Explanation:
Molar mass of HBr = 81 g/mol
Molar mass of nitrogen dioxide gas = 46 g/mol
Molar mass of ethane = 30 g/mol
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.
The formula for average kinetic energy is:

where,
k = Boltzmann’s constant = 
T = temperature = 273.15 K ( at STP)
As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.
So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.
Answer:
C. involve the attraction of opposite charges
Explanation:
<em>Ionic bonding</em> involves the attraction between <em>oppositely charged ions</em>, as in Na⁺ Cl⁻.
<em>Covalent bonding</em> involves the attraction between <em>negatively charged electrons and positivey charged nuclei</em>, as in a C-H bond.
A is <em>wrong</em>. Ionic bonding involves the transfer of electrons.
B is <em>wrong</em>. Covalent bonding involves the sharing of electrons.
D is <em>wrong</em>. Ionic bonds are usually stronger than covalent bonds.
Answer:
water vapor
because solid ice is a matter