Chapter 2 - Chemical Reactions

Question 1

What’s the law of conservation of mass/matter?

Answer 1

It means that the quantity of matter (mass) remains the same before and after a change, whether it is physical or chemical

Question 2

Does the number of atoms change before or after a chemical reaction?

Answer 2

No, because of the law of conservation of mass/matter

Question 3

Do the atoms have a different mass before or after a chemical reaction?

Answer 3

No, because of the law of conservation of mass/matter

Question 4

What can you do if the chemical equation does not respect the law of conservation of mass?

Answer 4

Balance the equations

Question 5

How do you balance an equation?

Answer 5

1- Count the atoms in the reactants and the products
2- Add the coefficients (numbers in front of each element) one at a time and count the atoms every time
3- Keep going until balanced

Question 6

What is the “formula” for acid-base neutralization? Explain what this means.

Answer 6

Acid + Base –> H2O + Salt

= Acid (starts with H) with a base (ends in OH). This produces water and another molecule (salt).

Question 7

What is the “formula” for combustion? Explain what this means.

Answer 7

fuel + O2 –> CO2 + H2O

= Fuel that reacts with oxygen. This produces CO2 and water.

Question 8

What is the “formula’ for synthesis?

Answer 8

multiple reactants –> one product

e.g. CO2 + H2O –> O2

Question 9

What is the “formula” for decomposition?

Answer 9

one reactant –> multiple products

e.g. O2 –> H2O + CO2

Question 10

What are the three things you need to have a combustion? (fire triangle)

Answer 10

1. Oxygen
2. Heat
3. Fuel

Question 11

What are some examples of fuel for combustion?

Answer 11

• paper
• wood
• propane