Answer:
First and seventeenth group.
Explanation:
Hydrogen is a special case as it has only one electron in its outermost orbital.
The hydrogen can lose or can accept electron easily.
Thus it can form positive ion similar to alkali metals and negative ion similar to halogens.
Thus it can fall into two groups
a) I group [Alkali metals]
b) 17th Group [Halogens]
if we did not use an excess of the BaCl2 solution it would decrease the mass percentage of sulfate in the unknown sample.
The net precipitation equation would be.
Ba2+(aq) + SO42-(aq) → BaSO4(s)
If BaCl2 (Ba2+) is not taken in excess then the precipitation would not be completed as some of the sulfate ions would still be remaining in the solution. This would decrease the mass percentage of sulfate in the unknown sample.
If some tiny pieces of filter paper still remained mixed with the precipitate(BaSO4) then the mass of sulfate would increase and it gives a high mass percentage of the sulfate.
mass percentage of sulfate = (mass of sulfate/mass of sample)*100
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Answer: The new pressure is 3 psi.
Explanation:
Given: 
= 12 psi, 
= ?, 
Formula used is as follows.
Thus, we can conclude that the new pressure is 3 psi.
Well a question to ask would be if the mass of the material has changed significantly as that would determine that the substance is radioactive or if there have been any high readings found by a Geiger meter in certain period of time
hope that helps
Answer:
tungsten
Explanation:
I hope it's helpful for you
