How would I solve this problem? How would I find the Atomic Mass for each isotope?

126.86 amu

Explanation:

You divide each percent abundance by 100 and multiply it by the atomic masses and then add them all up to get the average atomic mass.

(.80 x 127) + (.17 x 126) + (.03 x 128) = 126.86 amu

i believe it is c.) 1575 j.

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.