Answer:
1 mole of MgO contains Avogadro's number of molecules which is 6.023×10^23
molecules.
0.5 mole of MgO will contain 0.5×6.023×10^23
=3.0115×10^23 molecules
Answer:
donde estan las preguntas
Explanation:
Because Na has one too many electron to be stable, while Mg has 2. once they loose those electrons, they will be come ion. loosing one electron will give the ion a 1+ charge, and loosing 2 will create a 2+ charge
Answer: B. The molecules move faster and become less dense
Explanation:
Liquid is the state of matter in which particles are less tightly bound as compared to solids as they have weak inter molecular forces as compared to solids.
Thus when a solid is heated, the molecules start moving in random motion due to an increase in the kinetic energy. The molecules move apart as the forces will be weak and thus less molecules will be present per unit volume. Thus it will become less dense.
Answer: (3) Energy is absorbed as bonds are broken, and energy is released as bonds are formed.
Explanation:
1) The equation given is H₂(g) + Cl₂(g) → 2HCl(g) + energy
2) The energy is shown in the product side, so energy is a product of the reaction, so energy is release.
But this is just the net energy of the process. You need more insight to deal with the energy changes in the reaction.
3) Chemical bonds store energy; this stored energy is the potential chemical energy of the molecules.
When a chemical reaction occurs, the first stage is to brake bonds.
Braking chemical bonds requires energy to overcome the bond energy. Braking bonds always absorbs energy.
On the other hand, forming bonds always release energy.
The neat energy of the reaction is the difference between the energy needed to break bonds and the energy released when new bonds form.
So, regardless the fact that, in the chemical equation that represents the reaction a net energy release is shown, you know that energy is absorbed as bonds are broken, and energy is released as bonds are formed (option 3).
