Suppose your thermometer is off by 1.5 oc i. e. it reads values that are 1.5 oc higher. how would this affect the results in this experiment? (3 pts)

I assume that the experiment is about calculating the enthalpy of a reaction. 
If you consistently use the thermometer for all procedure in the experiment, the effect will be negligible because all temperature will be increased by 1.5 °C.

In enthalpy calculation, the energy is determined by the temperature differences. If the final and initial temperature increased by 1.5 °C, then the difference will not be changed.

Compound with sulfer  is bright red