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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How many moles of the substance are in 2.5 g of lead?

How many moles of the substance are in 2.50 g of lead? What I did: Atomic mass of Pb: 207.2 amu (or g?) Applying unitary method, 1 mol of Pb -> 207.2 g; so, x -> 2.5 g $x = \frac{2.5}{207.2}= \pu{...
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Would 2 C₂ be 2 moles of diatomic carbon, or 4 moles of carbon?

Would molecules like $\ce{C2, H2}$, etc., be considered 1 mole of diatomic [element] or 2 moles of [element]?
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Photosynthetic rate calculation

What are the steps in calculating the photosynthetic rate ($\mu\text{mole}\ce{O2}/$ $\text{m}^2 / \text{min}$) for a leaf that has an area of $0.0025 \text{m}^2$ and a $\ce{O2}$ evolution rate of $...
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Calculating the molartity of DNA in a cell

In the following questions use a value of 3 for $\pi$, $6 \times 10^{23}$ for Avogadro’s number and 660 for the molecular weight of 1 bp of DNA. The volume of a sphere of radius r is $4/3\,πr^3$. ...
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607 views

Equilibrium constant calculation from concentrations

Consider the following equilibrium: $\ce{A2\ _{(g)} + 2B_{(g)} <=> 2AB_{(g)}}$ A chemist puts 8.0 moles of $\ce{A2}$ and 10.0 moles of $\ce{B}$ into an evacuated 1.0 L container. The system ...
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ions proportion [closed]

I have a precipitation reaction of this form: $\ce{Ca^{2+} + CO_{3}^{2-} → CaCO3}$ How many mole of $\ce{Ca^{2+}}$ ion is contained in a 200ml solution? I'd like to know how to calculate this, ...
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Calculating percentage composition after drying

A partially dried clay mineral contains 8% water. The original sample contains nearly 12% water and 45% silica. The percentage of silica in the partially dried sample is nearly 50% 49% 55% 47% I ...
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Mass of a gas sample

What method did John Dalton use to measure the mass of one mole of gases, for example, chlorine and hydrogen, to get their relative masses?
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Why do people still use the mole (unit) in chemistry?

I know that the mole is widely used in chemistry instead of units of mass or volume as a convenient way to express amounts of reactants or of products of chemical reactions. I'm wondering why people ...
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Copper oxidation

In an experiment we conducted, we heated 1.6 grams of copper dust, and got 1.7 grams of oxidised copper, (it probably reacted with 0.1 grams of $\ce{O2}$) and our goal was to find which of the two ...
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Why is the mole a unit of measurement?

I really can't understand why is the mole a unit of measurement and not just a constant. I mean, we use units to express things that we can measure but that are not countable, that are continuous - ...
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I have to write a Python program relating with molecular weight. Any insight?

Write a program that determines the molecular weight of a chemical compound based on the number of hydrogen, carbon, and oxygen atoms in the compound. You should use the following atomic weights: \...
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Are my calculations correct for this reaction?

So in the reaction $\ce{2AgNO3 + Cu -> 2Ag + Cu(NO3)2}$, which is balanced, I was given $0.1\text{ g}$ of $\ce{Cu}$ that reacted. Are my calculations correct that if $0.1\text{ g}$ of $\ce{Cu}$ ...
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How to find the molecular weight of a given gas based on its density?

The density of a gas $\ce{X}$ is $10$ times that of hydrogen. In that case, what is the molecular weight of gas $\ce{X}$? Well what I've done up to now is this: The molecular mass of hydrogen is $M(\...
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Why is the relative atomic mass of carbon not exactly 12?

Relative atomic masses of atoms of all chemical elements are numbers without units, being the value of proportion compared to $\frac{1}{12}^\text{th}$ the mass of the carbon atom. But the relative ...
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The mole is used extensively in chemistry, why not elsewhere?

In chemistry, the unit "mole" is used in many places, and is an important tool when working with quantities. I have not seen it used elsewhere--for example, we never count people or TVs with the unit....

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