PLease explain in detail the function of Lithium Fluoride and aluminium in the Lit/Al layer in organic solar cells. Please describe the organic chemistry structure in regards to the role.
In: Chemistry
How much heat is evolved in converting 1.00 mol of steam at 155.0 ∘C to ice at -45.0 ∘C? The heat capacity of steam is 2.01 J/(g⋅∘C) and of ice is 2.09 J/(g⋅∘C). Express your answer in units of kilojoules Assume the system is at atmospheric pressure.
Thanks all!!
In: Chemistry
The mass of a 270. mL beaker is 178 g when empty. Determine its mass when filled with the following substances.
(a) water (density 0.9970 g/cm3 at 20°C)
____ g
(b) alcohol (density 0.7893 g/cm3 at 20°C)
____ g
(c) mercury (density 13.546 g/cm3 at 20°C)
____ g
(d) Explain why mercury containing pollutants are usually found in
the mud at the bottom of a lake of stream.
-Mercury has a negative charge and is attracted to the positively charged particles on the lake or stream bed.
-Mercury containing pollutants do not float.
-Mercury is denser, and therefore sinks to the bottom of the lake or stream.
In: Chemistry
Part A
It takes 47.0 J to raise the temperature of an 9.50 g piece of unknown metal from 13.0∘C to 24.8 ∘C. What is the specific heat for the metal?
Express your answer with the appropriate units. Cs=
Parts B and C
The next two questions pertain to silver. They have nothing to do with unknown metal described in Part A.
Part B
The molar heat capacity of silver is 25.35 J/mol⋅∘C. How much energy would it take to raise the temperature of 9.50 g of silver by 19.5 ∘C?
Express your answer with the appropriate units. q=
Part C
What is the specific heat of silver?
Express your answer with the appropriate units.
In: Chemistry
You want to determine the percent of sulfate in an unknown sample of a hydrated metal sulfate with the formula My(SO4)x·nH2O. You dissolve 0.2888 g of your unknown in DI water and heat to near boiling. You react the dissolved unknown with a hot barium chloride solution and you collect the barium sulfate you make via gravity filtration. The filter paper weighed 0.597 g after a piece was torn off. The dry barium sulfate crystal and the filter paper weighed 0.910 g. Answer the following:
1. What is the molar mass of barium sulfate?
2. What is the molar mass of sulfate?
3. How many moles of sulfate were produced?
4. How many grams of sulfate were produced?
5. What is the percent sulfate?
I know the answer for the first two but im unsure of the next couple of questions. Thank you in advnadce :)
In: Chemistry
write a detailed mechanism for a) the hydrolysis of methyl salicylate in basic solution b) the acetylation of salicylic acid in acidic solution and c) the acetylation of vanillin in basic solution.
In: Chemistry
Calculate the pH of a solution made by adding 54 g of sodium acetate, NaCH3COO, to 12 g of acetic acid, CH3COOH, and dissolving in water to make 400. mL of solution.
In: Chemistry
A buffer that contains 0.592 M base, B, and 0.286 M of its conjugate acid, BH+, has a pH of 8.87. What is the pH after 0.0020 mol of HCl is added to 0.250 L of the solution?
In: Chemistry
1.)Describe the effect of increasing the concentration of the reactants on the rate of a reaction.
2.)The exponents in a rate law have no relationship to the coefficients in the overall balanced equation for the reaction. Give an example of a balanced equation and the rate law for a reaction that clearly demonstrates this.
3.)Compare the half-life equations for a first-order and a second-order reaction. For which reaction order is the value of the half-life independent of the reactant concentration??
In: Chemistry
| Na2SO4(mL) | BaCl2(mL) |
BaSO4(g) Actual Grams |
BaSO4(g) Actual Grams | |
| 8 | 2 | 0.58 | 0.54 | |
| 8 | 4 | 1.59 | 2.03 | |
| 8 | 6 | 2.45 | 2.39 | |
| 8 | 8 | 1.97 | 2.13 | |
| 8 | 10 | 1.61 | 2.08 | |
| 8 | 12 | 1.84 | 2.59 | |
| Can someone please help me in calculating the theoretical grams from this information. thanks. |
In: Chemistry
The two pKas of sulfurous acid (H2SO3) are 1.81 and 6.91, respectively. The predominant species at pH = 9 is: (Question from "Cracking the MCAT, 2010-2011 edition" by The Princeton Review)
|
1. H+ |
||
|
2. HSO3− |
||
|
3. SO32− |
||
|
4. H2SO3 |
In: Chemistry
Phosphine (PH3) decomposes into phosphorus and
molecular hydrogen:
4PH3(g) → P4(g) + 6H2(g)
Experiments show that this is a first-order reaction, with a rate
constant of 0.0173 s-1 at 650°C. Identify each of the
following statements about this reaction as true or false. (Use the
drop-down menu and select "True" or "False" for each. You must get
all 4 correct.)
True/False The mechanism for this reaction must involve
two or more elementary steps.
True/False The activation energy for the reaction cannot
be determined without additional data.
True/False The rate constant would be smaller than
0.0173 s-1 at 500°C.
True/False The rate-determining step for the reaction
could involve a bimolecular collision between two PH3
molecules.
In: Chemistry
Chemical Engineering Problem:
A vapor composed of 0.25 mole fraction ethanol and 0.75 mole fraction acetic acid at 120.0 mmHg (absolute), is in equilibrium with a liquid phase also composed of ethanol and acetic acid. Assume that the liquid is an ideal solution and apply Raoult\'s law to find the following. What is the temperature of the liquid?
What is the Temperature of the fluid? _____C
What are the mole fractions of the liquid phase?
XE=_____mol ethanol/mol
XA=_____mol acetic acid/mol
In: Chemistry
4 liter sealed container contains water vapour at 0.4 atm and 90°C. a) What is the dew point of the vapour? b) Determine the percentage of the vapour that will condense if the system is cooled to 50°C.
In: Chemistry
Part A
Determine the [H3O+] of a 0.250M solution of formic acid.
Express your answer using two significant figures.
[H3O+] = ???
Part B
Determine pH of this solution of formic acid.
Express your answer to two decimal places.
pH=???
In: Chemistry