Chemistry - Online Test

Calcium is a silvery-white metal; it is relatively soft, but much harder than sodium metal.  Calcium is a member of the alkaline-earth metals (Group II on the periodic table); these metals react vigorously with water, although not as violently as the Group I metals such as sodium or potassium:

Ca(s)  +  2H2O(l)  ——>  Ca(OH)2(aq)  +  H2(g)

Molar mass of    Ag NO3  

 =    [  atomic mass of Ag     +  atomic mass of  N   +   3  (   atomic mass of O ) ) ]  u

Substituting the atomic masses of  Ag ,  N   &  O  as   107.9 , 14  &  16  ,respectively in the above expression  we get -  

  =  [107.9+14+(3X16)]$$

=169.9 u

Max Planck theorized that energy was transferred in chunks known as quanta, equal to hν. The variable h is a constant equal to 6.63 × 10-34 J·s and the variable ν$\nu$represents the frequency in 1/s.

This equation allows us to calculate the energy of photons, given their frequency.

If the wavelength is given, the energy can be determined by first using the wave equation(c=λ×ν)to find the frequency, then using Planck’s equation to calculate energy.