Chemistry

I have all of the answers except this one........... A photon interacts with a ground state electron in a hydrogen atom and is absorbed. The electron is ejected from the atom and exhibits a de Broglie wavelength of 5.908×10−10 m. Determine the frequency (in hz) of the interacting photon.

anyone want to help?

A solution is a mixture of a liquid (the -----) and a dissolved solid (the ----). When no more solid can dissolve, the solution is -----. The dissolved solid may then begin to reappera; we say it has -----.

Day after tomorrow is my exam. I have covered all most all the chapters in chemistry. But I am confused that how to revise all chapters just a day before exam. Please help.

I'll attach the question and my working in the below

For the chemical compound which is represented in vinegar together with water: What is the name and formula of this compound?

When copper metal reacts with concentrated nitric acid, SALT, WATER and GAS forms. What is the name of the gas?

Additional polymerisation - How does it work?

You need to cast an alloy of titanium (Ti) containing 46 at.% aluminium (Al). Using the information from your periodic table, estimate how much Ti and Al you will need to put in the crucible in order to cast a 100 g ingot of this alloy. b) By mistake, you added to the crucible 32.4 g of Ti and 67.6 g of Al. Work out the composition of your ingot in at.%.

I'm struggling with the calculation questions, know if you anyone could do a solution going through them?

Balance an symbol equation between methane and oxygen.

what is the balanced symbol equation for iron oxide add magnesium and how do i figure it out

Explain the interplay between enthalpy (H) and entropy (S) changes taking place during ligand binding. someone help please

What is the boiling point of Styrofoam (polystyrene)? NOT MELTING POINT

What are them types of flames

calcium oxide

The fHo of Ethanol (CH3CH2OH) (l)), Water (H2O (l)) and carbon Dioxide (CO2(g)) at 298K are respectively; -277.1 kJ mol-1, -285.8 kJ mol-1 and –393.5 kJ mol-1. Given that the latent heat of fusion of water is 6.02 kJ mol-1 and the average heat capacity of water is 75.3 J K-1 mol-1 how much ice (in grams) would be needed to put in a measure of whisky (25ml, 40% ethanol by volume) such that all the enthalpy of combustion of the ethanol is taken up raising the temperature of the ice to body temperature (35C). Density of ethanol = 0.789 g cm-3 (16 marks)

I have a diff problem .......Titanium (Ti) can be produced by the reaction of metallic sodium (Na) with titanium tetrachloride vapor (TiCl4). The byproduct of this reaction is sodium chloride (NaCl). Calculate the amount of titanium produced (in kg) when a reactor is charged with 73.0 kg of TiCl4 and 10.0 kg of Na.

can u discribe some properties of solids and liquids please

How is hydrogen used as a fuel? How is it produced? What are the advantages and disadvantages?

A catalyst consisting of palladium on an α-Al2O3 support, Pd/α-Al2O3, has been used for the oxidation of CO at room temperature:

Equation 1 CO(g) + ½O2(g) = CO2(g)

Under certain conditions, the oxidation reaction was found to involve competitive adsorption of the reactants with CO being non-dissociatively adsorbed and oxygen undergoing dual-site adsorption:

Equation 2 ka CO(g) + * ↔ CO(ad) Kd

Equation 3 ka’ O2(g) + 2* ↔ O(ad) + O(ad) kd’

The rate-limiting step is then a bimolecular reaction between CO(ad) and O(ad):

Equation 4 CO(ad) + O(ad) → CO (ad)

Carbon dioxide can be assume to be weakly adsorbed and, as a consequence, desorbs as quickly as it is formed.

(i) For the competitive adsorption of CO show that the following expression can be derived by equating the rates of adsorption and desorption of CO:

Equation 5 θCO = bCOpCO(1 – θCO – θO)

Where θCO and θO are the fractional surface coverages of CO and O, respectively. The quantity bCO (= ka/kd) is the adsorption coefficient for CO and pCO is the partial pressure of CO. (Hint In your working you should represent the total number of adsorption sites by N and provide expressions for both the rate of adsorption and the rate of desorption of CO.)

(ii) Equation 5 can be used in a more detailed analysis of the mechanism to derive the following two expressions:

Equation 6 θCO = (bCOpCO) / (1 + bCOpCO + (bO2pO2)1/2)

and

Equation 7 θO = θCO((bO2pO2)1/2 / bCOpCO)

where b02(= ka’ / kd’) and pO2 are, respectively, the adsorption coefficient and partial pressure of O2.

Given Equations 6 and 7, in conjunction with the information about the rate-limiting step at the start of this question, show that the theoretical rate equation takes the form:

Equation 8 r = (kθbCOpCO(bO2pO2)1/2) / {1 + bCOpCO + (bO2pO2)1/2}^2

(iii) The experimental rate equation for the CO oxidation reaction, under conditions for which the mechanism given in part (ii) is valid, takes the form:

Equation 9 r = (kR(pO2)1/2) / pCO

How can this result be rationalised in terms of the theoretical rate equation (Equation 8) that has been derived for the mechanism?

A catalyst consisting of palladium on an α-Al2O3 support, Pd/α-Al2O3, has been used for the oxidation of CO at room temperature:

Equation 1 CO(g) + ½O2(g) = CO2(g)

Under certain conditions, the oxidation reaction was found to involve competitive adsorption of the reactants with CO being non-dissociatively adsorbed and oxygen undergoing dual-site adsorption:

Equation 2 ka CO(g) + * ↔ CO(ad) kd

Equation 3 ka’ O2(g) + 2* ↔ O(ad) + O(ad) kd’

The rate-limiting step is then a bimolecular reaction between CO(ad) and O(ad):

Equation 4 CO(ad) + O(ad) → CO (ad)

Carbon dioxide can be assume to be weakly adsorbed and, as a consequence, desorbs as quickly as it is formed.

(i) For the competitive adsorption of CO show that the following expression can be derived by equating the rates of adsorption and desorption of CO:

Equation 5 θCO = bCOpCO(1 – θCO – θO)

Where θCO and θO are the fractional surface coverages of CO and O, respectively. The quantity bCO (= ka/kd) is the adsorption coefficient for CO and pCO is the partial pressure of CO. (Hint In your working you should represent the total number of adsorption sites by N and provide expressions for both the rate of adsorption and the rate of desorption of CO.)

(ii) Equation 5 can be used in a more detailed analysis of the mechanism to derive the following two expressions:

Equation 6 θCO = (bCOpCO) / (1 + bCOpCO + (bO2pO2)1/2)

and

Equation 7 θO = θCO((bO2pO2)1/2 / bCOpCO)

where b02(= ka’ / kd’) and pO2 are, respectively, the adsorption coefficient and partial pressure of O2.

Given Equations 6 and 7, in conjunction with the information about the rate-limiting step at the start of this question, show that the theoretical rate equation takes the form:

Equation 8 r = (kθbCOpCO(bO2pO2)1/2) / {1 + bCOpCO + (bO2pO2)1/2}^2

(iii) The experimental rate equation for the CO oxidation reaction, under conditions for which the mechanism given in part (ii) is valid, takes the form:

Equation 9 r = (kR(pO2)1/2) / pCO

How can this result be rationalised in terms of the theoretical rate equation (Equation 8) that has been derived for the mechanism?

Were i will write -um,-us , -ide etc. End of any chemical name

i need to be able to write the formula for each compund based on the name and ionic nomenclature as well so for instance CuSO4 and Iron(ll) oxide

What happens to stearic acid and paraffin wax at a molecular level and the velocity of molecules when it solidifies and melts?

I need help with my Chemistry AS A-level - looking for weekly tuition to cover the OCR A Exam board. Can anyone help?

Thanks, Bobby

I need additional help for my final year in A level in chemistry to reach my target grade. Can any one tutor Sundays ?

(a) A pressure vessel contains a large volume of CO2 gas at 10 atm pressure. A membrane composed of a poly(ether ketone) polymer with thickness 100 microns and net effective area of 100 cm2 covers a small perforated port in the container. The solubility of CO2 at 10 atm is 6.97 x 10-4 moles/cm3 at 35 C. The diffusivity of CO2 in the polymer is known to be 2.29 x 10-8 cm2/s at this temperature.

How long will it take for 0.001 moles of CO2 to leak from the container at steady-state? Assume that the amount of carbon dioxide in the surroundings is insignificant. Express your answer in hours.

(b) If the diffusivity is observed to double when the temperature is increased by 10 degrees C, what is the activation energy for diffusion? Express your answer in units of eV

Sulfur vapor is analyzed by photoelectron spectroscopy (PES). Measurements determine that photoelectrons associated with the 1st ionization energy of sulfur move with de Broglie wavelength λ=5.091 A˚. What is the maximum wavelength (in meters) of radiation capable of ionizing sulfur and producing this effect?

Seeking an experienced tutor, preferably with teaching experience and knowledge of both Chemistry and Biology (chemistry being the primary subject) A2 level AQA Board. Tutor needs in-depth knowledge, importantly to convey and teach the subject matter in an understandable, friendly and patient manner. From experience chemistry is particularly challenging with the absence of person to person interaction. Organic chemistry has been difficult to grasp. Also to help build and gain confidence and exam technique.

What is a covalent bond?

At school or revising at home I had no idea about cracking, what the process is or how it works, I nead help fully understanding. I am on higher tier for GCSE science. Thanks a lot.

Will Cu(OH)2 react with dilute sulfuric acid?

A sample of butane was collected over water. If this occurred at STP, what was the partial pressure of the butane?

Describe the occurrence of the neon and the processes involved in its extraction.

In order to prepare for this lab exercise one would be required to prepare 1.0 % (w/v) NaCl. Based on this lab exercise answer the questions below based on the diluents. a) How much diluent would an individual student require to complete this lab? Support the answer with relevant calculations.

b) One was instructed to prepare enough diluent for a class of 24 students. In determining the total amount of diluent needed each student would typically require slightly more volume. Assume that each student will take 25 % additional volume. Calculate the amount of diluent needed for a class of 24 students. Show using a labeled diagram how one would prepare the diluent.

can anyone help me with either one or both questions please!

Not really, though it would be helpful. If you love science, specifically chemistry, but aren't a maths fan it is possible to a) get a place at a good university b) do well on the course.

At degree level, chemistry is roughly divided into three areas, organic, inorganic and physical. The first of these only require GCSE level maths for small parts of the course. Physical chemistry also largely only requires this level, but some integration/differentiation is necessary, and certain modules are more maths heavy. So well over two thirds of your degree would be science only, and the final third would be science with a bit of maths!

That said, having maths A-level is still advantageous, and some courses require it. Universities such as the University of Bath offer top up maths courses so you can learn just the bits you need when you get there.

If you also love maths, then you will enjoy chemistry, but why not consider chemical engineering? This is largely about designing factories to make chemicals on a large scale, but also devices such as solar cells, deodorant cans, and football stadiums.

draw a table to show the differences between solids, liquids and gases. use these headings: keep its shape, keep its volume, flows,how dense it is

two identical charges each of 15g mass and negligible volume are both suspended from the same point by a non conduction weightless strings 1500mm in length. Find the magnitude of each charge is the angle between the strings is 5.

The answer to this question according to the back of the book is 0.11x10^-6C.

what is the relationship between volume and the amount of energy transferred as heat

You do a set of enzyme assays, plot a Lineweaver-Burk plot and estimate a Vmax reaction rate of 20 μmol.L-1.s-1 when the enzyme concentration is 10 ng.mL-1. Assuming that your enzyme is pure, that you have 20 mg of it and its Mr is 50,000:- - how many enzyme units do you have in total ? - what is the specific activity ? - what is the kcat ?

The last step in the biochemical pathway of glycolysis is:

Phosphoenolpyruvate + ADP Pyruvate + ATP

Its Standard Gibbs Free Energy, ΔGo, at 25C is -31.4 kJ.mol-1.

What is the equilibrium constant, Ke ?

(ΔGo = - RT ln{Ke}; R = Gas Constant = 8.3145 J.K-1.mol-1 ; T = absolute temperature)

If all reactants and products are at equal concentrations, in which direction will the reaction move naturally i.e. left or right ?

Estimate the 4th ionization energy of beryllium (Be). Express your answer in Joules (J/atom).

The gas-phase reaction between trichloromethane, CHCl3, and chlorine, Cl2, has time-independent stoichiometry and can be represented as follows:

Equation 1 CHCl3(g) + Cl2(g) = CCl4(g) + HCl(g)

Under certain experimental conditions, the experimental rate equation was found to be:

Equation 2 J = kR[CHCl3][Cl2]^1/2

A three-step mechanism has been proposed for Reaction 1:

Equation 3 k1 Cl2 ↔ 2Cl• k-1

Equation 4 k2 CHCl3 + Cl• → HCl + CCl3•

Equation 5 k3 CCl3 + Cl• → CCl4

(i) Explain why the form of the experimental rate equation indicates that Reaction 1 cannot be an elementary reaction.

(ii) With reference to the three-step mechanism (Equations 3–5 ), and assuming that the second step (Equation 4) is rate-limiting, derive the chemical rate equation for this mechanism and then compare it with the experimental rate equation given in Equation 2.

(iii)The activation energy for the forward reaction, Ef , of step 1 (Equation 3) is 243.4 kJ mol^-1. Given this information, determine the activation energy for the reverse reaction, Er, and comment on the significance of the value (one sentence only).

The fictitious compound, arrhenium fluoride (AfH ), reacts with itself to form a dimer with the formula Ah2F2 . The reaction is second order in AhF. The value of the rate constant is 8.591x10-3 M-1s-1. What is the initial rate of reaction in a reactor filled with AhF to a concentration of 5.5M ? Express your answer in M.s-1.

The half-life of a first order reaction is determined to be 85.5 years. How long will it take for the concentration of the reactant to reach 2% of its initial value?

At temperatures above 930 ∘C, PbO reduces PbS to form metallic lead (Pb). The byproduct of the reaction is SO2. Calculate the amount of lead produced (in kg) when a reactor is charged with 487.0 kg of PbS and 750 kg of PbO.

You wish to increase the carbon content of a slab of steel by exposing it to a carburizing atmosphere at elevated temperature. The carbon concentration in the steel before carburization is 359.5 ppm and is initially uniform through the thickness of the steel. The atmosphere of the carburizing furnace maintains a carbon concentration of 6695.0 ppm at the surface of the steel. Calculate the time required to carburize steel so that the concentration of carbon at a depth of 38.0 x 10-2 cm is one half the value of the carbon concentration at the surface. The diffusion coefficient of carbon in steel is 3.091 x 10-7 cm2/s at the carburizing temperature. Express your answer in hours.

DATA: Error Function Values erf(ξ

I need some help with biochemistry level 3 today. Any help would be appreciated

how are fossils formed

how does a basic synapse work?

The calcium ion has a charge of 2+ (Ca2+)

how is polythene made?

how many degrees of freedom do Helium atom have?

answer in moles

is it a good thing using 2 named transition metals as examples

how reactive are transition metals compared to group 1

how to get pure water from salty water using household objects

iv got information about it but dont know how to lay it out

How can we, I just don't get it, How can we use Alcohol.

How would soil pH change if you: a) added peat?

I was asked three questions... Describe photo stability of silver halides. Is decomposition of silver halides a redox reaction? Describe how these reactions are used in phhotography. I really dnt undastand and I am the only person in my class. I am scared to ask the teacher!!!!!!!!!!!