GCSE Chemistry - The Mole (Higher Tier) #25

The video tutorial explains the concept of moles in chemistry, using Avogadro's constant to define a mole as 6.02 * 10^23 particles. It describes how moles relate to mass and relative formula mass, providing examples with carbon, oxygen, and CO2. The tutorial demonstrates how to calculate the number of moles in a given mass and vice versa, using ammonia and carbon dioxide as examples. It also covers how to determine the mass of a specific element within a compound. Finally, the video explains how to interpret chemical equations in terms of moles, emphasizing the importance of mole ratios in reactions.

What is the significance of Avogadro's constant in chemistry?

• It calculates the speed of chemical reactions.

• It defines the number of particles in a mole.

• It determines the color of a substance.

• It measures the distance between atoms.

How do you calculate the number of moles from a given mass?

• Multiply the mass by the relative formula mass.

• Add the mass to the relative formula mass.

• Divide the mass by the relative formula mass.

• Subtract the mass from the relative formula mass.

If you have 42.5 grams of ammonia, how many moles do you have?

• 1.5 moles

• 2.5 moles

• 3.5 moles

• 4.5 moles

What is the mass of three moles of carbon dioxide?

• 220 grams

• 176 grams

• 132 grams

• 88 grams

In a chemical equation, what does the ratio of moles represent?

• The speed of the reaction

• The energy released

• The proportion of reactants and products

• The temperature change