datasheet register address is not in HEX?
Those addresses are also in hex. 0x1F means the same as 1Fh. The XXh notation comes from Intel assembly syntax (source)

Those addresses are used to identify a device register in the I2C transaction and are orthogonal to the address of the device on the bus. In particular, the device address is given on page 17, as a function of how a certain pin is configured:



The device address 29h corresponds with a 150k pulldown resistor on the address configuration pin. Note that this is a 7 bit address; the 8th bit is used by I2C to distinguish reads and writes.