Answer:
D.
Explanation:
The rock that is left behind is there because it has resisted the forces of erosion.
Answer:
"The elements are arranged in seven horizontal rows,called periods or series,and 18 vertical columns,called Groups."
Explanation:
Risk*
Answer: 69.72 kg of cryolite will be produced.
Explanation:
The balanced chemical equation is:
To calculate the moles, we use the equation:
moles of 
= 
moles of 
= 
moles of 
= 
As 1 mole of reacts with 6 moles of
166 moles of reacts with = 
moles of
As 1 mole of reacts with 12 moles of
166 moles of reacts with = 
moles of
Thus is the limiting reagent.
As 1 mole of produces = 2 moles of cryolite
166 moles of reacts with = 
moles of cryolite
Mass of cryolite 
= 
Thus 69.72 kg of cryolite will be produced.
I would say that you should wear a lab coat, safety goggles, and gloves
when the teacher says so - not everything in a lab is dangerous, so
there is no need to always wear these. But when the teacher says you
should - then you should.
