A compound of C and H consists of 94.34% C and 5.66% H, by mass. The molecular mass of the compound is found to be 178 u. What is its molecular formula? (higher multiplier for this one)

Explanation:

mass ratio of C and H = 94.34 : 5.66

mole ratio of C and H = 94.34 /12 : 5.66 /1

= 7.86 : 5.66

= 1.388 : 1

= 6.94 : 5

or , 7 : 5

So empirical formula = C₇ H₅

Let the molecular formula = ( C₇ H₅)ₙ where n is an integer

Molecular weight = n ( 7 x 12 + 5 x  1 )

89 n = 178

n = 2

mol formula = C₁₄ H₁₀.

a

explanation:

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.