Question

Compare the mass of the reactants and the mass of the products in a chemical reaction, and explain how these masses are related.

Short answer

In a chemical reaction, the mass of the reactants and the mass of the products are related by the Law of Conservation of Mass, which states that the total mass of reactants is equal to the total mass of products in a closed system. This principle is based on the fact that matter can neither be created nor destroyed in a chemical reaction. To compare the masses, one should identify the reactants and products, determine their respective molar masses and total masses, and then verify if the total mass of reactants equals the total mass of products. This relationship is applicable to all chemical reactions and helps verify if a chemical equation is balanced.

Step-by-step solution

Understand the Law of Conservation of Mass

The Law of Conservation of Mass states that the total mass of reactants in a chemical reaction is equal to the total mass of the products. This principle is based on the fact that matter can neither be created nor destroyed in a chemical reaction.

Identify the reactants and products

In a given chemical reaction, the reactants are the substances that undergo a change to form new substances, which are the products. Identify the reactants and products in the reaction equation before you start comparing their masses.

Determine the masses of the reactants and products

For each reactant and product, find their molar masses by looking up the atomic weight of each element in the periodic table and multiplying it by the number of atoms of that element in the molecule. Then, multiply the molar mass of each reactant or product by the respective coefficients in the balanced chemical equation to determine the total mass of reactants and products.

Compare the mass of the reactants and the mass of the products

Now that we have determined the masses of the reactants and products, we can compare them to check if they are equal. If the total mass of reactants equals the total mass of products, it means the Law of Conservation of Mass is upheld in the chemical reaction.

Explain the relationship between the masses of reactants and products

According to the Law of Conservation of Mass, the mass of the reactants is always equal to the mass of the products in a closed system. This principle is applicable to all chemical reactions, and it helps us verify if a chemical equation is balanced. It is important to understand this relationship to analyze and predict the outcomes of various chemical reactions.

Key concepts

Chemical Reaction

A chemical reaction is a process where substances, known as reactants, are transformed into new substances called products. These reactions involve the breaking and forming of chemical bonds. It's like a dance where molecules rearrange to create something new.
Understanding chemical reactions is essential for many scientific fields, such as chemistry, biology, and environmental science. Observing a chemical change involves noting any change in color, gas formation, or temperature.

• The reactions can be endothermic, absorbing heat, or exothermic, releasing heat.
• Reactions are orderly processes that can have varying speeds, influenced by factors like temperature and pressure.

Recognizing a chemical reaction helps establish how substances interact and transform, making this concept fundamental to controlling chemical processes.

Reactants and Products

In any chemical reaction, you'll hear about reactants and products. Reactants are the starting materials, the substances that undergo change during the reaction.
Products, on the other hand, are the outcome, the new substances formed as a result of the reaction.

• Reactants are always on the left side of a chemical equation.
• Products are shown on the right side of the equation.

For instance, if you combine hydrogen (H₂) and oxygen (O₂), and a spark provides the energy, water (H₂O) becomes the product. The transformation from reactants to products involves breaking bonds in reactants and forming new bonds in products. Observing these changes helps chemists understand the intricacies of chemical reactions.

Molar Mass

Molar mass concept allows us to calculate the weight of all reactant and product molecules involved in a chemical reaction. It is expressed in grams per mole and helps ensure that equations adhere to the Law of Conservation of Mass.
To find the molar mass of a compound:

• First, get the atomic weight of each element from the periodic table.
• Multiply the atomic weight by the number of atoms of that element in the compound.
• Add up the weights of each element to get the molar mass of the compound.

For example, water (H₂O) has a molar mass of approximately 18 g/mol, calculated by adding the molar masses of 2 hydrogen atoms and 1 oxygen atom. Molar mass is a key concept to determine the quantity of chemicals involved in reactions and to compare the masses of reactants and products.

Chemical Equation Balancing

Chemical equation balancing is crucial to accurately represent a reaction, making sure that the number of atoms for each element is the same on both sides. This balance is mandatory to comply with the Law of Conservation of Mass. An unbalanced equation doesn't appropriately represent a chemical reaction.
Steps to balance a chemical equation:

• Write down the unbalanced equation.
• Count the number of atoms for each element on both the reactant and product sides.
• Adjust the coefficients, which are numbers placed in front of compounds, to balance the atoms for each element.

For example, the combustion of methane (CH₄) initially might look like this: CH₄ + O₂ → CO₂ + H₂O. Upon balancing, it becomes CH₄ + 2O₂ → CO₂ + 2H₂O. Balancing equations ensures an accurate representation of the chemical processes.