# Questions tagged [mole]

The mole is a standard amount of a substance A mole of a substance is a number of units (particles, atoms, molecules, ions, peas, hard candies, people, universes) equal to the number of atoms of carbon-12 in one gram of carbon-12, or an Avogadro's number of stuff. The mole allows us to relate real-word measurements to atomic scale phenomena.

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### What is the difference in writing these equations and way of explaining molecule from atoms [closed]

C + 2O gives $CO_2$ or $C +O_2$gives $CO_2.$ How can we differ between these two equation depending upon the way I wrote oxygen as to their products. Would they have different properties or ...
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### How many moles of silicon are in 29.558g Silicon dioxide [closed]

The mass of SiO2 = 29.558 How many moles of silicon are in this amount
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### Are the units of mole of oxygen molecules the same with the units of mole of nitrogen molecules?

Suppose we have in a box $3 \,{\rm mol}$ $\ce{O}$ and $3 \,{\rm mol}$ $\ce{N}$. Is the addition of these two quantities meaningfull? We do it all the time when we want to find the molar fraction. I ...
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### What is the intuition behind 'mol' as a unit 'symbol'

Why are moles written with 'mol' as opposed to something which is easier to write with one character, or even two?
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### Calculating the amount of moles from given number of atoms [closed]

Complete the sentences below by doing the mole calculations: i)In $\pu{20 mol}$ of copper(II) phosphate, there are ______$\pu{mol}$ of copper ions and ______$\pu{mol}$ of oxygen atoms. ii)A sample ...
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### Mass percent and mole percent of a composition

The Problem A gas mixture contains hydrogen, carbon monoxide, and carbon dioxide. Calculate: a) The mass% hydrogen if the mixture contains 15 mol% $\ce{CO}$ and no $\ce{CO2}$; b) The molar composition ...
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### Moles of chlorine gas needed to make up an equivalent amount of saturated salt solution

Iām trying to solve a question about a saturated salt solution but am unsure of how to answer one of the parts or what itās asking for. The Problem The maximum solubility of table salt (NaCl) in water ...
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### How did the temperature in the solution with a lower concentration of CuCl2 increased in a faster rate?

My lab assignment is about the reaction between $\ce{CuCl2}$ and Aluminium and we tracked the temperature of the solution every 15 seconds and we needed to make our own experiment to check how ...
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### Confusion about Titration Formula [closed]

When performing a titration of a monoprotic acid and a monoprotic base, water can not be added to the titrant but water can be added to the analyte. To prove this statement to myself, I decided to ...
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### What is the difference between stoichiometric coefficients and number of moles? [closed]

Please clear my doubt, Thanks!
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### Why is molality per mass solvent rather than per mass of solution?

Knowing the moles of substance per mass of solution would be useful. Pour some solution and you'd know how much substance you have. Why is molality defined not this way, but as moles of substance per ...
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### Determining heat capacity of gasses

I need a little help on answering a question which popped into my head while I was reading about gas laws: Suppose that I have three canisters, each holding a different gas of unknown identity [...
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### What is the use of both mol and mass representing the same thing i.e. amount of something? [closed]

A mol is a unit but also has a magnitude. How can a unit have a magnitude? And if mole is used to measure an amount of substance than what does mass measure?
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### How do I solve this problem on mass balance from blast furnace iron making?

Question An ironmaking blast furnace produces hot metal of the composition: $\pu{93.6\%}$ $\ce{Fe},$ $\pu{2.1\%}$ $\ce{Si},$ $\pu{3.6\%}$ $\ce{C},$ $\pu{0.7\%}$ $\ce{Mn}.$ The composition of the iron ...
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### How to calculate the relationship between the pressures of zinc, carbon monoxide, and carbon dioxide based on mole balance?

Zinc oxide is reduced at a constant temperature in a closed reactor using $\ce{ZnO(s)}$ and $\ce{C(s)}$ as the only starting materials. The following reactions are assumed to be at thermodynamic ...
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### How do I determine molality from mole fraction without knowing how much of the solution I have?

What is the value of $x$ if $x$ molal solution of a compound in benzene has a mole fraction of solute equal to 0.2? I tried calculating the moles of $x$ through the value given but there are two ...
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### Molecular weight of NiMnGaFe compund problem

I have a big problems calculating molar/molecular etc masses, because in my case I have a monocrystal, co I cannot imagine it as a molecule and my compound is made of Ni-Mn-Ga-Fe. I know the mass and ...
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### Why there is a need of independent definitions for both mass and mole?

Considering that the two quantities are linked by reality, how can be both imposed by independent definitions? I am aware that the change taking place next May does not effect common weighing in ...
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### Help required for the calculation of moles [closed]

If 4.5ml of yeast prep + 0.5ml of 0.25 M glucose is separated into 2ml in 2 similar flasks. How many micromoles of glucose are there in one flask? Using M1V1=M2V2 (0.5ml/1000)*0.25M = M2 * 2ml = 0....
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### Why has the mole been redefined for 2019?

The mole is still defined as an SI unit representing the number of constituent particles (whether they be atoms, molecules etc.) in 12 grams of carbon isotope 12 (carbon-12). Effective from May 20 ...
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### An aqueous solution of NaCl has a mole fraction of 0.21. What is the mass of NaCl dissolved in 100.0 mL of solution? [closed]

Work mole fraction of NaCl = 0.21/0.21+0.79 If there is 1 mol of total solution, there will be 0.21 mol NaCl and 0.79 mol H2O 0.21 mol NaCl = 12.27 g 0.79 mol H2O = 14.23 g this would yield a ...
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### What is the smallest molar volume?

I wondered how small a volume a mole of material could occupy, so I started with carbon, which would need 12 grams. That's 60 carats, and there happens to be a famous 60 carat diamond. If my density/...