Josiah and Alicia have been excited all week because their science teacher has arranged for a guest speaker to present a lesson to their class on Friday. The guest speaker is a chemist. She spends part of the time explaining methane to the class. The chemist tells them methane is a flammable gas that can be formed when organic waste decomposes in a landfill. Methane is also present in natural gas, which is a fossil fuel. When methane reacts with oxygen gas, compounds called carbon dioxide and water are formed. The following models represent that process.

Question

a. Methane is flammable, but carbon dioxide is not. Does this make sense? Why or why not.

(1 point)
Responses

No, it doesn't make sense, because we expect products and reactants to have different properties.
No, it doesn't make sense, because we expect products and reactants to have different properties.

No, it doesn't make sense, because a physical change took place.
No, it doesn't make sense, because a physical change took place.

Yes, it makes sense, because we expect products and reactants to have different properties.
Yes, it makes sense, because we expect products and reactants to have different properties.

Yes, it makes sense, because a physical change took place.
Yes, it makes sense, because a physical change took place.
Question 2
b. How would you expect the boiling point of methane to compare with the boiling point of water?(1 point)
Responses

The boiling points would probably be the same, because products and reactants always have the same properties.
The boiling points would probably be the same, because products and reactants always have the same properties.

The boiling points would probably be different, because products and reactants usually have different properties.
The boiling points would probably be different, because products and reactants usually have different properties.

It is impossible to tell, because chemical reactions don't give us any clues about the properties of products compared to reactants.

Answer 1

Question 1:
a. Methane is flammable, but carbon dioxide is not. Does this make sense? Why or why not?

Response:
Yes, it makes sense, because we expect products and reactants to have different properties.
(Rationale: Methane is a flammable gas that can burn in the presence of oxygen, while carbon dioxide is a non-flammable gas that is formed as a product of the combustion of methane. This is a typical behavior of reactants and products in a chemical reaction.)

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Question 2:
b. How would you expect the boiling point of methane to compare with the boiling point of water?

Response:
The boiling points would probably be different, because products and reactants usually have different properties.
(Rationale: Methane (CH₄) has a boiling point of about -161.5°C, while water (H₂O) has a boiling point of 100°C. Their different molecular structures lead to different boiling points, which reflects the general principle that products and reactants can have different properties.)