Its an analog sensor, it doesn't have a resolution. It has accuracy, sensitivity,
hysteresis/repeatability, tempco, noise, long-term drift. 450mV/kPa is the sensitivity.
Resolution applies when you digitize a signal, so with Arduinos this is going to be a
property of the ADC involved.
The datasheet doesn't give noise or hysteresis information, but usually silicon MEMS pressure sensors are fairly well behaved - the choice of ADC (and voltage reference) are probably limiting factors (although note the absolute accuracy is poor for this device - calibration required)
The sensor has a typical output range of 0.2volt to 4,7volt on a 5volt supply.
Or, better said, 4% to 94% of it's supply voltage.
Resolution is therefore 94% - 4% = 90% of the A/D used (10-bit for an Uno).
Or 1024*0.9= ~922 steps of the pressure span of the sensor.
Or 10kPa/922 = ~10.8Pa per A/D step.
More than 10x worse then your 1Pa expectation.