Explanation:
A change that does not cause any change in chemical composition of a substance is known as a physical change.
For example, mass, density, volume etc are all physical changes.
On the other hand, a change that brings change in chemical composition of a substance is known as chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Hence, following statements are identified as chemical or physical changes as follows.
(a) Oxygen gas supports combustion : Chemical change
(b) Fertilizers help to increase agricultural production : Chemical change
(c) Water boils below 
on top of a mountain : Physical change
(d) Lead is denser than aluminum : Physical change
(e) Uranium is a radioactive element : Chemical change
Answer:
volume is the amount of space something occupies
Explanation:
Answer: The answer is: " 7.81 kg " .
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Explanation:
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Note the exact conversion: 1000 g = 1 kg ;
0.00781 g = ? kg :
So: To convert "0.0781 g" ; to "units in kg" ;
→ we multiply the value: 0.00781 g ; by "1000" ;
So: Given: " 0.00781 g " ;
→ we move the decimal point "3 (three) spaces forward" ;
to get: " 7.81 kg " .
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Hope this helps!
Wishing you the best in your academic pursuits
— and within the "Brainly" community!
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Answer:
(not sure) The origin of all cells observed can be traced to previous cells
Explanation:
- not all cells convert energy (?) (this I'm not sure but think so? might be wrong tho)
- not all cells have cell walls e.g. animal cells only have the cell membrane, no cell wall
- Rocks and other nonliving things are composed of cells: non living things are composed of the elements and not cells (unless they were previously alive, then they contain dead cells)
Answer:
H₂²⁺(aq) + O₂²⁻(aq) + SO₃²⁻(aq) → SO²⁻₄(aq) + H₂O(l)
Explanation:
H₂²⁺(aq) + O₂²⁻(aq) + Mg²⁺(aq) + SO₃²⁻(aq) → Mg²⁺(aq) + SO²⁻₄(aq) + H₂O(l)
A careful observation of the equation above, shows that the equation is already balanced.
To obtain the net ionic equation, we simply cancel Mg²⁺ from both side of the equation as shown below:
H₂²⁺(aq) + O₂²⁻(aq) + SO₃²⁻(aq) → SO²⁻₄(aq) + H₂O(l)
