Moles Definition and 202 Threads

Homework Statement A box with adiabatic and rigid walls, has a volume of 5L. The box is filled with helium and has a balloon inside filled with oxygen. Initially the helium occupies a volume of 4L, is under a pressure of 1atm and is at a temperature of 300 K. The oxygen inside the balloon...

How many molecules are in 23 moles of oxygen? I don't get it, I know how to do other kinds like How many moles are there in 25 grams of water? and How many grams are in 4.5 moles of Li20? but I don't get it. THANK YOU in advance

I have the variation of the ideal gas equation: n = PV/RT Assuming that everything else is equal and only temperature rises that will mean there are more moles than before. Is that right? How can that be? Thanks for clearing it up.

I want to find the number of moles and I have the ideal gas equation as : n = PV/RT However I think I'm using the wrong units to find it, I want the answers in moles. n = (1 Pa * 1 m^3) /(8.314 JK^-1 mol^-1 * 1K) so would this give the answer x mol^-1?? I can't see how that would...

Homework Statement A typical sugar cube has an edge length of 1 cm. If you had a cubical box that contained 1 mole of sugar cubes what would its length be? I'm pretty sure I could solve this one if I had a better idea as to what a mole actually is...Thanks for the help

Homework Statement A 4.0 m^3 container of oxygen gas has a gauge pressure of 8x10^5 Pa at 25 degrees c. a) how many moles of oxy are present in the containe?r ANS: 1292 moles b)how many oxy molecules are present? ANS: 7.78E26 oxy (yes, i have the answers but i don't know how to get to them...

Hi everyone. I was doing a past paper. I got some of the question wrong about finding out Volumes and Concentrations Could you please Help me with these Question. I have enclosed the question sheet that has all the work done on it. If you can't see image properly then use this link...

Homework Statement A piece of solid Iron contains 2.5moles of atoms. Whats its mass? suppose one atom in 10^12 were missing one electron, what would be the net charge of the iron? Homework Equations The Attempt at a Solution atomic mass 192.22u so mass should be 2.5*192.22 =...

Arginine has a molecular formula od C6H14N4O2 How many moles of C atoms are there in 0.47 mole of arginine What is the equation I would use here

Homework Statement How many moles of NH3 are in 2ml of supplied solution: 0.2 M NH3 in 2 M Nh4NO3 Ans to be given in mmol Homework Equations Concentration = mol/ L The Attempt at a Solution Ratio of NH3 : NH4NO3 = 1: 10 2 / 11 = 0.182 ml 0.2 mol/L * 1L/ 1000ml * 0.182...

Homework Statement assuming that all the energy released by the oxidation of one mole of glucose to carbon dioxide and water can be stored in the form of ATP, how many moles of ATP can be theoretically produced from ADP at 37 C? Use delta G since it tells you how much work a reaction could do...

Homework Statement So I'm trying to solve a problem and it asks: If 1 ml of 10 N NaOH is added to a liter of the buffer prepared, how much will the pH change? I know how to solve the problem but one thing is really confusing me, how am I able to convert the 1 ml of 10 N NaOH into moles...like...

Homework Statement I am trying to calculate the gas formation volume factor for a reservior, however I am stuck when trying to find the value n - number of moles for a gas to plug into the equation to find Bg, this is what I know; Bg (gas FVF)= volume of gas at reservoir conditions /...

Homework Statement Sulfur dioxide reacts with the oxygen in humid air to produce sulfur trioxide. After the reaction, how many moles are left of: SO2, O2 and how many moles of SO3 were created?Homework Equations 2 SO2 + O2 --> 2 SO3 The Attempt at a Solution The limiting reactant is SO2, so...

Homework Statement Hi. I'm reaady to panic right now so if anyone could please take the time to answer my question I would HUGELY appreciate it! I seriously need to get this done soon as I also have a test tomorrow and i just want to cry because I'm getting nowhere... We did a lab...

Homework Statement Gas is contained in an 7.71 liter vessel at a temperature of 18.6oC and a pressure of 8.35 atm. Determine the number of moles of gas in the vessel. Homework Equations 1 mol= 6.03 x 10^23 # of moles= mass of the gas/molecular mass The Attempt at a Solution I...

Homework Statement A spherical balloon is inflated to a diameter of 36 cm. Assuming that the gas in the balloon is of atmospheric pressure (101.3 kPa) and is at a temperature of 20°C. (a) How many moles of gas are in the balloon? (b) If 21% of the molecules in the balloon are oxygen...

Homework Statement 1. A large closed bag of plastic contains 0.10 m3 of an unknown gas at an initial temperature of 10°C and at the same pressure as the surrounding atmosphere, 1.0 atm. You place this bag in the sun and let the gas warm up to 38°C and expand to 0.11 m3. During this process...

Homework Statement 0.75 moles of NH3 molecules contain how many moles of hydrogen? Homework Equations The Attempt at a Solution

Homework Statement Could you please explain to me what moles are and how it refers to Avogadro's Constant and why chemists use them? Thanks. Homework Equations There are no equations to my knowledge.. The Attempt at a Solution I know what moles are I think but I am not sure how it...

Homework Statement I would like to know how to calculate how much moles of gas I have in the following in a cylinder with a certain volume and pressure. The gas in the cylinder is a mixture of air, with added oxygen and helium, the mixture is 18% Oxygen, 36,6% Nitrogen, 45% Helium and 0,4%...

Homework Statement Given: (1/2) mol N2 + (3/2) mol H2 -> NH3 change in H = -46.11 kJ/mol If the number of moles of N2 are changed to 10 and the number of moles of H2 to 35, how much heat is generated if only 10% of the Nitrogen reacts? The Attempt at a Solution After setting...

Help! Moles in Phosphorus? I have a couple problems I can't figure out. 1. How many moles of phosphorus are present in 80.1g of phosphorus? a. 0.387 mol b. 2.59 mol c. 2.48 x 10(3rd power) mol d. 15.58 x 10 (23rd power) mol e. none of these 2. How many atoms...

Homework Statement How many moles of solute particles are present in 5.07 mL of 0.688 M Na3PO4? Use scientific notation with 3 significant figures! Homework Equations The Attempt at a Solution 0.00507 L of soln 0.688 M M= mol solute / L of soln 0.688 = x / 0.00507 .688 *...

I'm having problems with this question. A piece of copper wire has a diameter of 0.389mm. If copper has a density of 8.92g/cc, how long (in meters) should you cut a piece of wire to obtain 0.0141 moles of copper? I tried finding the volume of the cylinder and other things, but I'm...

Homework Statement I am doing an exercise from my physics book right now. I am given: 1 molecule of hydrogen corresponds to 3.7x10^-26 m^3 1 molecule of led corresponds to 2.99x10^-29 m^3 the ratio of these volumes is 1.22x10^3 Q: Determine that the order of magnitude of the ratio...

How many number of moles of molecules are there in 1 mol dm-3 of HCl? Is it correct to find it this way? Number of moles of HCl = 1 mol Number of moles of H2O = 1000/18 = 55.6 mol So, total number of moles = 55.6 + 1 = 56.6 molesIf i change the question of 3 mol dm-3 of HNO3, Then the total...

Homework Statement If you have 4.5 x 1020 molecules of SnO2, how many moles of O do you have? The Attempt at a Solution I'm really getting the hang of moles lately but what is bothering me in this question is 4.5 x 1020 molecules of SnO2. If it was one molecule, you would have 2...

Trying to get my head around moles and molarity. I ran into this problem. How many moles of O are in 4.5 moles of P2O5? Having trouble figuring it out, can anyone help?

If I have 5 moles of Hydrogen Iodide dihydrate, for example, what is the mass? I knw that I have to tke the number of moles times the molar mass to find the mass but what is the molar mass of the compound I suggested? Do I hve to include the extra 2H2O part when finding the molar mass? Thanks...

Homework Statement The overall chemical equation for the titration reaction is: OCl(aq) + 2 S2O3(aq) + 2H+(aq) 6 Cl(aq) + S2O6(aq) + H2O(R) If a titration requires 5.29 ml 0.256 M Na2S2O3, (i) how many moles of S2O32&(aq) were consumed in the titration, and (ii) how many moles of...

Homework Statement The volume was which was 50.0mL. Homework Equations The Attempt at a Solution

How many moles of ions are in 0.0200g AgNO3. Please help, i can't seem to set up the equation!

Homework Statement Consider the following reaction, which takes place in an autoclave at 250 degrees C and 800 atm. NH3(g) + 7/4 O2(g) --> NO2(g) + 3/2 H20(g) Into the reaction vessel has been placed 200 L of NH3(g) and 120 L of O2(g). The reaction is allowed to go to completion...

I have two problems that I have trouble with. One I attempted, but I don't think I came up with the right formula. Any help would be appreciated! Problem one Use the dilution relationship (Mi x Vi = Mf x Vf) to calculate the volume of 0.500 M NaOH needed to prepare 500 mL of .250 M NaOH...

Hi I need help with a Stoichiometry problem. I am complete lost. I don't know where to start, or how to to solve. 2H2 + O2 -2H2O. I know the formula balances and that is it. The questions is How many grams of H2O are produced when 2.5 moles of O2 are used? Thanks!

One area of chemistry I seem to make a lot of mistakes on is the mathematical side. Calculating moles and grams and percentages and that kinda stuff. Heres a few questions on my last test I got wrong Q1.) Copper reacts with concentrated sulfuric acid according to the equation: Cu + 2H2SO4...

Homework Statement I'm just going to preface this by saying I know zilch about chemistry, I'm not even sure how I passed it the last time I took it, which was in grade eleven. Is it possible for me to find moles of a gas with this information: volume: 100 m^3 of air The gas is a diatomic...

1. How many moles of O[SIZE="1"]2 gas are in 5.0L container of 4.0 atm and 288K?

Homework Statement A microscopic scientist is assembling sugar molecules (C6H12O6) from C, H, and O atoms. If he has 6.022x10^23 atoms of each type, how many grams of sugar molecules can he assemble? Which type of atom does he run out of first? Homework Equations 1 mol = 6.02x10^23 atoms 1...

Just a quick question about error analysis. Moles of Calcium ions in 10 mL = 6.0 x 10-4 ± 0.5 x 10^-5 mols I'm suppose to scale this number to Moles of Calcium ions in 250mL. So when I multiply by 25, do I multiply the error value as well? Or does it remain the same?

Homework Statement When 10.00 mL of a solution of strong acid is mixed with 100.00 mL of a solution of weak base in a coffee-cup calorimeter, the temperature falls from 25.7oC to 20.7oC. Determine q for the acid-base reaction, assuming that the liquida have densities of 1.00 g/mL and the same...

Is Molarity simply "moles per liter" Is Molarity simply "moles per liter"

Homework Statement Three moles of ideal gas are in a rigid cubical box with sides of length 0.380 m. Homework Equations What is the force that the gas exerts on each of the six sides of the box when the gas temperature is 24.0 C? What is the force when the temperature of the gas is...

ive been having a hard time with this question and any help would be appreciated. If the percent yield in the reaction of methyl iodide (CH3I) with water to form methanol (CH3OH) and HI is 50%, how many moles of methyl iodide will be required to prepare 0.1 mole of methanol? (Assume that...

Homework Statement I did an experiment and found the weight of CaC(2)O(4)H(2)0 to be 31.4966 subtracted by the weight of a crucible which is 31.2612. I put this for my weight of CaC204H20 (as I can't think of any other weight that it would be requested). I followed the next question...

Hi, I came across this statement and an explanation to this is greatly appreciated as I can't figure this out. "pH 0 means ~ 2 moles of H3O+ for each 100 moles water" ? Thank you.

Homework Statement The are temperature and pressure in a laboratory are 20 degree C and 1 atm. A 1L container is open to the air. The container is then sealed and placed in a bath of boiling water. After reaching thermal equilibrium, the container is opened. How many moles of air escaped...

1. How many moles in 3.00 g H2SO4? Ok first off I don't know to find this answer. I want to know how to find it not just being told the answer. Second I'm going to need to know how to calculate this from beginning to end please help?

Homework Statement Assuming the acid (pain killer) is monoprotic, calculate the moles of pain killer/hydrogen ion in a sample of an unknown pain killer using a titration: NaOH was added to a pain killer solution m[pain killer]=0.40g dissolved in 50 mL of distilled water [NaOH]= 0.15...