Compound a and compound b react according to the following chemical equation: in which of the following cases will compound a be the limiting reagent? a + 2b-> 2c+d* o 0.5 mol a is combined with 0.3 mol b o 0.5 mol a is combined with 0.6 mol b o 0.2 mol a is combined with 0.3 mol b o 0.3 mol a is combined with 0.8 mol b

0.3 mol A is combined with 0.8 mol B.

Explanation:

Limiting reagent in a chemical reaction is defined as the reagent that is totally consumed when the chemical reaction is complete.

In the reaction:

A + 2B → 2C+D

For a reaction of 1 mole of A, you need two moles of B. That means for any quantity of A you need twice this quantity in B.

Thus, A is limiting reagent when moles of B are higher than twice moles of A.

* 0.5 mol A is combined with 0.3 mol B. Twice moles of A are 1.0 moles that are higher than 0.3 moles. A is not limitng reagent.

* 0.5 mol A is combined with 0.6 mol B. Twice moles of A are 1.0 moles that are higher than 0.6 moles. A is not limitng reagent.

* 0.2 mol A is combined with 0.3 mol B. Twice moles of A are 0.4 moles that are higher than 0.3 moles. A is not limitng reagent.

* 0.3 mol A is combined with 0.8 mol B. Twice moles of A are 0.6 moles that are lower than 0.8 moles. A IS limitng reagent.

I hope it helps!

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.