The chemical properties of a substance can only be observed when it is changed into a different substance t f

Is it true

Explanation:

A chemical property of a substance is evident when it undergoes into a chemical change (that means change into a different substance), because can release or absrob heat, can be visible by some bubble, change in color, etc.

Some examples of chemical properties are the reactivity of a substance, the toxicity, the flammability, the heat of combustion among others.

at the bottom

explanation:

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.