Chemical Reactions and Mass Conservation

The video tutorial explains the Law of Conservation of Mass, stating that mass cannot be created or destroyed in a chemical reaction. It uses examples involving hydrogen and oxygen to demonstrate that the total mass of reactants equals the total mass of products. The tutorial further explains that the number of atoms remains constant before and after a reaction, reinforcing the concept of mass conservation. The lecture concludes by summarizing the key points and reiterating the law's definition.

What is formed when hydrogen and oxygen chemically combine?

• Carbon dioxide

• Water

• Methane

• Hydrogen peroxide

How many grams of water are produced when 2 grams of hydrogen react with 16 grams of oxygen?

• 18 grams

• 22 grams

• 16 grams

• 20 grams

According to the law of conservation of mass, what happens to mass during a chemical reaction?

• It is created

• It is destroyed

• It doubles

• It remains constant

Why is no new mass created in a chemical reaction?

• Because atoms disappear

• Because atoms are destroyed

• Because atoms are created

• Because atoms rearrange

What is the total mass of reactants in the given example of hydrogen and oxygen?

• 16 grams

• 22 grams

• 18 grams

• 20 grams

How many molecules of water are formed from 4 atoms of hydrogen and 2 atoms of oxygen?

• 3 molecules

• 4 molecules

• 2 molecules

• 1 molecule

What remains constant in a chemical reaction according to the lecture?

• Number of protons

• Number of electrons

• Number of molecules

• Number of atoms

What does the law of conservation of mass state about mass in chemical reactions?

• Mass can be created

• Mass can be doubled

• Mass can neither be created nor destroyed

• Mass can be destroyed

What is the key takeaway about the number of atoms in a chemical reaction?

• They increase

• They decrease

• They remain constant

• They disappear

What is the total mass before and after the chemical reaction in the example provided?

• 16 grams

• 18 grams

• 22 grams

• 20 grams