Answer:
According to the Environmental Paper Network's Paper Calculator, it takes about 32 million BTUs of energy to produce 1 ton of virgin paper fiber. To produce 1 ton of recycled paper, it takes about 22 million BTUs.
so the answer could be it takes less Btu to manufacture recycled products than new ones
Answer : The molecular formula of the compound will be, 
Explanation :
Empirical formula : It is the simplest form of the chemical formula which depicts the whole number of atoms of each element present in the compound.
Molecular formula : it is the chemical formula which depicts the actual number of atoms of each element present in the compound.
For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.
The equation used to calculate the valency is :

As we are given that the empirical formula of a compound is
and the molar mass of compound is, 90.09 gram/mol.
The empirical mass of
= 1(12) + 2(1) + 1(16) = 30 g/eq


Molecular formula = 
Thus, the molecular formula of the compound will be, 
Answer:
Nitrogen
Explanation:
Nitrogen has 5 Valence Electrons.
And its atomic mass is also less than Bismuth.
There are other elements in the 5th row but this one has the lowest atomic mass compared to the others.
Answer:
Physical
Explanation:
because the erosion of the canyon did not change any of the chemical attributes of the rock it only changed the appearance. it may have changed the color which is an example of chemical properties but in this case, it is physical. But in other cases, you would refer to this type of weathering as mechanical weathering.
<span>The atomic number of a neutral atom is equal to the number of protons and the number of electrons of the atom. The atomic weight meanwhile is equal to the sum of the number of protons and number of neutrons.Hence we can say that the number of protons is 8 and the number of neutrons is 10. </span>