so i know that one mole is 6.022*10^23 particles in 12g of a carbon 12 isotope. im confused in finding the amount of moles in a particular substane. there is a formula that determines it, i think its n=m/M, yet im confused with what it means..
# moles = grams/molar mass
48 g C. How many moles.
48/12 = 4.0 moles.
70 g Cl2. How many moles?
70/70.9 = ??
536 g AgNO3. How many moles.
536/169.9 = ??
The formula you mentioned, n = m/M, is used to calculate the number of moles (n) of a substance. Let's break down the meaning of each variable in the formula:
n: This represents the number of moles of the substance you want to find.
m: This represents the mass of the substance, usually measured in grams (g).
M: This represents the molar mass of the substance, which is the mass of one mole of the substance. It is measured in grams per mole (g/mol).
To understand how to use the formula, you need to follow these steps:
1. Determine the mass (m) of the substance you have. For example, if you have 25 grams of a substance, you would use 25g as the value for m.
2. Identify the molar mass (M) of the substance. This can be found on the periodic table by adding up the atomic masses of all the elements in the substance. Make sure the units are in g/mol.
3. Plug in the values of m and M into the formula n = m/M and perform the division. The result will be the number of moles (n) of the substance you have.
For example, let's say you have 40 grams (m) of carbon dioxide (CO2). To find the number of moles (n) of carbon dioxide, you need to know the molar mass (M) of CO2. By adding up the atomic masses of carbon (C) and oxygen (O) from the periodic table, we find that the molar mass of CO2 is approximately 44 g/mol.
Now, we can use the formula n = m/M:
n = m/M = 40g / 44 g/mol ≈ 0.909 moles.
So, you would have approximately 0.909 moles of carbon dioxide.
Remember to always use the correct units and to find the molar mass of the specific substance you are working with.