Part A
How many milliliters of 0.135 M HCl are needed to completely neutralize 46.0 mL of 0.101 M Ba(OH)2 solution?
Part B
How many milliliters of 0.126 M H2SO4 are needed to neutralize 0.180 g of NaOH?
Part C
If 55.6 mL of BaCl2 solution is needed to precipitate all the sulfate ion in a 758 mg sample of Na2SO4, what is the molarity of the solution?
Part D
If 42.1 mL of 0.204 M HCl solution is needed to neutralize a solution of Ca(OH)2, how many grams of Ca(OH)2 must be in the solution?
In: Chemistry
Experiment: Synthesis of Benzoin:
2.6g of thiamine hydrochloride in a flask was dissolved in 8ml of water, 30 ml of ethanol was added and cooled on an ice bath. 5ml of 3M Sodium Hydroxide was added. 15ml of benzaldehyde was added and heated for 1hr.
Question 1: how would the amount of of reagents change if the amount of benzaldehyde was reduced to 1 ml. with calculations please?
Question 2: What is the theoretical weight of the product with calculations please?
In: Chemistry
Concept questions: 1) Acetic acid is a weak acid. Why is a 2M solution of acetic acid less hazardous than a 2M solution of hydrochloric acid? 2) What species must be present in a buffer? Write a chemical reaction that explains how the buffer reacts with acid and then write a chemical reaction that shows how the buffer reacts with base. Wxplain how a buffer works.
In: Chemistry
H2 + I2 yields 2HI
At the start of the reaction 1 mole of I2 and 1 mole of H2 are put into a 10 liter container. There is no HI present. At the reaction temperature Keq is 64
What is the equilibrium concentrations for H2, I2 and HI?
In: Chemistry
Would cyclohexanone have 2 or 3 unique hydrogen for H-NMR?
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Why are cold solvents preferred during recrystallization and when is recrystallization selected vs other purification techniques?
In: Chemistry
In some materials the relationship between stress and strain during plastic deformation is given by σ = σy+ K(ε − εy) n where K and n are constants. What is the energy absorbed by the specimen during plastic deformation in a tensile test if the material yields at a strain of εy and fails at a strain of εf?
In: Chemistry
How do potassium sorbate and benzoate kill yeasts and molds? Would they impart an off-flavor in food?
In: Chemistry
Suppose you have an organic sample X that is somewhat soluble in water, even though it is
somewhat more soluble in dichloromethane or ether solvents. But if you do a single
extraction, you get only 60% of your material to transfer from the water to the organic layer.
a) How many “washes” would it take to extract over 90% of your organic material from
the water layer?
b) In this case, would it be better to extract with dichloromethane or with ether?
Assume you changed the solvent to ethyl acetate which has a KD for caffeine of 10. How much caffeine would you extract after three extractions? Show your work.
In: Chemistry
Discuss the microstructure of polymers based on the geometrical structure.
In: Chemistry
1-1Based on the Gibbs free energy of formation of substances listed in the table below, calculate EMF for the following cells:
(i) Zn | Zn2+ (1.0 M) || H+ (1.0 M) | O2 (1 atm) | Pt
(ii) Zn | Zn2+ (1.0 M) || Cu2+ (1.0 M) | Cu
(iii) Pt | H2(g) (1 atm) | H+ (1.0 M) || H+ (1.0 M) | O2 (1 atm) | Pt
_______________________________________________
Substances DGfo/ kJ mol-1 (298 K)
_______________________________________________
Zn2+(aq) -147.0
ZnO(s) -318.3
Mn2+(aq) -228.3
MnO4-(aq) -447.3
MnO2(s) -465.2
Mn2O3(s) -881.15
OH-(aq) -157.2
H2O(l) -237.1
Cu2+(aq) +65.52
Cu+(aq) +50.0
Fe3+(aq) -4.6
Fe2+(aq) -78.87
Cr3+(aq) -197.05
CrO42-(aq) -727.8
Cr2O72-(aq) -1301.2
Ce3+(aq) -672.0
Ce4+(aq) -533.06
Ag+(aq) +77.12
AgCl(s) -109.8
Cl-(aq) -131.3
_______________________________________________
In: Chemistry
Calculate delta H for the reaction H(g) + Br(g) = HBr(g), given the following information:
H2(g) + Br2(g) = 2HBr(g) delta H = -72 kJ
H2(g) = 2H(g) delta H = +436 kJ
Br2(g)= 2Br(g) delta H = +224 kJ
In: Chemistry
Which of the following reactions is unique to the process of glycolysis?
a. fructose-1,6-bisphosphate ====> glyceraldehyde-3-phosphate + dihydroxyacetone phosphate
b. 2-phosphoglycerate =====> 3-phosphoglycerate
c. glucose-6-phosphate =====> fructose-6-phosphate
d. phosphoenolpyruvate =====> pyruvate
In: Chemistry
In: Chemistry
Discuss the IMF of caffeine used in a TLC experiment with 1:1 Hexanes / Ethyl acetate as the solvent system and explain why the polarity of caffeine is high or low in this solvent?
In: Chemistry