4) Calculate the percentage by
mass of oxygen in Pb(NO3)2
A) 193
B20
145

  im getting 331.23

Explanation:

ElementNumberMassPercet Composition

O            6         16.00  28.9828819853274

N             2         14.018.45937867946744

Pb             1        207.2162.5577393352051

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.