What is a mole in chemistry?

Answer 1

Mole is a unit of concentration in SI; a mole is equal to the molecular mass of a compound.

Answer 2

A very large number of objects

Answer 3

In chemistry, a mole is a unit used to measure the amount of a substance. It represents Avogadro's number of atoms, molecules, or ions, which is approximately 6.022 x 10^23. One mole of a substance contains the same number of entities as there are atoms in 12 grams of carbon-12.

Answer 4

In Chemistry, we measure things in u(unified mass), but this is really really really small. It is not a practical way to talk about things. (I mean, do you know what 3 u's looks like, cuz i don't) A man named Avogadro came up with a better system. He discovered how many atoms it takes to convert u's to grams. This way you can work with larger amounts than only a few atoms. It turns out that exactly 6.022 x 10 ^23 atoms will convert u's to grams.

So, let's first understand u's. These values are unique for each atom, molecule, compound etc.... For atoms, the magnitude (value) can be found on the Periodic Table. For example Cl is 35.45 u.

In context(questions):

1. How many ATOMS are in one mole of Chlorine? This is tricky only because there is extra information. A mole of any substance has the same number of atoms (6.022 x 10 ^23), because it is the conversion. The number of atoms in a mole doesn't ever change.

2. How many GRAMS ar in 2 moles of Chlorine? 70.90 grams. One mole contains 35.45, so two moles is twice that number, 70.90.

3. How many moles are in 90.0 grams of Cl? approx. 2.54 moles. This is backwards from the last question. Take the 90.0 grams and divide it by the number of grams in one mole (35.45).

My suggestion to you is that you should use conversion factors. If you can successfully do this you won't even have to understand why you are doing what you are doing. (Note: make sure you understand conversion factors first. The units must cancel. Any con. factor can be flipped)

Some useful conversion factors:

1 mole/ 6.022 x 10 ^23 atoms

#(off of periodic table)/ 1 mole

#in U's = # in grams so #in u /# grams

ECT..

Good Luck. This is a tough topic for a lot of Chemistry students.

Answer 5

mole, in chemistry, a quantity of particles of any type equal to Avogadro's number, or 6.02×1023 particles. One gram-molecular weight of any molecular substance contains exactly one mole of molecules. The term mole is often used in place of gram-molecular weight; e.g., one speaks of 18 grams of water as one mole of water rather than as one gram-molecular weight of water. The mole is a unit in the International System of Units (SI).

Source: http://www.answers.com/mole+?gwp=11&ver=2.3.0.609&method=3

Answer 6

The mole is a unit that measure the amount of a substance. One mole is equal to 6.022E23 atoms.

Answer 7

mole, in chemistry, a quantity of particles of any type equal to Avogadro's number, or 6.02

Answer 8

A mole in chemistry is a unit of measurement that tells us the quantity of a substance,

6 x 1023 atoms make up one mole

Answer 9

The mole of a substance is equivalent to the amount of this substance which contain as many molecules (or atoms or ions) as in 12 grams of carbon-12.

Answer 10

A mole is a unit of measurement in Chemistry that measures large quantities of very small entities such as atoms, molecules, or other specified particles.