Amount of substance (quantitative chemistry)

Question 1

What is a mole (mol)?

Answer 1

• A mole (mol) is a measure of the number of particles (atoms, ions or molecules) contained in a substance. One mole of any substance (element or compound) contains the same number of particles – six hundred thousand billion billion known as Avogadro’s constant. The mass of one mole of a substance is its relative atomic mass or relative formula mass in grams.

Question 2

How do you find the amount of substance (number of moles) in a given mass of a substance?

Answer 2

• Amount (mol) can be found by dividing the mass of substance (grams) by the atomic or formula mass (g/mol).

Question 3

What is a limiting reactant?

Answer 3

• Sometimes when two chemicals react together, one chemical is completely used up during the reaction. When one chemical is used up, it stops the reaction going any further. It is called the limiting reactant. The other chemical, which is not used up, is said to be in excess.

Question 4

What is the concentration of solutions?

Answer 4

• Many chemical reactions involve solutions. The concentration of a solution may be given by the mass of solute per given volume of solution. For example, if 2.00g of solute was dissolved to form 1.00dm^3 of solution, the concentration oof the solution would be 2.00g/dm^3.

Question 4

What is the concentration of solutions?

Answer 4

• Many chemical reactions involve solutions. The concentration of a solution may be given by the mass of solute per given volume of solution. For example, if 2.00g of solute was dissolved to form 1.00dm^3 of solution, the concentration oof the solution would be 2.00g/dm^3.

Question 4

What is the concentration of solutions?

Answer 4

• Many chemical reactions involve solutions. The concentration of a solution may be given by the mass of solute per given volume of solution. For example, if 2.00g of solute was dissolved to form 1.00dm^3 of solution, the concentration oof the solution would be 2.00g/dm^3.