Which of the following is true of a heterogeneous mixture?
a. different samples may not be exactly alike.
b. the density is the same throughout the entire mixture.
c. it is not possible to separate the various parts of the mixture.
d. taking one sample will enable you to determine what it is made of.

Option (a) is the correct answer.

Explanation:

A heterogeneous mixture is defined as the mixture in which distribution of solvent particles is uneven throughout the solution.

For example, a mixture of sand and water is a heterogeneous mixture.

So, when we take different samples for the same heterogeneous mixture then there will be different composition of solute particles in each of them.

On the other hand, in a homogeneous solution there will be even distribution of solute particles into the solvent. Each sample of a homogeneous mixture will contain same composition of solute particles.

Thus, we can conclude that the statement different samples may not be exactly alike,  is true of a heterogeneous mixture.

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.