The correct answer as to which observation most likely indicates that only a chemical change has taken place would that the change cannot be reversed.
When it comes to changes in a system, it can either be:
- physical change
- chemical change
When a substance undergoes a physical change, the original version of the substance can be recovered. In other words, physical changes can be reversible.
When a substance undergoes a chemical change, the original version cannot be recovered because an entirely new product would have been formed. In other words, chemical changes are irreversible.
Thus, once a change becomes irreversible, such a change is said to be a chemical change.
More on chemical change can be found here: brainly.com/question/1161517
Answer:
question 3: A
question 4: products and reactants
Explanation:
D. Cell membrane: surrounds a cell and allows substances to pass in and out
Molar mass of methanol=12 + 1×3 + 16 + 1=32g
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