What substances are commonly formed during a chemical reaction but we can't see them?

well in order to answer this question you have to provide more information < 3

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

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