you calculate all the letters together and it would be Zn2
The volume did not change, it remained at 20 ml
<h3>Further explanation</h3>
Given
20 ml a sample gas at STP(273 K, 1 atm)
T₂=546 K
P₂=2 atm
Required
The volume
Solution
Combined gas Law :

Input the value :

The volume does not change because the pressure and temperature are increased by the same ratio as the initial conditions (to 2x)
The ideal gas law:

p - pressure, n - number of moles, R - the gas constant, T - temperature, V - volume
The volume and temperature of all three containers are the same, so the pressure depends on the number of moles. The greater the number of moles, the higher the pressure.
The mass of gases is 50 g.

The greatest number of moles is in the container with Ar, so there is the highest pressure.
Magnesium oxide is an ionic compound with a very high melting point and which requires a large amount of energy for melting.
<h3>What are ionic compounds?</h3>
Ionic compounds are compounds which are formed between oppositely charged ions which are held together by electrostatic forces of attraction between the oppositely charged ions.
Ionic compounds are formed when metal atoms donate electrons to non-metals atoms to form ions.
Magnesium oxide is an ionic compound.
The nature of bonding is ionic bonding.
It has a crystalline lattice structure.
The forces of attraction is electrostatic forces of attraction.
It has a high melting point of 2,852 °C, and thus requires a large amount of energy go melting to occur.
Therefore, magnesium oxide is an ionic compound which requires a large amount of energy for melting.
Learn more about ionic compounds at: brainly.com/question/11638999