Chemistry

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 -----.

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?

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.%.

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

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.

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

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

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?

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

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).

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

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

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

I really need to know all the fundamental facts about alkanes and alkenes - I have my exams in May!!!!

You would also have access to all the usual laboratory equipment. In your plan you must give: • the one factor you would change as you carry out your investigation (the independent variable); • one factor you would observe or measure to collect your results (the dependent variable); • one of the factors you would keep the same as you carry out your investigation; • the evidence that would support Lavoisier’s idea.

what is the trend associated by increasing atomic number and reaction with chlorine and oxygen?

Is lemonade an acid or an alkali?

Assuming 65 % of a human body is water (H2O) and the rest is mostly carbon (C), estimate the number of atoms in a human body

Nitrates are not tested forming a precipitate. Why not?

4.00g of lawn sand (a mixture of sand and ammonium sulphate) was weighed into a conical flask, and 25 cm3 of 2.0 mol dm-3 sodium hydroxide solution was pipetted into the same flask. The conical flask was boiled for 20 minutes, after which time all the ammonia had been driven off, because: (NH4) 2SO4 (s) + 2NaOH (aq) 2NH3 (g) + Na2SO4 (aq) + 2H2O (1) The residue in the flask was cooled and filtered to remove the sand. The filtrate containing unreacted NaOH was made up to 250 cm3 in a volumetric flask. 25 cm3 samples of this solution were titrated against 0.1 mol dm-3 hydrochloric acid using bromothymol blue as an indicator. HCl + NaOH  NaCl + H2O The mean titre was 20.0 cm3. Calculate the percentage of ammonium sulphate by mass in the lawn sand.

What does tetrafluoroethene contain that allows it to form a polymer?

copper 2 carbonate + hot dilute sulfuric acid will give what

show that calcium carbonate is stable at room temperature?what does this mean and how do i show it

If Zinc was designed to have an atomic mass of 100.0amu, what would the atomic mass of Si be?

What are 2 uses of carbon dioxide

school cross word

What are covelant and Ionic Bonds

I need their formulas too, if possible!

What are the names of the salts produced by hydrochorlic acid?

CuCO3 + H2SO4 --> CuSO4 + H20 + CO2

what is an addition polymer?

what is cracking

what is electrolysis

What is the bond order of the diatomic molecule BN

What is the chemical test for glucose?

When an acid and an alkali react which two substances are always made?

Where can you find sulphuric acid in your home?

Why are d-block elements not as reactive as s-block elements

why is calcium oxide more hazardous than calcium hydroxide?

I want to prepare copper sulphate using sulfuric acid. I have a sample of copper metal and a sample of copper carbonate. If I'm to use one of the materials which should it be and why

/write and balance three euations that have the abulity to produce hydrogen gas as a product

You may often come across a question "What gas turns limewater cloudy?" The answer to this question is well known. Carbon dioxide is the only gas that turns lime water cloudy. You may be wondering what is lime water used for. Limewater is an aqueous solution of slaked lime and you will find it in antacids, medicines and lotions. But one of its most noteworthy property is that it is used to absorb carbon dioxide from the air. In this article, we have answered all the questions related to the reaction of lime water and .

What happens when Lime Water reacts to Carbon Dioxide?

Carbon dioxide reacts with limewater to form calcium carbonate, which precipitates out of the solution. The carbon dioxide and limewater react to produce water in addition to the calcium carbonate. Calcium carbonate is chalk, and when it is produced, it precipitates and solid particles of chalk appear. The appearance of this solid makes the liquid appear ‘milky’. The white milky suspension/precipitate is caused by the formation of calcium carbonate. The characteristic carbon dioxide test, is checking that the limewater is milky. This is because chalk is precipitating in the limewater. Bubbling carbon dioxide through the solution for an extended period of time makes the solution become clear and colorless. This happens as the carbon dioxide forms acidic carbonic acid when it dissolves in the water, the carbonic acid (H2CO3) reacts further with the calcium carbonate. This chemistry is important in understanding how hard water is formed and then limescale is formed in kettles and hot water boilers.

Written as an Equation

In its equation form that makes:

How to test for carbon dioxide?

Now, we will answer how to test for carbon-dioxide. One of the most effective ways to test for carbon dioxide gas is the limewater test. When carbon dioxide reacts with lime water (calcium hydroxide solution), a white precipitate of calcium carbonate is produced. The solution of calcium hydroxide is limewater and if carbon dioxide bubbles through the limewater, it turns cloudy white or milky.

How does carbon dioxide turns lime water milky?

When limewater which is a solution of calcium hydroxide, reacts with the carbon dioxide gas, an insoluble solid known as calcium carbonate is generated. The equation of this reaction is given below:

Now, the question arises why the solution turns milky. Well, the answer is simple, The reason for the milky solution is that calcium carbonate which is produced as a result of this reaction is a white precipitate. This nature of calcium carbonate also helps us to test for the presence of carbon dioxide gas. All you have to do is to bubble the gas through a solution of calcium hydroxide. If the gas is carbon dioxide, then the solution will turn milky. If not then the gas which is subjected to the test is not carbon dioxide. If you continue to bubble the carbon dioxide gas through limewater, you will witness another acid-base reaction that will dissolve the precipitate to generate soluble calcium hydrogen carbonate. The equation of this reaction is given below: