The relative mass of an object is the comparison of the mass of the object to the mass of a standard object.
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 element A is twice of the mass of carbon, therefore its relative atomic mass is __________. (Relative atomic mass of carbon = 12)
An atom of element X is 13 times heavier than one atom of helium. Calculate the relative atomic mass of X.( Ar: He = 4 )
How many times that the mass of 2 bromine atoms are greater than 4 neon atoms? (Ar: Ne = 20; Br = 80 )
2(80) / 4(20) =2
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
The relative molecular mass (Mr) of an element is the average mass of one molecule of the element/compound when compared with the mass of an atom of carbon-12, which taken as 12 units.
The relative molecular mass of a molecule is equal to the sum of the relative atomic mass of all the atoms in the molecule.
Find the relative molecular mass of carbon dioxide.
[ JAR: C = 12; O = 16 ]
The formula of carbon dioxide = CO2
Relative molecular mass of CO2 = 1 x 12 + 2 x 16 = 44
Relative molecular mass of Al2(SO4)3
= 2 x 27 + 3( 32 + 4 x 16) = 342