atoms and molecules Flashcards
what is the law of conservation of mass?
the law of conservation of mass states that mass can neither be created nor destroyed
what is the law of constant proportion?
in chemical substance elements are present in a definite proportion by mass
who stated the law of conservation of mass?
Antoine Lavoisier
who stated the law of constant proportion?
Joseph L. Proust
who was John Dalton
State the postulates of Dalton’s atomic theory
1) every matter is made up of tiny particles called atoms which participate in chemical reactions.
2) atoms are indivisible particles, which cannot be created nor destroyed
3) atoms of the same element have the same mass and chemical properties
4)atoms of different elements have different masses and chemical properties
5)atoms combine in a ratio of small whole numbers to form compounds
6) the relative number and the kinds of atoms are constant in a given compound
which postulate of Dalton’s atomic theory resonate with the law of conservation of mass?
the 2nd postulate
which postulate of Dalton’s atomic theory resonate with law of constant proportion?
6th
drawback of Dalton’s atomic theory?
1) atoms are divisible into protons, neutrons and electrons.
2) atoms of the same element may have different masses. example: Cl-35, Cl- 37
3) atoms of diffrent elements may have same masses.
example: Ca-40 , Ar- 40
what is an atom?
the building blocks of all matter are atoms, they are defined as the smallest particle of an element which may or may not be capable of independent existence
atomic radius is measured in?
nanometers
what is IUPAC
IUPAC ( international union of pure & applied chemistry) is a international scientific organization which approves names of elements units.
