When a solution of potassium iodide is added to acidified potassium dichromate, a colour change of orange to green is observed.
Write the redox half-equations and hence the balanced redox equation for the reaction taking place.

It's a redox equation in which potassium iodide(KI) is being oxidized to Iodine (I2) while potassium dichromate is reduced to Chromium (III) (Cr3+) and such we have to first break them into two half reactions. One for the substance being oxidized and the other for that which is being reduced.

Explanation:

Going straight to the half reactions:

2KI = 2K(+) + I2 + 2e-

and

K2Cr2O7 + 14H(+) + 6e- = 2K(+) + 2Cr3(+) + 7H20

Inspecting the two equations above, we see that the electrons produced by KI during oxidation is 2 while that produced by K2Cr2O7 is 6.

We have to make them equal. Therefore, we multiply each term in the oxidation equation by 3.

We have:

6KI = 6K(+) + 3 I2 + 6e-

For the reduction equation, the 14H(+) has to be broken down due to the fact that this was mixed in a sulphuric acid (H2SO4).

With that in mind, rebalancing the reduction equation, we have:

K2Cr2O7 + 7H2SO4 + 6e- = 2K(+) + 2Cr3(+) + 7H20 + 7SO4(2-)

Now, we add the new oxidation and reduction equations together to get:

6KI + K2Cr2O7 + 7H2SO4 + 6e- = 8K(+) + 3I2 + 6e(-) + 2Cr3(+) + 7H20 + 7SO4(2-)

Simplifying it, the 6e- cancels each other to give us:

6KI + K2Cr2O7 + 7H2SO4 = 8K(+) + 3 I2 + 2Cr3(+) + 7H20 + 7SO4(2-)

Now Simplifying further, the SO4(2-) is going to act as a counter ion for the K(+) and Cr(3+).

Therefore,we now have the balanced redox equation as:

6KI + K2Cr2O7 + 7H2SO4 = 4K2SO4 + 3 I2 + Cr2SO4(3) + 7H20

your parents i think this could be it

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .