Many home barbeques are fueled with propane gas (C3H8).
What mass of carbon dioxide (in kg) is produced upon the complete
combustion of 18.9 L of propane (approximate contents of one
5-gallon tank)? Assume that the density of the liquid propane in
the tank is 0.621 g/mL. (Hint:
Begin by writing a balanced equation for the combustion
reaction.)
| m = ______________kg |
In: Chemistry
(a) Calculate the equilibrium constant for the following reaction at 25°C: Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) The standard cell potential of the corresponding voltaic cell is 0.030 V. (b) When equal volumes of 1.3 M solutions of Ag+ and Fe2+ are mixed, what is the equilibrium concentration of Fe2+? Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq)
In: Chemistry
When an oxygen molecule binds to hemoglobin, substantial evidence shows that the iron(II) changes from a low spin d6 state to a high spin state. How might this affect the size of the iron cation and its ability to fit in the square planar site in heme? Evidence shows that this size change is what initiates the cooperative interaction among the four heme sites in the protein.
In: Chemistry
A solution is 5 mM in each of the following ions:
| number | ion | Ksp of M(OH)2 |
| 1 | Mg2+ | 1.8e-11 |
| 2 | Cd2+ | 2.5e-14 |
| 3 | Co2+ | 1.6e-15 |
| 4 | Zn2+ | 4.4e-17 |
| 5 | Cu2+ | 2.2e-20 |
Indicate which of the metal ions would precipitate (or start to precipitate) at each of the following pH values. Indicate your answer with the number of the ion. Use 0 to indicate no precipitate. If more than one precipitate is expected, list the numbers in increasing order and separate them with commas. For example, 3,4,5 is ok but 5,4,3 is not.
pH = 5.00:
pH = 10.00:
What is the pH to the nearest 0.1 pH unit at which
Zn(OH)2 begins to precipitate?
pH =
In: Chemistry
Write the balanced reaction equation for the precipitation of
calcium carbonate from
potassium carbonate and calcium chloride. Don't forget to show the
states of matter.
In: Chemistry
For the reaction CuS(s) + H2(g) H2S(g) + Cu(s) ΔG°f (CuS) = −53.6 kJ/mol ΔG°f (H2S) = −33.6 kJ/mol ΔH°f (CuS) = −53.1 kJ/mol ΔH°f (H2S) = − 20.6 kJ/mol a. Calculate ΔG° and ΔH° at 298 K and 1 atm pressure. b. Will this reaction proceed spontaneously at 298 K and 1 atm pressure? c. Calculate the equilibrium constant for this reaction at 298 K. d. Calculate ΔS° at 298 K and 1 atm pressure. e. Calculate ΔG at 798 K and 1 atm pressure (assume ΔS° and ΔH° do not change with temperature). f. Calculate the equilibrium constant at 798 K and 1 atm pressure.
In: Chemistry
What feature is shared by formulas of colored compounds used as pigments?
In: Chemistry
Consider the solution formed from dissolving 11.20 ml of methylene chloride, CH2Cl2 (Mm=85.0g/mol, Density=1.33g/ml; non-electrolyte) into 102.8 ml of carbon tetrachloride, CCl4 (Mm=154g/mol, density=1.59g/ml; non-electrolyte). Determine the molality and molarity of the resulting solution assuming additive volumes.
In: Chemistry
I have no idea how to approach this problem:
Calculate the concentration of all species in a 0.145 M solution of H2CO3.
[H2CO3],
[HCO−3],
[CO2−3],
[H3O+],
[OH−]
Express your answer using two significant figures.
In: Chemistry
If a pure R isomer has a specific rotation of –146.0°, and a sample contains 80.0% of the R isomer and 20.0% of its enantiomer, what is the observed specific rotation of the mixture?
In: Chemistry
In: Chemistry
For my chemistry class we did a lab on "pKa determination of methyl red indicator", and for my lab report one of the questions asks to calculate the uncertainty (after calculating the average pka, etc.). Normally I would repeat the measurement 6 times to calculate the uncertainty, but due to limited starting materials I only did one complete measurement.
I am really confused on how to go about calculating the propagation of error for uncertainty for my calculations in this lab. (below are my results )
Table 3: Absorbance Values of the indicator solution in buffer solutions at different pH values.
|
Solutions |
Volume of 0.01M CH3COONa (cm3) |
Volume of 0.02M CH3COOH (cm3) |
Indicator Stock (cm3) |
Water (cm3) |
pH |
Absorba-nce at λHMR (at 470 nm) |
Absorbance at λMR (at 421 nm) |
|
1 (red) |
25.0 |
50.0 |
10.0 |
To make up to the mark |
4.67 |
1.961 |
1.230 |
|
2 (blue) |
25.0 |
25.0 |
10.0 |
To make up to the mark |
4.99 |
1.974 |
1.563 |
|
3 (green) |
25.0 |
10.0 |
10.0 |
To make up to the mark |
5.38 |
2.118 |
2.230 |
|
4 (orange) |
25.0 |
5.00 |
10.0 |
To make up to the mark |
5.68 |
1.982 |
2.166 |
AuHMR, λMR = 0.956
AuHMR, λHMR= 2.4654=2.47
AuMR, λHMR =1.8577= 1.86
AuMR, λMR= 2.3181= 2.32
Table 4: Computation of the pKa values of methyl red indicator using Handerson-Hesselbalch equation.
|
S. No. |
pH |
[MR] |
[HMR] |
[MR-]/[HMR] |
log[MR-]/[HMR] |
pKa= pH-log[MR-]/[HMR] |
|
1 |
4.67 |
0.293 |
1.60 |
0.513 |
-0.290 |
4.96 |
|
2 |
4.99 |
0.499 |
1.19 |
1.18 |
0.0703 |
4.92 |
|
3 |
5.38 |
0.882 |
4.53 |
4.53 |
0.656 |
4.72 |
|
4 |
5.68 |
0.875 |
6.04 |
6.04 |
0.781 |
4.90 |
|
Average value of pKa |
4.88 |
|||||
In: Chemistry
How will the equivalence point volume change if you titrate the two solutions (solution 1: a 10mL vinegar solution that has a concentration of 5%(w/v%))(solution 2: a 10-mL vinegar solution that has a concentration of 5% (w/v%) together with 30mL of water). What is the pH of the equivalence point of the two solutions if you titrate with 0.3M NaOH?
In: Chemistry
In: Chemistry
How does a neutralization reaction differ from buffer?
In: Chemistry