Question

what type of change is observed ?
a) when iron and sulphur are heated to form a non-magnetic grey substance ?
b)when dry ice (solidCO2) sublimes at room temperature ? justifu your answer

Answer 1

a) Chemical change as a new substance (iron sulphide) is formed after the chemical reaction between iron and sulphur.
b) Physical change as only the phase of CO₂ is changed from solid to gas.