What happens when a substance undergoes a physical change? some physical properties change, but the substance keeps its identity. no physical properties change, and the substance keeps its identity. some physical properties change, and the substance changes its identity. no physical properties change, but the substance changes its identity.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".