What is a chemical substance?
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A chemical substance is any material substance used in or obtained by a process in chemistry. It can be an element, a compound, or a mixture thereof:\n\nA chemical element is a substance that cannot be divided or changed into different substances by ordinary chemical methods. The smallest particle of such an element is an atom, which consists of electrons centered about an nucleus of protons and neutrons. \nA chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. \nA molecule is the smallest particle of an element or compound that retains the chemical characteristics of the element or compound. \nAn ion is an atom or group of atoms with a net electric charge, having lost (cation) or gained (anion) an electron. \nThe term "chemical" may refer to any chemical substance, though a popular meaning is "a product of the chemical industry". As such the term may carry connotations of being "unnatural" and perhaps harmful, even when such fears are unjustified, as with the dihydrogen monoxide hoax. \nRetrieved
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A chemical reaction is a process that results in the interconversion of chemical substances. The substance(s) initially involved in a chemical reaction are called reactants. Chemical reactions are characterized by a chemical change and it yields one or more product(s) which are different from the reactants.
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Yes you are correct.Different substances are different because of  their molecular structure and the constituents of each molecule. Molecules are well bound together in solids than in fluids (gases and liquids). The molecules are free in gases.\n Further the molecules are not at rest and are in vibrations.When the substance is heated  the average energy of a molecule  increases which tend to decrease the bindings of the molecules.\nGenerally by heating , a substance  chnges from solid to liquid and then to gaseous state.We call this as physical change.\nWhen the energy is  strong enough to break the  molecules into its constituent elements new compounds are produced we call it as chemical change.\nIn effect heat  has many things to do with their bondings
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n chemistry, a physical change is when a substance undergoes some form of change that does not change the substance at the molecular level (i.e. a chemical change). Physical changes do not create new substances, as in a chemical change, but result in the same substance in a different form or shape. A physical change in which a substance changes states between solid, liquid and gas is called a phase change. When water is frozen into ice it undergoes a phase change, and thus a physical change, as it is still water but in a different form. Under normal conditions physical changes can generally be considered reversible, however this does not always hold true. Other characteristics of physical changes include the absence of a newly created substance or the change is reversible.\n\nA chemical change is a process in which reactants are changed into one or more different products. A chemical change occurs whenever new compounds are formed or existing compounds decomposed. During this reaction, chemical bonds between atoms are broken and new chemical bonds formed. This results in a rearrangement of the chemical bonds.\n\nThere are several different types of chemical change. These include synthesis, decomposition, single displacement, double displacement, neutralization, precipitation and redox.\n\nIndicators of a chemical change include a colour change, the formation of a precipitate, the formation of gas, production of heat or light, the appearance of a new substance, a use-up of a starting substance, or exposure to the tertiary chooper enzyme or a change in temperature or energy. When new substances are formed, a chemical change has occurred, and a chemical reaction has taken place.
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First of all, do you know what a molecule is?\n\nA molecule is the smallest particle of a substance (that still has the same chemical and physical properties of the substance) that is composed of 2 or more atoms.  Atoms are held together by a number of chemical forces, including a wide variety of bonds.\n\nAn inorganic molecule is a molecule from a substance that is non-living.  It is not composed of organic (living) matter, and often times that means it will not contain carbon, as carbon (C) is the main element of organic molecules.
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If I remember correctly from my science classes, a mineral is essentially a solid substance that has a crystal structure.  (That's two right there - It's solid, and has to be crystal in structure.)  It also has to be inorganic and occurs naturally, and also homogenous.  Not to mention the fact that it's supposed to have a defined chemical composition.  That's more than four characteristics, but I believe them to be all true of minerals....
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Chemical properties are properties such as boiling point, freezing point, melting point, electronegativity, flammability, and so forth.  Physical properties are the ones the human senses can pick up with out having to change the chemical, such as taste, smell, sound.
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it a chemical combination of two or more atoms of 1 or more elements.\nIt can be a molecule of an element in particuular or it can be a compound molecule.\nMolecule is the form in which the chemical substances usually tend to exist.\nIts characteristics are : \n-it is chemically stable\n-it has definite propperties\nand so on...........
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chemical composition simply means the chemicals which make \nup a molecule  or compound and the amount of each.
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Do you mean a reaction?  Some can be tracked by analytical methods.  Chemical equation has no meaning in this context.
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A solid that is formed by a chemical reaction.
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You really need to be specific here.  Everything is a chemical - the food we eat, the air we breathe, etc.
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Molecules are made of atoms
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An alloy is a combination, either in solution or compound, of two or more elements, which has a combination of at least one metal, and where the resultant material has metallic properties. The result is a metallic substance with properties different from those of its components.\n\nIn chemistry, a physical change is when a substance undergoes some form of change that does not change the substance at the molecular level (i.e. a chemical change). Physical changes do not create new substances, as in a chemical change, but result in the same substance in a different form or shape. A physical change in which a substance changes states between solid, liquid and gas is called a phase change. When water is frozen into ice it undergoes a phase change, and thus a physical change, as it is still water but in a different form. Under normal conditions physical changes can generally be considered reversible, however this does not always hold true.\n\nA chemical change is a process in which reactants are changed into one or more different products. A chemical change occurs whenever new compounds are formed or existing compounds decomposed. During this reaction, chemical bonds between atoms are broken and new chemical bonds formed. This results in a rearrangement of the chemical bonds.\n\nCONCLUSION/ ANSWER to you question!\nThus, brass, an alloy of copper and zinc, will still have individual copper and zince molecules, there is no change at the molecular level. No new compound has been formed. \nSo alloy undergoes PHYSICAL CHANGE!
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Chemistry is about two substances which could react and the resultant does not possess all or some the qualities of the initial substance thus forming a completely a new substance.  Therefore each substance that reacts is a special one, known as an 'element' having a characteristics of its own.  Diffrent elements react among themselves in chemical reaction.\nVR
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Chemistry is the study of the make-up and properties of matter.
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A chemical reaction is material changing from a beginning mass to a resulting substance. The hallmark of a chemical reaction is that new material or materials are made, along with the disappearance of the mass that changed to make the new. This does not mean that new elements have been made. In order to make new elements, the nuclear contents must change. There are magnitudes of difference in the amounts of energy in ordinary chemical reactions compared to nuclear reactions, the rearrangement of the nuclei of atoms to change to new elements is enormous compared to the smaller energies of chemical changes. The alchemists, in their efforts to change less expensive metals to gold, did not have the fundamental understanding of what they were attempting to do to appreciate the difference. \n\nA chemical equation is a way to describe what goes on in a chemical reaction, the actual change in a material. Chemical equations are written with the symbols of materials to include elements, ionic or covalent compounds, aqueous solutions, ions, or particles. There is an arrow pointing to the right that indicates the action of the reaction. The materials to the left of the arrow are the reactants, or materials that are going to react. The materials to the right of the arrow are the products, or materials that have been produced by the reaction. The Law of Conservation of Mass states that in a chemical reaction no mass is lost or gained. The Law of Conservation of Mass applies to individual types of atom. One could say that for any element, there is no loss or gain of that element in a chemical reaction. There are such things as reversible reactions, reactions in which the products reassemble to become the original products. Reversible reactions are symbolized in chemical equations by a double-headed arrow, but the standard remains to call the materials on the left the reactants and the materials on the right the products.