For the equation q=cΔt, q=100KJ, initial temp=20 degrees celsius, final temp=31.4 degrees celsius and I need to find c. Do I need to convert the q value from KJ to J?

convering, depends on the units you want.

c=q/deltaT=100kj/11.3 C= 8.85kJ/C

and

c= 8850J/C

you have to specify units, and both answers are correct.

Yes, you will need to convert the value of q from kilojoules (kJ) to joules (J) in order to use the correct units for the equation q = cΔt.

To convert kilojoules to joules, you need to multiply the value in kilojoules by 1000.

In this case, q = 100 kJ, so to convert it to joules:

q (in J) = q (in kJ) * 1000

q (in J) = 100 kJ * 1000 = 100,000 J

Now you can use the value of q in joules (100,000 J) in the equation q = cΔt to find the value of c.