A substance you can't physically change would be copper grains, and iron filings.
A compound is a substance formed by the chemical combination of two or more elements in fixed proportions. A solution is a homogeneous mixture of two or more substances where one substance (solute) is dissolved in another substance (solvent).
I believe that we call matter that can no longer be separated into unique parts an atom. You cannot get any smaller than an atom and still have a recognizable substance. We can separate molecules into individual atoms. Elements consist of the same type of atom (i.e. gold is an element because it consists entirely of the atoms with the same number of protons and neutrons).
An example of a substance that cannot be separated into simpler substances by physical or chemical means is an element like gold or oxygen. Elements are made up of only one type of atom, so they cannot be broken down further by ordinary methods.
The components of a pure substance cannot be separated because they are chemically bonded together in a specific ratio. Any attempt to separate them would require breaking these bonds, which would result in creating new substances. This is different from a mixture, where the components are physically mixed and can be separated through physical means.
molecules
A substance that cannot be separated physically is a pure substance.
If a substance can be physically separated into its components, it is a mixture, not a pure substance. A pure substance consists of only one type of particle and cannot be separated into other substances by physical means.
An element or compound that cannot be physically separated is an atom. Atoms are the smallest unit of matter that retains the properties of an element and cannot be further broken down by physical means. Compounds, on the other hand, can be separated into their individual elements through chemical reactions.
The substance is a compound, which forms chemical bonds that cannot be physically separated, but only by a chemical change.
Elements
A compound, such as water (H2O), cannot be physically separated into its component elements (hydrogen and oxygen) but can be chemically separated through a chemical reaction, such as electrolysis, which breaks the bonds between the elements.
Sugar
A compound is a substance formed by the chemical combination of two or more elements in fixed proportions. A solution is a homogeneous mixture of two or more substances where one substance (solute) is dissolved in another substance (solvent).
A substance that is chemically combined cannot be separated physically.In some situations, you can and can't separate combined substances physically. For example, you can separate sand from rocks physically, but you cannot separate water and ice cream, even though the substances did not undergo a chemical change, because the water soaked into the ice cream.
I believe that we call matter that can no longer be separated into unique parts an atom. You cannot get any smaller than an atom and still have a recognizable substance. We can separate molecules into individual atoms. Elements consist of the same type of atom (i.e. gold is an element because it consists entirely of the atoms with the same number of protons and neutrons).
A pure substance.
An example of a substance that cannot be separated into simpler substances by physical or chemical means is an element like gold or oxygen. Elements are made up of only one type of atom, so they cannot be broken down further by ordinary methods.