Achemical equation is shown: c2h4 + o2 → co2 + h2o according to the law of conservation of mass, how many atoms of oxygen exist in the products of this reaction? 5 6 7 8

C2H4 + O2 → CO2 + H2O

eqn is unbalanced - balancing by counting no. of C n H atoms

C=2 n H=4 in one C2H4

so the reaction will form two CO2 + two H2O

counting no. of O atoms: 2*2 + 2*1

=4+2

=6

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.