Gallon of gas burned per hour during idling?

When you idle the car, does the engine specifications determine how much gas burned per hour? Do newer or older cars burn more gas idling? Does the engine horsepower determine how much gas you burn when the car is idling? How much gallons/hour do you think a 1989 honda accord lxi burns? What is the average gallons/hour older cars burn versus newer cars (after 2000). Do cars that burn more gas when idling also burn more gas when driving and do cars that burn less gas when idling also burn less gas when idling? Does the MPG of the car determine how much car it will burn when idling?

Yes it does.

A few general thoughts. The larger the engine displacement the more gas it uses at idle.
The newer the car, the I'm guessing the more technology, electronics, computer system etc, so a newer car should be more efficient at all speeds, including idle.
Things like proper spark plugs, properly operating fuel delivery, fully functioning mass air flow sensor,
good oil, clean air filter will impact efficiency.
Pure guess, car uses 1/2 gallon of gas per hour at idle.