1)Boron trichloride is prepared from the following reaction. 2B2O3 + 6Cl2 + 3C --> 4BCl3 + 3CO2 If 8.254g of B2O3 is mixed with 4.446g of Cl2 and 4.115g of C then answer the following questions.
A) What is the theoretical yield of boron trichloride in grams?
B)How much of each of the excess reagents with remain once the reaction is complete? (report in grams)
2)If the yield of the reaction in question 2 is known to be only 73.42%, how much of each of the three reagents would you need to obtain 10.000g of boron trichloride?
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A galvanic cell is constructed with a silver-silver chloride electrode, and a nickel strip immersed in a beaker containing 3.01 x 10-2 M solution of NiCl2. Determine the balanced cell reaction and calculate the potential of the cell. Enter in volts. (assume a temperature of 25
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Given that the following reaction begins at equilibrium, which
of the following describes the reaction immediately after a small
portion of
CO2(g)
is removed from the reaction container?
CO(g) +
H2O(g)
<---->
CO2(g)
+ H2(g)
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Q < Kc, reaction is spontaneous in reverse direction |
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Q < Kc, reaction is spontaneous in forward direction |
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Q > Kc, reaction is spontaneous in reverse direction |
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Q > Kc, reaction is spontaneous in forward direction |
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No effect 2. Use the initial concentration and initial rate data in the table
to determine the rate law for the reaction:
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the reaction of 7.26 g of carbon with excess O2 yeilds 8.20 g of CO2. What is the percent yeild of the reaction?
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Both solid LiH and CaH2 react with water to produce hydrogen gas and the corresponding hydroxide, LiOH or Ca(OH)2. A 0.850g sample of a mixture of LiH an CaH2 produces 1.200 liters of H2 at STP. What percentage of the starting mixture was LiH? (Give both mole percent and percent by weight)
In: Chemistry
How are the ?H values for reactions determined in the first place? The reactions are run in a calorimeter, which restricts and defines the surroundings so that thermal energy transfer to or from the surroundings (prompted by a change in temperature ?T) can be easily measured. Why measure the thermal energy change of the surroundings? So that we can then determine the thermal energy change of the system. Remember that thermal energy change, or heat transfer q , of the system and surroundings can be expressed as:
qsystem + qsurroundings = 0 (energy neither created nor destroyed)
qsystem = ? qsurroundings
One other thing: if your system is a tangible thing with a specific heat capacity, and your surroundings are tangible with a specific heat capacity, you can use the following:
qsystem = (m s ?T)system and qsurroundings = (m s ?T)surroundings
Substitute this into qsystem = ? qsurroundings to get:
(m s ?T)system = ?(m s ?T)surroundings
What mass of a hot (85.0
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Use the following for all problems involving water: Cice = 2.09 J/gºC Cwater = 4.184 J/gºC Csteam = 2.03 J/gºC ΔHfus = 6.01 kJ/mol ΔHvap = 40.7 kJ/mol Question 1 (1 point) How many grams of ice at 0ºC can be melted by 7.70 kJ of heat? grams (3 SF) Blank 1: Question 2 (1 point) How many kilojoules of heat are required to completely melt a 10.0 gram popsicle at 0ºC and raise the temperature to 22ºC? Assume the same properties as water. kJ (4 SF) Blank 1: Question 3 (1 point) 32.0 grams of ice at -28.0ºC melts into water at a temperature of 19.0ºC. How much energy is required to increase the temperature from -28.0ºC to 0ºC? J (3 SF) How much energy is required to melt the ice? kJ (3 SF) How much energy is required to increase the temperature from 0ºC to 19.0ºC? J (3 SF) What is the total energy required? KILOJOULES Blank 1: Blank 2: Blank 3: Blank 4: Question 4 (1 point) How much energy is required to raise the temperature of 18.0 grams of water at 27.7ºC to steam at 130ºC? KILOJOULES (3 SF) Blank 1: Question 5 (1 point) How much energy is required to raise the temperature of 1.99 grams of ice from -28.4ºC to steam at 111.2ºC? KILOJOULES Blank 1: Question 6 (1 point) How much energy is given off when 10.0 grams of oxygen gas is cooled from 25ºC to -232ºC? (Hint: Draw a heating curve for oxygen) KILOJOULES (3 SF) MP of O2 = -219ºC BP of O2 = -183ºC ΔHvap = 6.82 kJ/mol ΔHfus = 0.443 kJ/mol Cgas = 0.954 J/gºC Cliquid = 1.464 J/gºC Csolid = 3.256 J/gºC Blank 1:
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Αt 20°C, elemental iron is bcc, a = 2.866 Å. At 950 °C, Fe is ccp, a = 3.43 Å. At each temperature, calculate: a) The density of iron, b) The metallic radius of iron atoms. For Fe: A = 55.85 g/mol
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A sample of K(s) of mass 2.720 g undergoes combustion in a constant volume calorimeter at 298.15 K. The calorimeter constant is 1849 JK−1, and the measured temperature rise in the inner water bath containing 1439 g of water is 1.60 K.
a) Calculate ΔU∘f for K2O.
b) Calculate ΔH∘f for K2O.
the answer for ΔU∘f = -362 kJ⋅mol−1
and for ΔH∘f = -363 kJ⋅mol−1
how they got that answers ????
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It has been quite difficult if not impossible to produce nanoparticles from organic materials (especially for medicine) like Ibuprofen, aspirin, etc. since they aggregate at normal conditions. Propose a possible method of producing nano ibuprofen and nanoaspirin and explain why that is more feasible than other methods. Please be as much quantitative in your proposal as possible.
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A 3.900 g sample of a mixture of sodium hydrogen carbonate and potassium chloride is dissolved in 25.80 mL of 0.439 M H2SO4. Some acid remains after treatment of the sample. Write both the net ionic and the molecular equations for the complete reaction of sodium hydrogen carbonate with sulfuric acid. If 34.8 mL of 0.109 M NaOH were required to titrate the excess sulfuric acid, how many moles of sodium hydrogen carbonate were present in the original sample? What is the percent composition of the original sample?
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Consider the triprotic acid, H3A; pKa1: 2.91; pKa2: 8.2; pKa3: 13.3. Calculate the pH and the concentrations of H3A, H2A-, HA2-, A3-, OH- and H3O+ at equilibrium in a 0.10 M solution of the triprotic acid.
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Using data found in Appendix E of your textbook calculate the nonstandard emf for each of the following reactions if the concentration of each of the ions in these reactions is 0.0008 molar and everything else is standard (use 298 K for the temperature, R = 8.314 J/mol-K, and F = 96,485 C/mol):
(a) 1 Cl2(g) + 2 Cr2+(aq) --> 2 Cl-(aq) + 2 Cr3+(aq) E = _____ V
(b) 1 Fe3+(aq) + 1 Na(s) --> 1 Fe2+(aq) + 1 Na+(aq) E = _____ V
(c) 2 Li+(aq) + 2 I-(aq) --> 2 Li(s) + 1 I2(s) E = _____ V
(d) 1 Mn2+(aq) + 1 Pb(s) --> 1 Mn(s) + 1 Pb2+(aq) E = _____ V
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Aqueous silver nitrate reacts with aqueous lead (IV) acetate.
Calculate the grams of each product formed, starting witb 2.001g of
silver nitrate.
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