Chem Definition and 398 Threads

Just came back to school.. and I realize I've forgotten so many things! :cry: ARGG! >_< So if anyone can, I would really appreciate it you could help and show me how to do these problems asap!1) An element consists of 1.40% of an isotope with mass 203.973 amu, 24.10% of an isotope with mass...

4PH3(g) ------- P4(g) + 6H2(g) If, in a certain experiment, over a specific time period, 0.0063 mol PH3 is consumed in a 2.0 L container each second of reaction, what are the rates of production of P4 and H2 in this experiment. Any idea about this problem? divide 2.0 to 1.0 and then .0063 to...

Which course is best to do at summer school, Chemistry or Wold History w/Geography? Both classes are required, so I need to take one to make room for other classes in the Fall.

how good an insulator is asbestos? (thermal conductivity 0.15 W/ m K). I am trying to determine the thickness of insulation required to reduce the heat loss of a spherical container by half. The answer I calculated it to be is 0.2cm which to me doesn't seem right (too small?) but having no...

Reaction: CH_4 + 2H_2S <-> CS_2 + 4H_2 k_{eq} = 100 at a certain temperature An unkown amount of reactants were intorduced into a 1.0L bulb and at equilibrium 0.10 mol of CH_4 and 0.30 of H_2S were found. Calc \[CS_2\] at equilibrium. I don't seem to have enough information here. I can form...

In my chmeistry lab i use a pipet 5.0 ml of HCl and add it to a beaker. To this beaker I also added 5.0 ml NaOH. I stir the mixture and when a red litmus it turn to blue and when i put a blue litmus it stay blue. So that means its a base, but since its a mixture of an acid and a base shouldn't...

Hey can anyone help me with this question? What is the major product from the acid-catalyzed hydration of 3-methyl-2-pentene? a. 3-methylpentane b. 3-methyl-1-pentanol c. 3-methyl-2-pentanol d. 3-methyl-3-pentanol e. 3-methoxypentane Would the answer by D? My reasoning is that when...

1. if you want to draw the electron dot structure for say carbon (4 valence electrons) would you draw it with one dot on each side or two on one side, and one on two other sides? 2. can someone give me a link that helps discuss hybridization - i don't really get it and i need help...

it seems like most of the posts in this forum get moved to hw. come on now, can't we have any good chem topics that don't have to do with hw?

Does anyone have any links or places for me to look for a crash course in enthalpy, bombo calorimeter, and equations dealing with molecular weight or moles in general? I took a physics class worried about my lack of chemistry background, but everyone told me not to worry about it... Well...

I searched the internet for the answers and i keep coming up short maybe someone could help? 1. Which of the following is an empirical formula? a) C5H10O5 b) C6H12O2 c) C12H17OH Which of the following is an empirical formula? NaO C2H8N2 C6H3Cl2 What is the percent...

Could someone could help me with this reaction rate problem? 4PH3(g) ------- P4(g) + 6H2(g) If, in a certain experiment, over a specific time period, 0.0048 mol PH3 is consumed in a 2.0 L container each second of reaction, what are the rates of production of P4 and H2 in this experiment. I'm...

I need to include net ionic eq, phase symbols, etc. 1. Sulfur trioxide is heated with carbon dioxide. 2. A solution of strontium chloride is mixed with a solution of sodium sulfate. 3. Hydrochloric acid is added to sodium hydroxide My work: 1. SO3(g)+H2O(l)---->H2SO4(aq) 2...

[CHEM] Equlibrium Help please! Hi, I am having trouble with a few questions on my chapter review and I have a test tomorrow. I wasn't at school today so I didn't get the chance to ask questions. 1. The oxidation of sulfur dioxide to sulfur trioxide is an important reaction. At 1000K, the...

Hey everyone =) I am nearing my completion of the chemistry unit, and I have to do a huge lab report before I write my unit test..:frown: For the lab basically, we are comparing acid-neutralizing capabilities of baking soda and antacid substances. We are going to.. - mix measured amounts of...

What does the ic suffix mean in compound names? For instance ferric, plumbic, cupric? I'm guessing it has something to do with the charge on the metal ion? I have some nomenclature rules from my teacher but this isn't covered. Thanks.

HELLO EVERYONE can anyone help me wit this what is the role of chem. engg in new emerging fields i.e. BIOTECH.NANOTECHNOLOGY & ENVIRONMENTAL ENGG. DO REPLY

Ok so this problem pissed me off to no end... basically because ih ad 5 minutes to do it and couldn't figure it out. Now, i divided the 120g by the molar mass of PF3 and divided by .846 to find the actual amount necessary which gave me 1.612449659 moles. Multply that by the molar mass of F2...

2 a) Calculate the expected mass of one mole of 31^P atoms that the avogadro constant equals 6.0225 x10^23, the mass of one electron equals 9.1091x10^-28g, the mass of one proton equals 1.6725x10^-24g and the mass of one nuetron equals 1.6748x10^-24g. b) The actual mass of one mole of 31^P...

Could anybody tell me, in whatever units, how much energy per volume (and by mass if you know) is released by the most powerful chemical reactions?

Only three weeks into organic chemistry I, and I'm already feeling hopelessly confused. Can anyone recommend a good study guide or book to help clarify the basics, and explain the big picture? Thanks!

chem word problem ! please help Hi , This is a Hw question i have am stuck on i don't know how to solve it ... A pharmacist is to prepare 16 milliliters of special eye drops for a glaucoma patient. The eye-drop solution must have a 5% active ingredient, but the pharmacist only has 10%...

In the following calculation ( ( (5.70 x 10.02) − 7.2356) ÷ 0.014 ) + 1 the number 1 is defined as exact. Give the correct answer to this calculation with the correct number of significant figures. I am having a whole lot trouble with finding the correct significant...

I am currently thinking about choosing Chem Eng. as a major. I am very interested in what those who have this degree think about it. why is it a good/bad choice? what were some hard classes/subjects? where you plan on taking this degree? what are salaries like? I am interested in everything...

I've worked it out and due to offering limitations it will take me 3 more years to do the former, and 2 more years to do the latter. I've already been in university for 2 years. The courses I'd need in order to accomplish both are listed below: For the dual major in physics/math with...

ok, here's a tricky brainteaser, whoever solves it is incredibly smart uhh, actually, it's homework, and it seems pretty basic. Well, here it goes "explain how liquid water can go from 25C/1 atm to 30C/1 atm in a process for which q<0" I was thinking perhaps that since q=mc_p \Delta...

What an awesome site. Well I was wondering, i have a bunch of thermodynamics physical chem related questions to ask, where is the best place to ask them? are any of you good at thermodynamics, are there any experts here? :approve:

technically, I only need one or the other to pick up my chem minor, but I might take both. How valuable would they be to a physics major planning to go to graduate school? I would like to take them both, but would grad schools care all that much? I am honestly not sure where I want to do...

In the expression: ksp = (3.42 x 10^-7) (6.84 x 10^-7)^2 = 1.6 x 10^-19 I don't understand how the final answer is found. Can someone show me a step by step? I'm attempting to understand how to do these types of questions! Any help is greatly appreciated!

Hello all, what is the major difference in these majors? What kind of job would I get with the chem E degree, what kind of job would I get with the chem degree? I am currently leaning more toward the chemical engineering degree, but am not entirely sure.

Hi guys can you please check if this is right...thanks in advance The heat released by the reaction 2C + 2H2 = CH4 is 74.8kJ/mol. Using this information and a table of standard enthalpy of formation values, determine the heat of combustion for the burning of methane to form CO2 and H2O(g)...

Hi guys can you please check if this is right...thanks in advance Given the reaction CO2(g) + H2(g) = H2O(g) + CO(g). If initially there are 2.0 moles of CO2 (g) and 2.0 moles of H2(g) introduced into an empty 1.0L container, at 1800ºC, it is found that at equilibrium there are 0.3 moles of...

chem question...curious?! hi guys i was just wondering that if a solution of a weak acid has a salt of the same acid added to it, what would happen to the pH?? can anyone help me out...thanks in advance

Why do geometric isomers only exist in the alkene family but not in alkanes? What are different ways of increasing the rate of a chemical reaction?

ok my final exam for chem is tomorrow and i need help badly on this practice problem! here it is: 3. When 9.250 kJ of heat is added to 20.0 g of ice at 0.0 degrees Celcius, what is the final temperature of the water? The heat of fusion for water is 335 J/g. I don't know how on Earth to...

Hey guys i need some help. Most of these questions i already know the answer to but i just want to make sure I'm right. My final grade is riding on this 1) If given a chemical equilibrium reaction with the delta H, by comparing the rate of the final reaction, is it possible to find the...

Hello,there are some question about physical chemistry to be asked. :-p 1) The space vehicle,Gemini,started its journey in space with 322kg of liquid fuel, CH3NHNH2. This fuel is oxidised by dinitrogen tetroxide,N2O4,to form nitrogen,carbon dioxide and water.hat is the mass of...

Besides texts by Charles H Corwin and Stephen Zumdahl, what texts are recommended for Introduction or Fundamentals of Chemistry. My texts are at least a couple of decades old. :biggrin:

Hey, I have a question which asks me to provide two examples of how organic chem can be used to improve existing products and therefore provide solutions to newly identified health or environment problems. One example is unleaded gasoline, instead of leaded. What are some others? I've...

What is an "organic functional group" ? What relation does it have towards pH ?

CHEM EQUAtioNS HARD! hi can anybody show me if i am writing these equations right or not thanks Fe3+ + 6H20 -> F2(H20)6 3 + Fe(H20)6 3+ + h20 -> Fe(h20)5(OH) 2+ + H30+ when added HCL Fe(H20)5(OH) 2+ + 4Cl- -> Fe(OH)cl4 2- + 5H20 when added KSCN Fe(OH)cl4 2- + SCN- ->...

It has to do with sig fig. Froom what i know, when performing log in an equation, only the numbers are the decimal point are counted as sig figs. So if i have 0.1 M of acid, to find the ph, it would be : -log(0.1) = 1; since sig figs have to be AFTER the decimal point, is the correct answer 1.0...

A(g) <--- <--- 2B(g) + C(g) When 1.00mol of A is placed in a 4.00L container at temperature t, the concentration of C at equilibrium is 0.050mol/L. What is the equilibrium constant for the reaction at temperature t? Thanks for the help.

For this one, Could someone check my work? 1.What volume of a 15.0mol/L standard solution of hydrochloric acid will be required a make a 450mL of a 2.25mol/L dilution? \frac{15mol/L}{2.25mol/L}=6.67 *I think there is no unit for 6.67 =(6.67)(0.450L)=3L 2.Will it be possible for...

Calucation of ERRORS - CHEM! hi I am doing one of those determining calcium hardness in swimming pool water here just stuck on a few bits 1) how do i convert concentration (mol/L) -> ppm ( parts per milliion) example i am given concentration of calcium = 8.595*10^-4 M how do i get parts...

the question is: What is the pH of 1.50M of NH3? the answer i got was a pH of 4.54.. is that correct?

The ionization of water is an endothermic process. a.)What happens to the value of Kw as water is heated? explain.. b.) What happens to the pH of pure water as the temperature increases? and c.)as the temperature of pure water rises, will the water become mor acidic, more basic or remain...

Lets say you want to find the molar volume of a gas ( H_{2} specifically). So you basically use a Mg ribbon and find the volume of the H_{2} gas in a test tube with the Mg ribbon. The water fizzes and bubbles. I am having trouble finding the volume of H_{2} at STP. I used the formula...

The density of a substance is 1.37 g/cm3. Convert this into kg/m3. Remember that: 1kg = 103 g and 1 m = 102 cm. Express your answer to 1 decimal place (don't include units). what i did is 1.37g = 0.00137 kg 1cm^3 = 1*10^-6 ie (1/(10^3)) 0.00137 / (1*10^-6) = 1370.0 kg/m^3 is that...

When determining molecular shape, how do you know what the lewis structure shape will be? For example CO_{2} is linear and polar (sp hybridization). But about CS_{2} ? Is this also molecularly linear? Thanks :smile: