Suppose the heat of neutralization had ben determined using a glass beaker instead of a polystyrene coffee cup. how would the measured value have been affected?

Glass has a much higher specific heat than styrofoam so more of the energy produced will go into heating the glass. This quantity of heat will be lost (unaccounted for) hence the delta t in the calculation will be too small and the heat of neutralization will be lower.

Tolerance to high levels of salinity