Find the percent of water in Zn3(PO4)2 x 7H2O

24.66%

Explanation:

To find the percent of water (H2O) in the following compound: Zn3(PO4)2. 7H2O

The atomic mass of the elements are as follows:

Zn = 65g/mol

P = 31g/mol

O = 16g/mol

H = 1g/mol

Hence, molar mass of the compound is as follows:

65(3) + {31 + 16(4)} 2 + 7{1(2) + 16}

195 + 95(2) + 7(18)

195 + 190 + 126

511g/mol

Molar mass of 7H2O

= 7(18)

= 126g/mol

Hence, the percent of H2O in the compound is:

Molar Mass of 7H2O/molar mass of compound × 100

= 126/511 × 100

= 0.2466 × 100

= 24.66%

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.