default slave address of the sensor for I2C communication ?

[ASofi]

[S.Ma]

If you want to put 2 identical sensors on the same i2c bus, the other sensor should have a different address. There is a sensor pin usually to change one bit of the slave address. This way, you can have 2 sensors. More same sensors is also possible if you use one extra gpio per sensor, or create another i2c bus by sw gpio bit banging...