Answer: physical
Explanation: freezing and melting are physical changes.
Moles of N2O5 = moles of NO2 * ( 2 moles of N2O5 / 4 moles of NO2
Hydrogenated vegetable oil is a preservative, thus, the correct option is D. Hydrogenated vegetable oil are used by food industries to prevent fat rancidity in order to give their product a longer shelf life. Hydrogenated oils are very good preservatives because all the enzymatic activities in the oil has been neutralized during the hydrogenating process.
