Which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions?
1. Oxygen gas changes to ozone during thunderstorms.
2. Freezing rain develops when a warm air mass overrides a cold air mass.
3. Carbon dioxide is produced by the combustion of gasoline in an automobile engine.
4. Fog forms from water vapor when the temperature drops below the dew point.
5. When coal, oil, and natural gas are decomposed in landfills they produce methane gas.

1. Chemical change

2. Physical change

3. Chemical change

4. Physical change

5. Chemical change

Explanation:

1) In this case the ozone of molecular formula O3 changes to oxygen of molecular formula O2.

2) The water presents changes in its liquid and solid phases, maintaining its composition.

3) After combustion, carbon dioxide is produced as a new substance.

4) The mist that is formed by drops of liquid water and the water vapor have the same chemical composition, that is to say that there is no new substance.

5) Methane gas is produced from coal, oil, and natural gas.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

your parents i think this could be it