They're called allotropes.
tor or more different substance
A substance is considered more soluble in water if it dissolves easily and forms a homogeneous mixture with water. Factors like polarity, molecular size, and temperature can influence solubility in water. Generally, substances that are polar or ionic tend to be more soluble in water compared to nonpolar substances.
A compound is the pure substance formed from the chemical combination of two or more different elements.
In thermodynamics, a pure substance is a substance that has a constant chemical composition and uniform properties throughout. Examples include water, nitrogen, and oxygen. These substances can exist in multiple phases (solid, liquid, gas) and have characteristic phase change behavior under different conditions.
sugar is complicated as it is an organic compound with many different monomer and dimer forms. if your sugar is pure it is not a mixture but if your sugar contains two or more of these forms it is a mixture. I cannot get more precise without more information than is given in your question.
Chemical change forms a new substance from another substance.
Allotropes are two or more different molecular forms of the same element in the same physical state. Examples include diamond and graphite, which are both allotropes of carbon.
Substance B may be more viscous than substance A due to a higher molecular weight, stronger intermolecular forces, or a more complex molecular structure. These factors can lead to increased resistance to flow and greater internal friction within the substance, resulting in higher viscosity.
Carbon forms more compounds than any other element on the Periodic Table, which is why it is key to the substance Vantablack. Carbon's ability to form diverse molecular structures makes it essential to countless organic compounds in nature.
A pure substance made of two or more elements is a compound.
The structure
chemical change.
Nothing different from before they were mixed. It forms an equilibrium.
As a substance transitions from liquid to gas, the molecular motion increases. In the liquid state, molecules move more freely but are still close together. When the substance becomes a gas, the molecules move even more rapidly and are much farther apart.
compound
When atoms are separated the substance changes forms. Solid Liquid Gas Plasma These are a few of the forms. The substance becomes more fluid, more easily shaped and compressed. It is able to form new materials, and is easier to ignite.
The relationship between molecular weight and density in a substance is that generally, substances with higher molecular weights tend to have higher densities. This is because heavier molecules are more tightly packed together, leading to a higher mass per unit volume, which results in a higher density.