18 Problem 5-36 Erythronolide B is the biological precursor of erythromycin, a broad-spectrum antibiotic. How H3C CH3 many chirality centers does erythronolide B have? OH Identify them. H3C -CH3 OH Erythronolide B H3C. H3C. OH OH CH3arrow_forwardPLEASE HELP! URGENT! PLEASE RESPOND!arrow_forward
- 2. Propose a mechanism for this reaction. ہلی سے ملی N H (excess)arrow_forwardSteps and explanationn please.arrow_forwardProblem 5-48 Assign R or S configurations to the chirality centers in ascorbic acid (vitamin C). OH H OH HO CH2OH Ascorbic acid O H Problem 5-49 Assign R or S stereochemistry to the chirality centers in the following Newman projections: H Cl H CH3 H3C. OH H3C (a) H H H3C (b) CH3 H Problem 5-52 Draw the meso form of each of the following molecules, and indicate the plane of symmetry in each: OH OH (a) CH3CHCH2CH2CHCH3 CH3 H3C. -OH (c) H3C CH3 (b) Problem 5-66 Assign R or S configurations to the chiral centers in cephalexin, trade-named Keflex, the most widely prescribed antibiotic in the United States. H2N H IHH S Cephalexin N. CH3 CO₂Harrow_forward
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