Mole Definition and 127 Threads

So essentially I followed pretty much what is in the picture here in this solution. https://www.slader.com/textbook/9780134162430-chemistry-a-molecular-approach-4th-edition/242/exercises/79/ My question is essentially why does he do the 0.07XXX mol f2 * 2mol clf3/3mol f2 * 92xx g/2mol f2 =...

Hi all! I have a question ... I have to calculate the partial pressure of O2 Ccan I calculate the mole fraction from the data of 1 ppm of O2? The total pressure is 760 torr Thank you!

According to Wikipedia, its (quoting) the number of discrete atomic-scale particles in it divided by the Avogadro constant So a molecule of hydrogen would have an amount of substance of 2/NA and would have a mass of 2/(6*10^23) daltons?

Hello, I'm doing some refreshers before going back to school. Stat mech is my shakiest and I'd appreciate some help on this problem. I know that for a single particle, the partition function will be $$Z = 1 + 2e^{-\beta\Delta} + 2e^{-4\beta\Delta}$$ and so its internal energy is $$\frac{1}{Z}...

I have a couple of questions related to this task. The reaction that I proposed was this: NaOH(aq) + HCl(aq) <--> Na+ + Cl- + H2O (l) where as the solution manual have this net reaction, as nothing will happen with the Na+ and Cl- ions: H+ + OH- <--> H2O. I assume these reactions will...

My Textbook says this is the formula to find energy values for electron shells: $$E_{mol of electrons} = \frac{-1312kJ}{n^2}$$ where $n$ is in electron shell number But when we divide by 1 mol to get the energy value for each electron we get $$E_{electron} = \frac{-2.178 \cdot 10^{-18}}{n^2}...

Is there any difference between 1 mole of CH4 and 1 molecule of CH4? or they mean the same thing?

Homework Statement If mole fraction, pressure fraction and volume fraction are denoted by Xmol , Xp, XV respectively, of a gaseous component, then what is the relation between them? Homework Equations mole fraction = mole of component / total moles pressure fraction = pressure of component /...

Homework Statement 30 litres of N2 and 30 litres of H2 are taken in Habers process with 50% yield.What is the final composition of the compunds in litres? Homework Equations N2+3H2->2NH3 The Attempt at a Solution N2 + 3H2-> 2NH3 intial: 30 30 0 final: 30 - x/2 30-(3x)/2 (2x)/2 so, 30 - x/2 +...

As we know, in the case of an atom, 1 mole of C = 6.023 X 10^23 C atoms and in the case of a molecule, 1 mole of C molecule = 6.023 X 10^23 molecules. as we know, atoms are used to make molecules, So can I say 1 mole of C atoms make 1 molecule of C because what we get If we break 1 molecule of C...

As we know, Please point out if I am wrong here one molecule of CO = one mole of CO molecules = 6.223 X 10^23 number of CO molecules If I split one molecule of CO, we get one C and one O. Here are my questions, What to say these ''one C and one O" one mole of C atoms and one mole of O atoms or...

Homework Statement A sample of K (s) of mass 2.740g undergoes combustion in a constant volume calorimeter at 298.15K . The calorimeter constant is 1849 J/K , and the measured temperature rise in the inner water bath containing 1450 of water is 1.60K Calculate the internal energy of formation...

Homework Statement Homework EquationsThe Attempt at a Solution ## dS = \frac { dQ_{rev} } { T } ## Assuming that isothermal process is a reversible processes, ## dU = dQ – pdV## For isothermal process, dU = 0. ## dQ = pdV ## ## pV = nRT##, where n is number of moles. For one mole, ##...

I haven't had a chemistry class in many years. Recently I saw an interesting article that used a solution of resveratrol (228.25 grams per mole) in dimethylsulfoxide (78.13 grams per mole). The concentration was listed as 5 uMol. If I had 10 grams of DMSO how much resveratrol would I add to...

Homework Statement This question is problem 1.3.1 from Herbert Callen's textbook in Thermodynamics, second edition. In the answers I have the following: Mole fraction of NaCl = 0.057, molar volume =$18\times 10^{-6} m^3/mole$. How did they arrive at these answers? did they multiplied the...

In our laboratory class we were required to calculate the stock (mM) and final (µM) concentrations for Glycerol. The tutor said my final calculations were incorrect and that I had made an error. He didn't have enough time show me where I went wrong. I have compared my results with another...

Background: Amount of substance is a fundamental physical quantity which has mole (mol) as it's SI unit. Therefore all expressions for amount of substance should have the unit mole on simplification. Therefore, if A = Amount of substance (normally in moles), m = Mass of the substance in a...

Homework Statement :[/B] The density of a 2.05 molar solution of acetic acid is 1.02g/ml. The Molality of the solution is: (a) 1.14 mole/kg (b) 3.28 mole/kg (c) 2.28 mole/g (d) 0.44 mole/kg Homework Equations :[/B] The Attempt at a Solution :[/B] I tried it out very simply using unitary...

Homework Statement Here we divide the mole balance by the volume ##4*\pi## ##*## r2##*##dr and take lim as dr->0(standard procedure) 1) How exactly he makes the transition from equation from 6 to 7? Exercise #2(see below please) Solution for Problem#2 2)Why does he divide here by...

1)When Mg is burned in air,a mixture of MgO and Mg3N2 is produced.If 3,6g of Mg produces 5,7g of mixture,what is the percentage by mass of each compound in the mixture? 2)A solution of an acid having the formula H3NSO3 is prepared by dissolving 9,7g in water and making up the solution to...

How to convert mass fraction to mole fraction? Is it using the molecular weight?

Homework Statement Known: [/B] Mass of compound A: 15mg (weighed in excess), MM=200g/mol Mass of compound B: 6mg, MM=700g/mol Concentration of each compound listed above(Concentration of solution of compound A or solution of Compound B): 20mg/L Total concentration of the solution: 20mg/mL Molar...

Quarks in a Mole If I have one mole of hydrogen, I only have Up and Down Quarks, right? If I have one mole of Plutonium, I should have all the Quarks, right? Where on the Periodic Chart do all the Quarks start showing up?

An incomplete reaction of 12.125 g of propane proceeds as follows: 3 C3H8(g) + 14 O2(g) → 8 CO2(g) + 12 H2O(g) + C(s) How many grams of solid carbon residue are produced as a product? So, C3H8 C=3(12.01)=36.03 g/mol. H=8(1.01) = 8.08 g/mol. =...

Homework Statement Given ##(\frac{∂H}{∂U})_P = (\frac{C_V+ (π_T + P)*V*a}{C_V + V*a*π_T}) ## Calculate this value of 1 mole of ideal gas at STP that has constant heat capacity of 12.5 ##\frac{J*K}{mol}## n=1 T = 273.15 K P = 1 atm ##C_V = 12.5 \frac{J*K}{mol}## a = ? ##π_T = ?## Homework...

Homework Statement The reaction between aluminium powder and anhydrous barium nitrate is used as the propellant in some fireworks. The metal oxides and nitrogen are the only products. Which volume of nitrogen, measured under room conditions, is produced when 0.783 g of anhydrous barium nitrate...

Dear PF Forum, A: 1 mole O2 is roughly 32 grams? 1 mole ozone is roughly 48 grams? 1 mole CO2 is roughly 46 grams? Considering there are isotopes --------------------------------------------------------------- B: Do, at the same temperature and pressure, 1 mole CO2 and 1 mole O2 have the...

Homework Statement One litre cylinder contains 1 mole of the ideal gas molecules having the average kinetic energy of 0.1eV. What is the total energy of this gas? Homework Equations W = K + U The Attempt at a Solution I figured because the cylinder is closed, no stated temperature change, or...

I am confused about the concept of a mole. Avogadro's # says that 1 mole has 6.023*10^23 particles. Does it make sense to talk about moles in a non-integer sense? For example, can you say that 1/2 mole has 1/2*(6.023*10^23) particles?

Homework Statement How many oxygen atoms are there in one molecule of oxygen gas? How many oxygen atoms are there in one mole of oxygen gas? Homework EquationsThe Attempt at a Solution [/B] There are 2 oxygen atoms in one molecule of oxygen gas. There is 6.02x1023 oxygen atoms in one mole of...

Homework Statement What is the formula of a compound containing 3 moles of oxygen, one mole of aluminum and 3 moles of hydrogen in each mole of the compound? Homework EquationsThe Attempt at a Solution I don't really understand the question at all.

Homework Statement Homework Equations not sure The Attempt at a Solution First, I'm a bit confused as to what the mole fraction of the products mean. Can someone explain? Is it something to do about the total number of carbon and hydrogen atoms in methane, ethene and propene? Just can't...

1 mole of all gas has equal number of molecules irrespective of their size. So I just wanted to know when 1 mole of molecules exerts pressure on the wall of a container, will it be same for all gases, irrespective of their molecules sizes.

The most so called "difficult" topic in chemistry mole.I am Confused in it a lot..please clear the doubt. Firstly,The mass no of each elements means the mass Of how much atoms in the elements and relative to what.as we know we assume a prototype as scientist did named it as kilogram and then on...

Homework Statement There is a statement in a book : " Graph of P vs ##\chi## is a straight line which ##cannot## pass through origin" Homework EquationsThe Attempt at a Solution But if mole fraction of a component is zero then it can't form vapours because of which its partial pressure will be...

Homework Statement At 1 atm and 0° C, a 5.04 L mixture of methane (CH4) and propane(C3H8) was burned producing 20.9 g of CO2. Assume complete combustion. 1. How many moles total of methane and propane were present before combustion? 2. How many moles of carbon dioxide were present after the...

Why there is 1mole⇒6.022*1023 atom. Why there is not another number. How avogrado find that number exactely correct at that time where there was no instuments.

Homework Statement The chemical analysis of a fuel is determined to be: 84.60 wt% C, 11.12 wt% H, 1.95 wt % S and the balance, inerts. The fuel is consumed in a steam generating furnace with 33% excess theoretical air. The air is preheated to 190degreesC and enters the furnace at a gauge...

Homework Statement An ideal monoatomic gas undergoes the following cycle: from 1.) V1 = 1m3, p1=2.5kPa, T1=200k to 2) V2=1m3, p2=7.5kPa then to 3)V3=3m3, p3=2.5kPA, and 4) back to 1). a. Sketch b. How many mole of gas are in the process? c. Give the missing temperatures at positions 2. and 3...

Homework Statement My book says that if the ratio of the masses of the samples is the same as the ratio of the masses of the components then the two samples contain the same number of components. That part makes sense. But how do we know that the same number of components has to be 6.02 x...

Homework Statement Why does 25 atomic ppm oxygen mean 25 moles of oxygen in 1e6 mole Fe? Homework Equations # = mol*Avo The Attempt at a Solution I understand the ppm (parts per million) part. Hence why 25 ppm means 25:1e6. What I do not understand is how they go from atomic to...

1 mole of a substance equals the amount of grams needed for that substance to have 6.0221413e+23 (Avogadro's number) atoms in it, isn't it? In order to determine how many grams one mole of a substance is, I've learned that you just need to check the atomic mass number on your periodic table...

Homework Statement 5. The nuclei of atoms in a certain crystalline solid have spin one. Each nucleus can be in anyone of three quantum states labeled by the quantum number m, where m = −1,0,1. This quant number measures the projection of the nuclear spin along a crystal axis of the solid. Due...

This is a more general question: is it always true for a mixture that if we define M(average) such that m(total) = n(total) * M(average), where n(total) is the total number of moles of species in the mixture (summed over all species) and m(total) is the total mass of the mixture, then M(average)...

Homework Statement Consider the following aqueous solution at 25°C Cr2(SO4)3, 1.26 mol/L, 1.37 mol/kg Calculate the mole fraction, density and % w/w Homework Equations χ = n Cr2(SO4)3 / n Cr2(SO4)3 + n H2O Unit conversions ρ= g solvent / mL solution % w/w = mass solvent / 100 g...

Homework Statement We are given the fact that 0.12 mol NaOH reacts with 0.015 mol methyl salicylate (C8H8O3) to form disodium salicylate (C7H4Na2O3). We're asked to calculate the mole ratio of NaOH to C8H8O3, identify the limiting reagents, and find the theoretical yield. Homework Equations...

I've read a lot about the mole , avogadro's no. , molecular mass and such , but I can't seem to understand anything , and no , the wiki article wasn't helpful at all ! Put simply : 1- I read that the mole is the molecular mass expressed in grams , for example an Oxygen atom has 16 as a mass no...

Homework Statement The figure shows a PV diagram for 2.69 mole of oxygen gas in a sealed container. The temperature of state 1 is 21 C. Pressure is Pi. What is T3 and T4? http://s74.photobucket.com/user/teysure/media/phyiscs.png.html?sort=3&o=0 my attempt at solving the solution...

Homework Statement 120 mol/min of Propane (C3H8) is burned in the presence of air (21% O2 and 79% N2) in a furnace, two reactions occur: Complete Combustion: 67%, propane is burned to CO2 and H2O Incomplete Combustion: 18%, propane is burned to CO and H2O Oxygen is supplied at 70%...

Let's start with a generalized example: 3A + 1B -> 2C For the mole amount next to each molecule, am I always to consider these as relative to one another or absolute? Most of the videos I have seen are describing the above as "for every 3 moles of A and 1 mole of B you get 2 moles of C". I...