Answer:

Explanation:
Given that,
The dimension of a square chunk of plastic is 5 cm × 5 cm × 5 cm
Mass, m = 200 g
We need to find its density
Density = mass/volume
It will form a cube. It volume = side³
So,

Hence density is 
Answer:
Molecules are made of two or more atoms
Molecules are made of atoms of the same element or different elements.
Molecules range in size.
Explanation:
A molecule is formed whenever two or more atoms combine. Hence we can define a molecule as a combination of two or more elements that are combined chemically and can not be separated by any physical means.
Molecules may be composed of the same atoms as in O2, F2 etc or different atoms as in CO2, H2O, etc.
The sizes of molecules differ. Some molecules are quite small in size while others are quite large in size.
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Hydrogen ion reacts with zinc to produce
gas
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Answer:
False
Explanation:
The periodic table is in order of their atomic number. If that were true, helium would not come before boron, for example.