When your substance either; change color, start to smell, explode, form bubbles, precipitate, and/or get hotter or colder.
1635 miles/hr.
Hope this helps
How does the law of conservation of mass apply to this reaction: C2H4 + O2 → H2O + CO2?
Answer:
21: True
22: False
23: True
24: False
25: False
26: True
27: True
28: False
30: True
Explanation: Hope this is helpful :)
I believe its convention. Not a hundred percent sure though
