The number of particles in one mole of a substance is: Click again to see term 👆 1/25 THIS SET IS OFTEN IN FOLDERS WITH. The number of carbon-12 atoms in 12 grams of unbound carbon in the ground state. Avogadro's number, the number of particles in a mole, can be experimentally determined by first 'counting' the number of atoms in a smaller space and then scaling up to find the number of particles that would have a mass equal to the atomic or molecular mass in. The mole is defined as the amount of substance that contains the number of carbon atoms in exactly 12 g of carbon-12 and consists of Avogadro’s number (6.022 × 10 23) of atoms of carbon-12. The molar mass of a substance is defined as the mass of 1 mol of that substance, expressed in grams per mole, and is equal to the mass of 6.022 × 10 23. Key Point #1: The Mole. Mole- countingunit standing for 6.02 x 1023 particles Tells us how many particles of a compound are actually involved in a reaction. 1 mole = 6.02 x 10. 602,000,000,000,000,000,000,000 particles.
There are about 20 species of fuzzy moles (the kind that crawl around on the ground), and one kind of mole that might appear on your face, but today is a day for celebrating a different kind of mole. Today’s mole is a unit — one invented by a man named Avogadro.
Really, a mole is just a group of objects. You can think of “a mole” the same way you think of “a dozen.” You’re probably familiar with a dozen eggs, or chickens or planets. Moles are no different. You can have a mole of molecules or people or cheeseburgers. But there are a lot more than twelve things in a mole — there are 6.02 x 1023. That’s 602,000,000,000,000,000,000,000 things. Because the mole contains so many units, they’re most often used in chemistry is a way of measuring really really small things like atoms or molecules.
So a mole of water is 6.02 x 1023 molecules of water, which works out to be about 18 grams, or 18 mL. A mole of aluminum is about 26 grams. But to really appreciate how many molecules are in a mole it helps to think about things we can see. To do that, let’s try these comparisons from Daniel Dulek’s lesson about how big a mole is.
A way to think about the relative size of a mole?
If you had a mole of doughnuts, they would cover the entire Earth in a doughnut-layer five miles deep.
If you had a mole of basketballs, you could create a new planet the size of the Earth!
If you received a mole of pennies on the day you were born, and spent a million dollars a second until you died at 100, you’d still have over 99.99% of your money in the bank.
One mole of red blood cells is more red blood cells than exist in every human on earth right now. A mole of cereal boxes stacked end to end would reach from the Sun to Pluto 7.5 million times. A mole of turkeys could form sixteen earths.
Okay, so now that we know why a mole has 6.02 x 1023 things in it, what can we do with that information? Moles in chemistry are far more useful than moles in the ground, or on your face. They factor into all kinds of equations and important concepts in chemistry. Chemists think of moles or atoms like you and I think of a dozen eggs – we add them to recipes, order them from the store and calculate what we need based on how many we have.
What would a mole of fuzzy moles look like? Well, the pile of animals would weigh a little over half of the mass of our moon. Thankfully, there’s no chemistry equation in the world that calls for that many mammals. But if there was, you’d now know just how many mammals that would be.
Related Topics:More Chemistry Lessons
In these lessons, we will learn
- how to calculate the mass of a substance when we are given the number of moles (mole to mass conversion).
- how to calculate the number of moles of a substance when we are given the mass (mass to mole conversion).
The following diagram shows the conversion between Mole and Mass. Scroll down the page for more examples and solutions.Mole-Mass Equation
mass = number of moles Ă— molar mass
where mass is in grams and the molar mass is in grams per mole.
Moles to Mass CalculationWe can use the above equation to find the mass of a substance when we are given the number of moles of the substance.
Example:
Calculate the mass of (a) 2 moles and (b) 0.25 moles of iron. (Relative atomic mass: Fe = 56)
Solution:
a) mass of 2 moles of iron
= number of moles Ă— molar mass
= 2 Ă— 56
= 112 g
b) mass of 0.25 mole of iron
= number of moles Ă— molar mass
= 0.25 Ă— 56
= 14 g
Example:
Calculate the mass of (a) 3 moles and (b) 0.2 moles of carbon dioxide gas, CO2. (Relative atomic mass: C = 12; O = 16)
Solution:
a) mass of 1 mole of CO2
= (1 Ă— 12) + (2 Ă— 16)
= 44 g
mass of 3 moles of CO2
= 3 Ă— 44
= 132g
b) mass of 0.2 mole of CO2
= 0.2 Ă— 44
= 8.8 g
Example:
If an experiment calls for 0.200 mol acetic acid (HC2H3O2), how many grams of glacial acetic acid do we need?
Formula: m = nM
- Show Step-by-step Solutions
If an experiment calls for 0.500 mol CaCO3, how many grams of pure calcium carbonate do we need? Mass to Moles Calculation
If we are given the mass of a substance and we are asked to find the number of moles of the substance, we can rewrite the above equation as
Example:
Calculate the number of moles of aluminum present in (a) 108 g and (b) 13.5 g of the element. (Relative atomic mass: Al = 27)
Solution:
a)
b)
Example:
Calculate the number of moles of magnesium oxide, MgO in (a) 80 g and (b) 10 g of the compound. (Relative atomic mass: O = 16, Mg = 24)
Solution:
a) Mass of 1 mole of MgO
= (1 x 24) + (1 x 16)
How To Use Mole Chemistry
= 40 g
b)
Examples of mass to mole calculation
Example:
How many moles of acetic acid (HC2H3O2) are present in a 5.00 g sample of pure acetic acid?
- Show Step-by-step Solutions
Examples:
1. How many moles of NAOH are represented by 80.0 grams of NAOH?
2. How many grams will 3.5 moles of NAOH weigh?
Mole Chemistry Avogadro's Number
Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.
Define Mole
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