Sound waves are waves of growing larger and smaller, making it seem elastic through substances, such as air.
Explanation:
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Answer:
put a test tube over the opening, remove it and quickly put a lit splint near the mout or in the tube. if you hear a squeaky pop it is hydrogen.
Explanation:
hydrogen ignites in air.
Explanation:
The similarities between chemical and physical changes include change in state of matter and both process involve change in energy.
Chemical changes of a substance results in the formation of entirely new substances. These changes are not reversible.
Physical changes results in the change of the state of the substance which can be reversed.
However, both chemical and physical changes results in change of state of matter and both process results in change in energy.
Thus, we can conclude that the similarities between chemical and physical changes include change in state of matter and both process involve change in energy.
(it's alre answered but here it again 'NOTE: not my answer')