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:
Thomson made the following conclusions: The cathode ray is composed of negatively-charged particles. The particles must exist as part of the atom, since the mass of each particle is only ∼ 20001start fraction, 1, divided by, 2000, end fraction the mass of a hydrogen atom.
Explanation:
<h2>Input =

, water and Output =

</h2>
Explanation:
The light reactions of photosynthesis use water and produce Oxygen, NADPH.
The equation for photosynthesis :
→ 
The process of photosynthesis in two stages -
- The first stage is called the light reaction in which the light energy from the sun is captured and converted into chemical energy stored in the form of ATP and NADPH
- The second stage is the process of conversion of ATP molecules to sugar or glucose (the Calvin Cycle)
For a light reaction -
Net Input is of,
, 
Net Output is of, 
<span>The copper would go under oxidation since it will be losing two electrons. Copper starts out with an oxidation number of zero, but in order to balance the compound of CuO with the Oxygen having an oxidation number of -2, a positive 2 is required</span>
It would be MnSO4
The (II) lets you know it’s the form with a 2+ charge and Sulfate has a 2- charge
These will cancel out making it plain MnSO4
If it was manganese (iii) sulfide the answer would be Mn2(SO4)3