Download
1 / 7
100 likes | 391 Views
Atomic Mass & Molecular Mass. Definition. The average mass of an atom of a specific element. The unit of measure in the AMU or u (atomic mass unit). 1 proton = 1 u 1 neutron = 1 u 1 electron = roughly 1/2000 u; (1/1823). Atomic Mass. Examples. What is the atomic mass of oxygen?
E N D
Definition • The average mass of an atom of a specific element. • The unit of measure in the AMU or u (atomic mass unit). • 1 proton = 1 u • 1 neutron = 1 u • 1 electron = roughly 1/2000 u; (1/1823) Atomic Mass
Examples • What is the atomic mass of oxygen? • 16.0 u (Look at the periodic table) • What is the atomic mass of Boron? • 10.8 u Atomic Mass
Definition • Refers to the average mass of the atoms of an element – all the isotopes combined. • Atoms of an element always have the same number of p+ and e-, but may have different numbers of no (called isotopes). Atomic Mass
Example Atomic Mass 6C12 6C14 Or 12C 14C 6 6 Carbon-12 has 6 p+, 6 e- & 6 no Carbon-14 has 6 p+, 6 e- & 8 no
Example • Find the molecular mass of C4H6O2, (butonedione). • 4 Carbon atoms => 4 x 12.0 = 48.0 u • 6 Hydrogen atoms => 6 x 1.0 = 6.0 u • 2 Oxygen atoms => 2 x 16.0 = 32.0 u • 86.0 u Molecular Mass
Example • Find the molecular mass of Calcium nitrate, Ca(NO3)2. • 1 Calcium atom => 1 x 40.1 = 40.1 u • 2 Nitrogen atoms => 2 x 14.0 = 28.0 u • 6 Oxygen atoms => 6 x 16.0 = 96.0 u • 161.1 u Molecular Mass
