Question

Identify the products and write a balanced equation for the reaction of hydrogen with (a) nitrogen; (b) fluorine; (c) cesium; (d) copper(II) ions.

Short answer

The balanced equations are: (a) N2 (g) + 3H2 (g) -> 2NH3 (g), (b) H2 (g) + F2 (g) -> 2HF (g), (c) H2 (g) + 2Cs (s) -> 2CsH (s), (d) H2 (g) + Cu^2+ (aq) -> Cu (s) + 2H^+ (aq).

Step-by-step solution

Identify Product with Nitrogen

When hydrogen reacts with nitrogen, they form ammonia (NH3). The unbalanced equation is: N2 (g) + H2 (g) -> NH3 (g).

Balance the Equation with Nitrogen

To balance the nitrogen atoms, we place a coefficient of 2 in front of NH3, which gives us 2NH3. Now, balance the hydrogen atoms by placing a coefficient of 3 in front of H2, giving us the balanced equation: N2 (g) + 3H2 (g) -> 2NH3 (g).

Identify Product with Fluorine

Hydrogen reacts with fluorine to produce hydrogen fluoride (HF). The unbalanced equation is: H2 (g) + F2 (g) -> HF (g).

Balance the Equation with Fluorine

To balance the fluorine atoms, we put a coefficient of 2 in front of HF. To balance the hydrogen atoms, we put a coefficient of 1 in front of H2. The balanced equation is: H2 (g) + F2 (g) -> 2HF (g).

Identify Product with Cesium

Hydrogen reacts with cesium to produce cesium hydride (CsH). The unbalanced equation is: H2 (g) + Cs (s) -> CsH (s).

Balance the Equation with Cesium

The reaction between hydrogen and cesium is already balanced with one molecule of hydrogen and one atom of cesium producing one molecule of cesium hydride: H2 (g) + 2Cs (s) -> 2CsH (s).

Identify Product with Copper(II) ions

Hydrogen reacts with copper(II) ions to produce copper metal and water (H2O). The unbalanced equation is: H2 (g) + Cu^2+ (aq) -> Cu (s) + H2O (l).

Balance the Equation with Copper(II) ions

To balance the copper atoms, we only need one copper atom on each side. To balance the hydrogen atoms, we make sure there are 2 hydrogens on each side which also naturally balances the oxygen atoms. The number of charges should also be balanced, with zero net charge on both sides. The balanced equation is: H2 (g) + Cu^2+ (aq) -> Cu (s) + 2H^+ (aq).

Key concepts

Chemical Reactions

Chemical reactions are the processes in which substances, known as reactants, transform into new substances called products. During these reactions, bonds between atoms break and new bonds form, which results in different chemical structures. A fundamental aspect of a chemical reaction is that the total mass remains unchanged; that is, matter is neither created nor destroyed in the process known as the Law of Conservation of Mass.

For instance, when hydrogen (H₂) reacts with nitrogen (N₂), ammonia (NH₃) is produced. This reaction is key in the industrial production of fertilizers. Similarly, hydrogen can react with fluorine (F₂), resulting in hydrogen fluoride (HF), which is important in chemical manufacturing. Each reaction varies in complexity and the type of chemical change involved, showcasing the diverse nature of chemical processes.

Stoichiometry

Stoichiometry is a branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions. This involves using the balanced chemical equation to calculate the masses, volumes, or number of moles of substances involved. It's central to various applications, such as calculating yields for reactions or determining the amount of a reactant needed to produce a certain quantity of product.

To apply stoichiometry to a reaction, the equation must be balanced, meaning the number of atoms of each element is the same on both sides of the equation. For example, in the reaction of hydrogen with copper(II) ions, stoichiometry helps to determine the proportions necessary to fully consume both reactants, ensuring that copper metal and water are produced without excess hydrogen or copper ions.

Chemical Equation Balancing

Balancing chemical equations is the process of ensuring that the number of each type of atom is equal on both sides of a chemical equation. A balanced equation adheres to the Law of Conservation of Mass and is vital for correctly understanding how reactants will transform into products.

Each element's atom count must be considered carefully. If hydrogen and cesium are reacting, the balanced equation reflects the one-to-one reaction stoichiometry. The strategy often involves placing coefficients in front of chemical formulas to indicate the number of units of each substance involved. In the balloon example of hydrogen with nitrogen, balancing begins with nitrogen and then adjusts hydrogen, resulting in two molecules of ammonia for every three diatomic hydrogen molecules reacting. The coefficients are the smallest whole numbers that achieve balance, a fundamental principle in obtaining accurate stoichiometric calculations.

Reaction Products

Reaction products are the end result of a chemical reaction and these new substances possess different physical and chemical properties from the original reactants. Identifying products is crucial not only in academic exercises but also in practical applications like material synthesis, environmental engineering, and drug development.

In our examples, hydrogen reacts with different elements to form a variety of products: with nitrogen to produce ammonia, with fluorine to yield hydrogen fluoride, with cesium to generate cesium hydride, and with copper(II) ions to form copper and water. Each product has distinct uses and characteristics. For example, ammonia is widely used in fertilizers, while hydrogen fluoride is essential in industrial chemical processes, emphasizing the significance of understanding reaction products in chemistry.