Answer:
0.808 M
Explanation:
Using Raoult's Law
where:
= vapor pressure of sea water( solution) = 23.09 mmHg
= vapor pressure of pure water (solute) = 23.76 mmHg
= mole fraction of water
∴
------ equation (1)
------ equation (2)
where; 
number of moles of sea water
number of moles of pure water
equating above equation 1 and 2; we have :
NOW, Molarity = 
As we assume that the sea water contains only NaCl, if NaCl dissociates to Na⁺ and Cl⁻; we have 
Answer:
four elements
Explanation:
He = 1s²
Be = 1s² 2s²
C = 1s² 2s² 2p²
Mg = 1s² 2s² 2p⁶ 3s²
Si = 1s² 2s² 2p⁶ 3s² 3p²
Ca = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
Valence electrons are those electrons which are present in outer most electronic shell.
He, Be, Mg, Ca these four elements have 2 valence electrons.
While Si and C have four valance electrons.
