It should tell you in the user instructions or installation manual, or on a nameplate.
However, you can estimate the load by converting btu/hr into watts then dividing by the voltage you're using (e.g., 220, 110).
10,000 / 3.412.. is 2931 watts. At 220 volts it would draw 13.3 amps (or slightly more for inefficiencies in the compressor, fan, etc), while operating normally. Because this is more than 80 percent of the next-lower-rated breaker of 15A, you would install a 220-v breaker for a minimum of 16A (i.e., the next available size for your panel).
a 2p 20 amp should work fine for a single 220 air conditioner,
About a tenth of a ton.
If the power requirement is 120 volts it will be connected to a single pole breaker rated at the amperage requirement of the air conditioner. If the voltage of the air conditioner is 240 volts, then a two pole breaker will be required.
Try adding a cercuit breaker right on the AC.
A 20 amp breaker might actually be needed for the installation. It depends on the wattage and voltage of the window air conditioner.
Number 10 thnn copper wire.
The wire is sized to the maximum overcurrent protection device (Max circuit breaker) ampacity. This is listed on the nameplate of the outdoor condensing unit. Size the wire to match the breaker.
The breaker type be it a single pole or double pole will depend on what voltage the air conditioner operates on. Once the voltage is established, the sizing of the breaker depends on what the current draw of the air conditioner is.
A 12000 BTU air conditioner draws close to 15 amps. While it technically can run on a 15 amp breaker, you may want to use a smaller air conditioner to be on the safe side.
Yes, call a certified technician to do the replacement of the freon.
It is a 1-1/2 ton: 18000 BTU (unit size)/12,000 BTU (per ton)=1.5
It is possible if the circuit breaker has tripped or is faulty. The best way to check is by unplugging the air conditioner, and plugging in a table lamp. If the lamp lights up, then you know that the circuit breaker is working, if not then it is faulty.