The idea of the project is to create a Bluetooth enabled Active loudspeaker.

This is essentially a speaker that you connect to the mains to provide power and the audio signal is received wirelessly via bluetooth.

One wire has a capacitor-coupled signal to the input of the amplifier IC and both have grounds that are connected together.

Im still not 100% sure what you mean here. I understand that one wire is connected to the input of the AMP IC not sure about the other part though,

 

The bluetooth has two outputs that are a differential. Connecting an earphone to them does not need a ground connection.
The amplifier has a single-ended input using one wire plus another wire for ground.

Connect one output wire of the bluetooth to the amplifier's input through a series coupling capacitor that blocks the DC and connect the grounds of the circuits together.

 

what about the other output from the bluetooth chip, just leave it floating?

 

what about the other output from the bluetooth chip, just leave it floating?

Correct. It won't care about having no load.

 

Again this may seem a simple question, but which passive components need to have large power ratings.

 

A large power rating is needed by any passive component that gets hot.
Heat is produced by a resistance (or a transistor) with a voltage across it and a high current through it. The output transistors in a linear audio amplifier have a continuous voltage across them and a high current through them. Their emitter resistors have similar.

 

ive decided to go with the following components from uk.farnell.com

Order Code: 1565375 Description: RESISTOR, 1W 5% 2R2
Order Code: 1219204 Description: RESISTOR, 2R2 2 WATT 5%
Order Code: 8126933 Description: CAPACITOR, 1UF, 50V
Order Code: 1219468 Description: CAPACITOR, RADIAL, 220UF, 25V
Order Code: 9452729 Description: CAPACITOR, 0.1UF, 63V
Order Code: 8766762 Description: CAPACITOR, 22UF, 25V
Order Code: 1141778 Description: CAPACITOR, 0.22UF, 50V

 

Another quick question, how can a volume control be incorporated with this chip, would it simply be by adding a Variable resister to ground and to sweep the audio in to the input leg of the chip.

 

Another quick question, how can a volume control be incorporated with this chip, would it simply be by adding a Variable resister to ground and to sweep the audio in to the input leg of the chip.

The input pin of the TDA7240a amplifier has a DC bias voltage so the input pin must have a 1uF capacitor in series. The wiper of the grounded 10k audio-taper (logarithmic, not linear) volume control can feed the negative wire of the capacitor. The input of the volume control will probably need a coupling capacitor to block the DC from the output of the bluetooth. A 2.2uf capacitor can provide deep bass frequencies and its negative wire should be connected to the volume control.