Which of the following statements is true? metals usually gain electrons to fill their outermost shells. mixtures can be broken apart by physical processes. gelatin powder is dissolved in hot water. gelatin is the solvent. compounds with ionic bonds are difficult to dissolve in water.

Explanation:

When two or more substances mix together but they do not combine chemically with each other then it is known as a mixture.

For example, sand in water is a mixture.

Mixtures can be separated by physical processes like filtration, fraction distillation etc.

Also, when a substance is soluble in another liquid then the substance is known as solute whereas the liquid is known as solvent.

A solute is always present in less quantity as compared to the solvent in a solution.

For example, gelatin powder is dissolved in hot water. Here, gelatin is the solute and hot water is the solvent.

Therefore, we can conclude that the following statements are true.

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.