Problem 7 - Chemistry: An Atoms-Focused Approach

Question

In the combination reaction \(\mathrm{A}+2 \mathrm{B} \rightarrow \mathrm{C}, 1.00\) gram of substance \(A\) and 4.00 grams of substance \(B\) are consumed. How many grams of substance C are formed?

Step-by-Step Solution

Answer

Question: In a combination reaction, substance A (1.00 g) reacts with substance B (4.00 g) to form substance C. Calculate the mass of substance C formed during the reaction. Answer: The mass of substance C formed during the reaction is 5.00 grams.

Step 1: Identify the given information and the unknown we're solving for

In the given reaction, we have: - The mass of substance A consumed is 1.00 grams - The mass of substance B consumed is 4.00 grams - The unknown mass of substance C formed

Step 2: Apply the Law of Conservation of Mass

According to the Law of Conservation of Mass, the total mass of the reactants (substance A and substance B) must be equal to the total mass of the products (substance C). So, we have(Mass of A + Mass of B) = Mass of C.

Step 3: Calculate the Mass of Substance C

Now, we can plug in the values for the mass of substance A and substance B, and solve for the mass of substance C: (mass of A) + (mass of B) = mass of C \((1.00\,\text{g}) + (4.00\, \text{g}) = \text{mass of C}\) \(5.00\, \text{g} = \text{mass of C}\) So, the mass of substance C formed is 5.00 grams.

Key Concepts

Combination Reaction

A combination reaction, also known as a synthesis reaction, is a type of chemical reaction where two or more substances combine to form a single product. This is a fundamental concept in chemistry because it helps us understand how different elements or compounds interact to form more complex substances.
In the given exercise, the reaction is described by the equation:

• \( \mathrm{A}+2 \mathrm{B} \rightarrow \mathrm{C} \)

This means that substance A and substance B react together, in a 1:2 molar ratio, to produce a new substance, C.
Combination reactions often release energy in the form of heat or light, which makes them exothermic. Understanding these reactions is essential not only for academic purposes but also for industrial applications where synthesis of compounds is necessary. By comprehending the nature of such reactions, one can predict the formation of products from reactants under given conditions.

Chemical Reaction Stoichiometry

Stoichiometry is the quantitative study of reactants and products in a chemical reaction. It relies on the balanced chemical equation to provide the necessary ratios of substances involved. This means you can exactly calculate how much of a reactant is needed to produce a desired amount of product, or vice versa.
In the combination reaction given in the exercise, the stoichiometric ratio from the balanced equation

• \( \mathrm{A} + 2 \mathrm{B} \rightarrow \mathrm{C} \)

is crucial. It shows that one mole of A reacts with two moles of B to create one mole of C. This information is vital for calculating how much of each reactant is necessary and how much product will form.
When applying stoichiometry, it’s essential to convert all given quantities to moles, use the mole ratio from the balanced equation, and then convert back to the desired units. This ensures precision in calculations and adherence to the law of conservation of mass.

Mass Calculation

Mass calculation in chemical reactions requires applying the Law of Conservation of Mass, which states that in a closed system, the total mass of reactants is equal to the total mass of products. During any chemical reaction, mass is neither created nor destroyed, only transformed.
For the exercise mentioned, to find the mass of substance C formed, we use the following formula:

• \( \text{Mass of A} + \text{Mass of B} = \text{Mass of C} \)

By substituting the given values:

• \( 1.00\, \text{g} + 4.00\, \text{g} = \text{mass of C} \)

we find that the mass of C is 5.00 grams. This demonstrates how to apply the conservation of mass to calculate unknown masses in a chemical reaction. Ensuring that all masses are measured accurately is critical, as any error could lead to incorrect conclusions about the reactants and products involved.