10. Calculate q, w, ∆U, and ∆H when 50 g of O2(g) is heated at a constant pressure of 1 bar from 50 ºC to 200 ºC. Note: The constant volume heat capacity of O2 is 21.1 J mol-1 K-1.
In: Chemistry
1. Determine the pH of the buffer solution that is prepared by mixing 867 mL of 0.0403 M HEPES−H (C8H18N2O4S ) to 627 mL of 0.120 M HEPES (C8H17N2O4S− ). Assume the 5% approximation is valid. Report your answer to 2 decimal places.
2. Determine the pH of the HEPES−H/HEPES buffer solution after the addition of 21.2 mL of 2.89 M solution of hydrochloric acid to the existing buffer solution. Assume the 5% approximation is valid.
In: Chemistry
A pure gold ring and pure silver ring have a total mass of 15.4 g . The two rings are heated to 68.0 ∘C and dropped into a 13.0 mL of water at 21.5 ∘C. When equilibrium is reached, the temperature of the water is 23.7 ∘C.
Part A
What is the mass of gold ring? (Assume a density of 0.998 g/mL for water.)
Express your answer to two significant figures and include the appropriate units.
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|
|||
| mAu= |
Part B
What is the mass of silver ring? (Assume a density of 0.998 g/mL for water.)
Express your answer to two significant figures and include the appropriate units.
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| mAg= |
In: Chemistry
In: Chemistry
Top fuel dragsters and funny cars burn nitromethane as fuel
according to the following balanced combustion equation:
2CH3NO2(l)+3/2O2(g)→2CO2(g)+3H2O(l)+N2(g)2CH3NO2(l)+3/2O2(g)→2CO2(g)+3H2O(l)+N2(g)
The standard enthalpy of combustion for nitromethane is
−709.2kJmol−1−709.2kJmol−1.
Calculate the standard enthalpy of formation
ΔH∘fΔHf∘ for nitromethane.
ΔH∘fΔHf∘ ( kJmol−1kJmol−1 )
CO2(g)CO2(g) -393.5
H2O(l)H2O(l) -285.8
Express your answer using one decimal place.
In: Chemistry
Iodine clock reaction lab
2I-(aq) + S2O82-(aq)à I2(aq) + 2SO42- (aq)
Rate=k[I-]x[S2O82-]y
I need to calculate the initcial concentrations of I- and S2O8^2- then use that to calculate the reaction rate M/sec and the k value.
|
Run Number |
3% Starch |
0.012 Na2S2O3 mL |
0.20 M KI mL |
0.20 M KNO3 mL |
0.20 M (NH4)2SO4 mL |
0.20 M (NH4)2S2O8 mL |
Total= 2 mL |
Time sec |
|
1 |
2 drops |
0.200 |
0.800 |
0.200 |
0.400 |
0.400 |
2.00 |
35.75 |
|
2 |
2 drops |
0.200 |
0.400 |
0.600 |
0.400 |
0.400 |
2.00 |
109.72 |
|
3 |
2 drops |
0.200 |
0.200 |
0.800 |
0.400 |
0.400 |
2.00 |
218.65 |
|
4 |
2 drops |
0.200 |
0.400 |
0.600 |
0.00 |
0.800 |
2.00 |
33.31 |
|
5 |
2 drops |
0.200 |
0.400 |
0.600 |
0.600 |
0.200 |
2.00 |
219.18 |
In: Chemistry
Determine the pH of a solution that is 1.85% NaOH by mass. Assume that the solution has density of 1.01 g/mL.
In: Chemistry
Calculate how many milliliters of 0.663 M KOH should be added to 5.00 g of MOBS (see Table 8-2) to give a pH of 7.40. pKa=7.6. molecular weight=123.29
In: Chemistry
A- Calculate the pH at equilibrium point in the titration of 50mL of 0.1M HC2H3O2 with 0.16M NaoH. Ka=1.8^-5
B--Calculate the pH if 35mL of 0.025M HCl is added to 30mL of 0.030M NH3. Kb=1.8^-5
In: Chemistry
The excess Gibbs energy of solutions of methylcyclohexane (MCH)
and tetrahydrofuran (THF) at 303.15 K was found to fit the
expression
G E = RTx(1- x)[0.4857 – 0.1077(2x -1) + 0.0191(2x – 1)2 ]
where x is the molar fraction of the methylcyclohexane. Calculate the Gibbs energy of mixing when a mixture of 1.00 mol of MCH and 3.00 mol of THF is prepared.
In: Chemistry
Calculate the mass of carbon gas produced if 6.000g of K2CO3 reacts with 10.00ml of 2.00M HNO3 identify the limiting reagent as indicated a) if the amount of carbon dioxide collected is part a is 0.3542g, calculate the percent yield for the rection b) if the 0.3542g of carbon dioxide were collected at STP (0C and 1 atm), calculate th volumen of gas collected
In: Chemistry
Write the formula for the Bronsted-Lowry conjugate acid for each of the following bases.
NH2-
HSO4-
OH-
NH3
H2O
In: Chemistry
12) You need to reduce the radar cross-section of your company’s new plane. It already has been built according to principle of radar dispersion, so you must find a materials solution.?
Please explain in clear words. Thanks
In: Chemistry
8) Given the following equation, C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔG°rxn = -2074 kJ
Calculate ΔG°rxn for the following reaction.
21 CO2(g) + 28 H2O(g) → 7 C3H8(g) + 35 O2 g)
A) +14518 kJ B) -2074 kJ C) -14518 kJ D) -296 kJ E) +2074 kJ
22) Given the following equation, C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔG°rxn = -2074 kJ
Calculate ΔG°rxn for the following reaction.
7 C3H8(g) + 35 O2(g) → 21 CO2(g) + 28 H2O(g)
A) -14518 kJ B) +2074 kJ C) -2074 kJ D) -296 kJ E) +14518 kJ
29) Given the following equation, H2O(g) + CO(g) → H2(g) + CO2(g) ΔG°rxn = -28.6 kJ
Calculate ΔG°rxn for the following reaction.
5 H2(g) + 5 CO2(g) → 5 H2O(g) + 5 CO(g)
A) +143.0 kJ B) -28.6 kJ C) -143.0 kJ D) +5.72 kJ E) -5.72 kJ
In: Chemistry
What is the Ka for a weak acid, HA, if a .2 M HA solution has a pH of 4.0?
In: Chemistry