What does the growing tension between Gatsby and Tom represented by in Chapter 7 of The Great Gatsby?

One social issue highlighted in Ch. 7 is infidelity among
spouses.  We see Daisy boldly kiss Jay in front of Nick and Jordan.  We see a sick
George Wilson tell Tom he finally realized something has been going on with his wife and
the implication is, of course, that she has been having an affair.  Another social issue
mentioned in the chapter is interracial marriage which is another reference, like the
one in Ch. 1, of Tom's bigotry and racial intolerance.  There is also the social issue
of cars.   The chapter opens with Nick personifying cars when he says that the cars
would turn into Gatsby's drive with hope and expectation only to turn away sulkily in
disappointment at the realization there is no party.  Daisy and Jay drive to New York in
Tom's car while he, Nick, and Jordan take Gatsby's car.  Tom lets George think he can
sell George Jay's car and that leads George to think later that Tom owns that car.  It
is Jay's car that Daisy drives and kills Myrtle Wilson
with.

The growing tension among the characters,
particularly Tom and Jay, is represented by the intense heat.  Daisy complains about it
being so hot and Tom chastises her for complaining whereupon Jay tells Tom to leave her
alone.  This begins the blow up between Jay and Tom.