Covalent bonding occurs when electrons are shared between atoms. Double and triple covalent bonds occur when four or six electrons are shared between two atoms, and they are indicated in Lewis structures by drawing two or three lines connecting one atom to another.
%Mass
Ar C = 12 g/mol, Mr C₄H₁₀ = 58 g/mol, Ar H = 1 g/mol

or

Answer:
V2 = 2.88L
Explanation:
P1= 78atm, V1= 2L, T1= 900K, P2= 45atm, V2=? T2= 750K
Applying the general gas equation
P1V1/T1 = P2V2/T2
Substitute the above
(78*2)/900= (45*V2)/750
V2= (78*2×750)/(900*45)
V2= 2.88L