In: Chemistry
A.) In yeast, ethanol is produced from glucose under anaerobic conditions. What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? A cell-free yeast extract is placed in a solution that contains 325 mmol glucose, 0.35 mmol ADP, 0.35 mmol Pi, 0.70 mmol ATP, 0.20 mmol NAD , and 0.20 mmol NADH. It is kept under anaerobic conditions. (answer in mmol)
B.) Under the same conditions, what is the theoretical minimum amount of glucose (in millimoles) required in the solution to form the maximum amount of ethanol? (answer in mmol)
In: Chemistry
What are two other methods to extract essential oils apart from steam distillation? Describe each.
In: Chemistry
Calculate the equilibrium compositions due to the decomposition
of 1 mole of nitrogen tetroxide at 25C and 1 bar in each of the
following cases.
N2O4(g) <==> 2NO2(g)
N2O4 : ΔHf (formation) = 9160 joules/mole and ΔGf
(formation) = 97540 joules/mole at 298 K
NO2 : ΔHf (formation) = 33180 joules/mole and ΔGf
(formation) = 51310 joules/mole at 298 K of
a.) Use the reaction equilibrium method with extent of reaction ξ,
and let the initial state be pure N2O4.
b.) Use the reaction equilibrium method with extent of reaction ξ,
and let the initial state be 1 mole inert Argon in addition to 1
mole of N2O4.
In: Chemistry
PCR;
4. A student is using the following PCR cycle conditions to amplify a 384 bp segment of DNA:
i) incubate at 95oC for 30 seconds;
ii) incubate at 53oC for 30 seconds;
iii) incubate at 72oC for 40 seconds.
(a) Describe what is happening during each step (i, ii, iii) of the PCR cycle.
(b) After gel electrophoresis of the PCR products, the students see three bands (212 bp, 288 bp, 866 bp) in addition to the desired 384 bp product. Which PCR step (i, ii, iii) should be modified, and how, to try and amplify only the desired 384 bp band? Explain.
In: Chemistry
Suppose that a student collects the following spectrophotometric data to determine the relative concentrations of HMR and MR in solution:
The abosorbance at 425 nm was measured to be 0.260 and at 520 nm was 0.880, the slopes corresponding to standard Beer's Law plots were as follows:
αIA = | 0.072 | αIB = | 0.306 |
αIIA = | 0.760 | αIIB = | 0.036 |
Using this data, calculate the ratio between the relative concentrations of MR- and HMR in this solution.
Using this data, calculate the ratio between the relative concentrations of MR- and HMR in this solution.
In: Chemistry
As background, an antacid contains an unknown number of milligrams (mg) of CaCO3 per 2.0 g tablet according to the label. (CaCO3: 100.09 g/mol). Based on the questions below, determine the mg of CaCO3 in the 2.0 g tablet. The reaction by which the antacid neutralizes HCl is 2 HCl(aq) + CaCO3(s) --> CaCl2(aq) + CO2(g) + H2O(l) Q1: How many moles of HCl are neutralized by one mole of CaCO3(s)? ___ mol Q2: 50.0 mL of 0.300 M HCl are added to an Erlenmeyer flask containing a 2.00 g antacid tablet. Calculate the moles of acid in the 50.0 mL of 0.300 M HCl? ___ mol Q3: A student fills her burette with NaOH to the 2.5 mL mark. She titrates her sample of the NaOH until she reaches the endpoint (i.e. all the acid has been neutralized by the NaOH). The volume marking on her burette - at the endpoint - is 52.5 mL. How many mL of NaOH did she use to reach the endpoint? Q4: Some of the 2.0 g of antacid neutralizes the HCl. However, there is excess acid, not neutralized by the antacid. To determine the excess moles of acid, a student used 50.00 mL of 0.100 M NaOH to titrate the excess acid. How many moles of excess acid are there? ___ mol HCl Q5: How many moles of HCl were neutralized by the 2.0 g antacid tablet? ___ mol Q6: How many mg of CaCO3 were in the original 2.00 g tablet? ___ mg
In: Chemistry
The stoichiometric relationship between the reactants and products of an aqueous reaction can be used to determine different kinds of information about a reaction, such as the volume of a given molarity reactant required to produce a certain amount of product.
Hydrochloric acid (HCl) reacts with sodium carbonate (Na2CO3), forming sodium chloride (NaCl), water (H2O), and carbon dioxide (CO2). This equation is balanced as written:
2HCl(aq)+Na2CO3(aq)→2NaCl(aq)+H2O(l)+CO2(g)
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a) What volume of 2.00 M HCl in liters is needed to react completely (with nothing left over) with 0.250 L of 0.300 M Na2CO3?
Express your answer numerically in liters.
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b) A 373-mL sample of unknown HCl solution reacts completely with Na2CO3 to form 19.1 g CO2. What was the concentration of the HCl solution?
Express the molar concentration numerically.
In: Chemistry
3. a) Calculate the pH of a sodium acetate-acetic acid
buffer solution (Ka= 1.78 x 10-5) in
which the concentration of both components is 1.0 M. What would be
the pH of the
solution if 1.5 mL of 0.50 M NaOH was added to 35.0 mL of the
buffer? How much
does the pH change?
b) If the same amount and concentration of NaOH was
added to 35.0 mL of pure water
(initial pH = 7), what would be the resulting pH change?
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When calculating multicomponent distillation, why is it best to list the components in order of decreasing volatility?
In: Chemistry
How much energy per mole is required to transfer acetic acid, a byproduct of ethanol metabolism from blood to urine. The relevant concentrations are 33.00 and 674.00 ppm respectively and you are running a fever at 39oC. State your answer in kJ/mol.
In: Chemistry
100 mL of a solution of compound “X” has the following properties:
–Molarity: 2M –MW of “X”: 500g/mole
–Density of compound “X”: 5.0g/cm3
What dilution factor would be required to make a solution of 1% (v/v) of “X”?
In: Chemistry
In: Chemistry
A solution is 0.010 M in each of Pb(NO3)2, Mn(NO3)2, and Zn(NO3)2. Solid NaOH is added until the pH of the solution is 8.50. Which of the following is true?
Pb(OH)2, Ksp= 1.4 x10^-20
Mn(OH)2, Ksp= 2.0 x 10^-13
Zn(OH)2, Ksp= 2.1 x10^-16
A) No precipitate will form.
B) Only Pb(OH)2 will precipitate.
C) Only Mn(OH)2 wil precipitate.
D) Only Zn(OH)2 and Pb(OH)2 will preipitate.
E) All three hydroxide will preipitate.
In: Chemistry
a)
What is the value of ∆H of the following chemical reaction?
NaOH(aq) + HCl(aq) -----> NaCl(aq) + H2O(l) + 55.216 kJ
b) Use the above equation to calculate the amount (in moles) of the water produced if you know that the mass of the solution was 100 g, the temperature change was 3oC, and the specific heat of the solution is 4.184 J/oC.g.
c) 54.6 kJ of heat is released when 1 mole of HCl reacts with 1 mole of NaOH to produce 1 mole of NaCl and 1 mole of H2O. Write a thermochemical equation for this reaction.
In: Chemistry