Which of the following options correctly describe physical and chemical properties? A- A phase change always occurs when a physical property is measured B- When a chemical property is measured, the substance being observed is converted to a different substance or interacts with another substance. C- A chemical property of a substance can be observed without changing its composition or interacting with another substance. D- A physical property can be observed without a chemical reaction.

A physical property is a property (of any substance) that can be observed without the substance undergoing any change in identity nor does it require a chemical reaction to determine. For example, colour and size are physical properties that are part of the identity of a substance and can/must be observed without a substance undergoing any change or chemical reaction. This explanation makes option A wrong and option D right.

A chemical property of a substance is the property that relies on the ability of that substance to undergo a chemical reaction/interaction with another substance to form a new/different substance. For example, ability of a substance to react with an acid (to form a different substance) is a chemical property. This explanation makes option C wrong and option B correct.