atoms definitions and I hope this helps
Answer: Rhenium is used as an additive to tungsten- and molybdenum-based alloys to give useful properties. These alloys are used for oven filaments and x-ray machines. It is also used as an electrical contact material as it resists wear and withstands arc corrosion.
Explanation:
Answer : The number placed in front of
should be, three (3).
Explanation :
Balanced chemical reaction : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.
The given unbalanced chemical reaction is,

This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of chloride and sulfate ion are not balanced.
In order to balanced the chemical reaction, the coefficient 3 is put before the
, the coefficient 2 is put before the
and the coefficient 3 is put before the
.
Thus, the balanced chemical reaction will be,

Therefore, the number placed in front of
should be, three (3).
We are given with a hydrate with a mass of 6 grams and after heating the mass and cooling afterward, the mass went down to 3.27 grams. The amount of water in the hydrate thus is 6-3.27 g or 2.73 grams.That is equivalent to 45.5 percent by mass water.