Mole Definition and 123 Threads

Homework Statement What is the total number of atoms in the molecules? NH3 - 2.5 mole Homework Equations Would you multiply the number of atoms in NH3 by Avogadro constant to find the number of atoms? (4 atoms)(6.02*10^23) =answer Or would you multiply the number of moles by Avogadro...

this problem should be simple, but i must be doing it wrong. At 250 degrees Celsius, a certain liquid X has a vapor pressure of 900 mm Hg and a second liquid Y has a pressure of 600 mm Hg. What is the minimum mole fraction of X necessary for the mixture to boil at this temperature (assume...

1.0 g of Iron metal reacts with 2.0 g of chlorine gas to make iron (III) chloride, FeCl3. (a) Write a balanced equation for this reaction. (b) Which of the reactants is present in excess ? (c) What mass of this reactant will be left over at the end of the reaction ? (7 marks) Homework...

Homework Statement I have to find the mass of HCl (in grams) that is produced given the below reaction yields 18.7g of H3PO4. Homework Equations PCl5 + 4H20 -> H3PO4 + 5HCl The Attempt at a Solution I calculated the # of mols for H3PO4. I want to confirm if this mol value...

Homework Statement can anyone help me with this problem...i can't seem to figure it out: A 1.222 M solution of a compound in water has a density of 1.3250g/mol at 20 degrees Celsius. what is the mole fraction of this solution? the compound has a molar mass of 97.80g/mol. Homework...

what's the relation be zmole (zettamole) and mole? thx!

Look at a mole. They have eyes, but they are small, and often completely covered by fur. I'm not a biologist, but I'd venture to guess that many are completely blind. If this is a design from an intelligent being, all I can say is WTF?

Mass ratio of N,P,K is 10 11 14, what is the mole ratio? a) 14, 11, 10 b) 28,11,10 c) 20, 10, 10 The answer is C) but i don't understand how to get there... can anyone help me get started?

Hey guys, I'm back, finished my term in physics with a 96% final grade, thanks to all you guys. So i thought id try you guys before i went to find a chemistry help forum. I get the Mole Concept, kinda, here's an example question (i got an answer, not sure if its right, we don't get a "back...

I have this mole, and it looks like skin cancer and I am getting it looked at on the 5th, I went into see my doctor about it awhile ago she was kind of useless she said "to just keep an eye on it" I went to another doctor recently who referred me to a dermatologist, I would be really mad at the...

Can someone explain to me what 12 grams of carbon 12 is and how to use avogrados number?

I’m trying to understand some research about naked mole rats. Apparently they don’t feel pain. Ref: Science Daily, http://www.sciencedaily.com/releases/2003/11/031117073925.htm Can anyone give me some background here? How is substance P manufactured by the body? In what cells is it made...

1. 75g sample of a gaseous mixture contains .51 mole fraction propane. The remainder is butane. What are the masses of propane and butane? 2. X = mol A / mol total The Attempt at a Solution P = mol propane B = mol butane I tried doing .49P + .49B = X mol propane and .51P + .51B...

Does X=n? X is the element fraction in a compound, and n is the mole number of an element.

Hey there, I've been trying for the past 45 minutes to work on my online homework but I have made hardly any progress. Here are the 2 problems I'm having trouble with: 1- Calculate the number of molecules of NBr3 in 37.5 g NBr3. Use a molar mass with at least as many significant figures...

I have almost my entire worksheet done but I wanted to check my answers and get some help with the final question.:smile: What is the mass of one mole of aluminum? The mass of one mole of aluminum is 26.981 grams. What is the mass of one mole of hydrogen? 1.008 g What is the...

1) Find the molar mass of an unknown substance if 227.5 mL of an aqueous solution containing 2.785 grams of the unknown generates an osmotic pressure of 588.0 mm Hg at 20.9 Celsius. Report your answer to 3 significant figures. pi = MRT pi = 588.0 mm Hg = 588 mm Hg/760 mm Hg = 0.7736842...

An aqueous antifreeze solution is 37.0% ethylene glycol (C2H6O2) by mass. The density of the solution is 1.047 g/cm3. Q: Calculate the mole fraction of ethylene glycol. I tried it many time, but still got the wrong answer. that is what i did: mole fraction:(X) = nA/(nA+nB) set the...

2.95 mol Ba(OH)4 to atoms. (I think I wrote this problem wrong. It might be (OH)2 instead). I'm confused >.< Do I: 1) multiply 2.95 mol by 6.02 x 10^23 atoms or or 2) multiply 2.95 mol x 6.02 x 10^23 molcules x 9 atoms. or is it something else? Also, how do I do these? Calculate the...

i know this is basic suff, but forget it, can u please tell me how to do this question how much work is done in moving a mole of electrons around a circut using a 6v voltage( 1 mole of electrons is 6.023 x 10 power 23 electrons thanks answer is w = qv = 5.78 x 10power5j

Hello, I am been tinkering about chemistry and they are bunch of things I don't get. I know I am asking stupid questions; that is why I didn't ask my teacher. First of all, Why is mole 12g of carbon-12? How does the mole help us? Since everything is made out of the elements listed in...

does anyone know how to do this problem? The total vapor pressure above a solution of C_6H_6(l) and C_7H_8(l) is 0.485 atm. What is the mole fraction of C_6H_6(l) in the liquid solution? P^o C6H6(l) = 0.526 atm P^o C7H8(l) = 0.188 atm the answer is 0.879 but I'm not sure how to get that...

In the chlor-alkali industry, Cl2(g) and NaOH(aq) are produced by electrolysis of an aqueous solution ofo sodium chloride. If a 1000L tank of NaCl(aq) at pH 7 is electrolysed for one hour with a current of 1.00x104A, the final pH will be: I am completely stuck on how to find the solution to...