That is a very complicated question, and perhaps someone more experienced can answer this better than I.
I will do my best till then. Elements are composed of electrons neutrons and protons. Our star is the mostly in the forth state of mater, plasma and therefore is very hot, it is also very large and that makes it very dense, this creates a lot of heat and energy, far more than we have ever created in total in our lifetimes is expended each second by our star.
It is the massive pressures (squeezing) the atoms tighter together, the heat making them move faster and faster, It is because of all of this energy pressure heat and speed that atoms collide here. This is a constant nuclear reaction held back from running away only because gravity keeps it in check.
I think this is is all necessary to answer you, because it takes this nuclear reaction to create the elements we can see.
We see these elements because of the same effect that make lasers work. In this case it takes the tremendous heat and pressures of our star to excite the electrons of elements into higher orbits. When they fall back to their ground state, like a laser pointer emit a photon that we can detect with and instrument. Like a fingerprint all elements have a unique photon signal.
They put different chemicals into flames and see what color it becomes. Then they can tell for example if a star is made of calcium chloride if the star is green.
The use sonars, radars, satellites, and temperature to determine the composition of a planet.
A chemical change involve a change of composition.
mixture
Several chemical properties can be estimated knowing the chemical composition.
You think probable to a chemical compound. But today the theory of the fixed composition is not generally valid.
substance! (:
A chemical change involve a change of composition.
partially
Chemistry is the scientific study of the composition structure and properties of matter and the changes that it undergoes.
Chemistry is the name of the science which studies composition, matter and structure.Specifically, the science in question deals with matter - elements which have mass and weight - and substances. It emphasizes the composition and properties of matter and substance. It also examines structure.
Chemistry
a mixture
mixture
Matter with a definite composition is a pure substance, such as an element, molecule, molecular compound, or ionic compound.
following the scientist method. it is the same no matter who is doing it.
composition
the juice that comes out of the stem when you squeeze it. Gross composition in plants is the overall matter in it. It is composed of the percent water, dry matter, inorganic and organic matter.
Several chemical properties can be estimated knowing the chemical composition.