Metals don't form covalent bonds because of the low ionization energes of the metal atoms. It is easier for them to release electrons rather than sharing it. But this is not always the case, there are some metals that can form covalent bonds.
Solutions are a type of mixture.
A solution is a homogeneous mixture of particles so small that they cannot be seen and cannot be filtered out.
Definition: Homogeneous mixture looks the same.
I grabbed these from my science notes, hope this helps.
Answer: Mitochondria. The mitochondria contains cristae.
Explanation:
Starting moles of ethanol acid = 0.020 mol
At the equilibrium 50 % of the ethanol acid molecules reacted
∴ Moles of ethanol acid reacted = 0.020 mol * 50 %/100 %
= 0.010 mol
Moles of ethanol acid remain = 0.020 mol + 0.010 mol = 0.010 mol
Moles of the product
gas formed are calculated as
0.010 mol CH3COOH * 1 mol
/ 2 mol CH3COOH
= 0.005 mol 
Therefore at the equilibrium total moles of gas present in the vessel are 0.010 mol CH3COOH and 0.005 mol 
That is total gas moles at equilibrium = 0.010 mol + 0.005 mol = 0.015 mol
Now Calculate the pressure :
0.020 mol gas has pressure of 0.74 atm therefore at the same condition what will be the pressure exerted by 0.015 mol gas
P1/n1 = P2/n2
P2 = P1*n2 / n1
= 0.74 atm * 0.015 mol / 0.020 mol
= 0.555 atm
a electron behavior is a subatomic particle whose electric i charge and the other one is a molecule and chemical bond that shares electrons