Question

In 1912, chemist Fritz Haber developed a process that combined nitrogen from the air with hydrogen at high temperatures and pressures to make ammonia. Specifically, the process involved combining one molecule of nitrogen gas (N2) with three molecules of hydrogen gas (H2) to get two molecules of ammonia (NH3). If you write this process in a symbol format, it looks like this:

N2 + 3H2 → 2NH3

Explain whether this is a chemical or physical change, and why. Does it involve elements, compounds, mixtures, or pure substances? Also describe how many atoms are involved before and after. What do you notice about the number of atoms?

Answer 1

Chemical change

Compounds

Number of atoms of hydrogen on both side=6

Number of atoms of nitrogen on both sides=2

Number of atoms of nitrogen and hydrogen on both sides are equal.

Step-by-step explanation:

We are given that a reaction

`N_2+3H_2\rightarrow 2NH_3`

It is chemical change because there is chemical reaction occurring .In physical change, no chemical reaction takes place.

It involved compound because compound consist of two or more than two atoms of same or different elements . In compound , the atoms are bonded together by chemical bond.

Nitrogen is a compound because two nitrogen atoms are bonded together to form a molecule of nitrogen.Similarly , in hydrogen molecules, two hydrogen atom are bonded together to form one hydrogen molecule.

In ammonia, 3 hydrogen and 1 nitrogen atom are bonded together to form ammonia.

On LHS

Number of atoms of hydrogen=6

Number of nitrogen atoms=2

On RHS

Number of atoms of Hydrogen=6

Number of nitrogen atoms=2

Number of atoms of every element in reactants equals to number of atoms of every element in product.

Answer 2

1. This is a chemical change because a chemical reaction has occurred. The material before the reaction is not anymore the same after the reaction.

2. In this reaction, it involves pure substances in the form of elements. These are the nitrogen and the hydrogen elements. The resulting product is also a pure substance in the form of a compound, which is ammonia.

3. Before the reaction, there are 2 atoms of nitrogen and 6 atoms of hydrogen involved. After the reaction, there are also 2 atoms of nitrogen and 6 atoms of hydrogen involved.

4. The number of atoms before and after the reaction did not change because of the Law of Conservation of Mass.