Answer:
Removing the dirty water and replacing with fresh water. also the fish containing in the aquarium change the system of aquarium.
Answer:
C. It decreases by a factor of 4
Explanation:
F1 = kq1*q2/r²
F2 = kq1*q2/(2r)² = kq1*q2/(4r²) = kq1*q2/(r²*4) = F1/4
Answer:
Explanation:
From the 1 g sample you have:
0.546 grams of cobalt chloride
1-0.546=0.454 grams of water
Now:
1) The salt
Of the 0.546 g, 0.248 g are cobalt (Mr=58.9) and the rest id Cl (Mr=35.45):


Dividing:

So the molecular formula will be:

2) The water
The water's molecular weight is M=18 :

Bonding with the Co:

The complete formula of the hydrate:

Answer:
SiH4
Explanation:
We must remember that the magnitude of intermolecular forces play a vital role in the determination of the boiling point of a substance.
The Si-H bond is the least polar among all the bonds in compounds listed in the question. This is because the electronegativity difference between silicon and hydrogen is very slim resulting in the formation of a nonpolar covalent bond.
The other compounds possess more polar bonds hence have a greater degree of dipole interaction between molecules and a consequently higher boiling point than SiH4.