Relative Mass
The relative mass of an object is the comparison of the mass of the object to the mass of a standard object.
Relative Atomic Mass
Relative Atomic Mass
The relative atomic mass (Ar) of an element is the average mass of one atom of the element when compared with 1/12 of the mass of an atom of carbon-12, which taken as 12 units.
- The mass of an atom when compared to another is known as the relative atomic mass (Ar).
- The relative atomic mass (Ar) of an element is the average mass of one atom of the element when compared with 1/12 of the mass of an atom of carbon-12, which taken as 12 units.
- 1/12 of the mass of an atom of carbon-12 is named as 1 atomic mass unit (amu).
- The mass of one carbon atom is 12 amu.
- 1/12 of the mass of an atom of carbon-12 is named as 1 atomic mass unit (amu).
- The mass of one carbon atom is 12 amu.
Example 1
Example 2:
The mass of element A is twice of the mass of carbon, therefore its relative atomic mass is __________. (Relative atomic mass of carbon = 12)
Answer:
Example 3:
An atom of element X is 13 times heavier than one atom of helium. Calculate the relative atomic mass of X.( Ar: He = 4 )
Answer:
Example 4:
How many times that the mass of 2 bromine atoms are greater than 4 neon atoms? (Ar: Ne = 20; Br = 80 )
Answer:
2(80) / 4(20) =2
Example 5
4 atoms of element L have the same mass as 1 tellurium atom. Find the relative atomic mass of L. (Ar: Te = 128 )
4L = 1(128)
L = 128/4 =32