Question

A substance breaks down into its component elements when it is heated. If 68.0 g of the substance is present before it is heated, what is the combined mass of the component elements after heating?

Short answer

The combined mass of the component elements after heating is \(68.0 g\), as the mass is conserved during the reaction according to the law of conservation of mass.

Step-by-step solution

Identifying the given information

We are given the initial mass of the substance, which is 68.0 g.

Applying the law of conservation of mass

According to the law of conservation of mass, the total mass of the component elements after heating should be equal to the mass of the substance before heating.

Finding the combined mass of the component elements after heating

Since the mass is conserved, the combined mass of the component elements after heating is the same as the mass of the substance before heating. Therefore, the combined mass of the component elements after heating is 68.0 g.

Result

The combined mass of the component elements after heating is 68.0 g.

Key concepts

Chemical Decomposition

Chemical decomposition occurs when a compound breaks down into its simpler component elements. This breakdown happens through a chemical reaction, often induced by heating or the presence of a catalyst.
During decomposition:

• The original substance changes, splitting into different substances or elements.
• The process requires energy, most commonly in the form of heat, to break the bonds holding the elements together.
• This reaction is crucial for many industrial and laboratory processes, such as the breakdown of water into hydrogen and oxygen.

Understanding this process helps in manipulating and predicting chemical behavior, which is essential in both scientific research and practical applications. In the context of the given exercise, heating the substance causes it to decompose into its basic elements.

Mass Measurement

Mass measurement is the process of determining the amount of matter in an object, usually expressed in grams or kilograms. Accurate mass measurements are critical in both chemical reactions and everyday applications.
Key points about mass measurement include:

• The use of a balance to measure the mass of substances prior to and after chemical reactions.
• The need for precision and accuracy to ensure reliable experiment outcomes.
• Following standard procedures and calibrating measurement tools regularly to maintain accuracy.

In our exercise, the initial mass of the substance was measured at 68.0 g. This measurement becomes the benchmark for assessing the conservation of mass after heating.

Component Elements

Component elements are the simpler substances that a compound is broken down into during a chemical reaction. These are fundamental chemical entities like atoms or ions, and they cannot be decomposed further using ordinary chemical means.
Understanding component elements entails:

• Recognizing that they are the simplest forms of matter involved in chemical reactions.
• Realizing that they are the building blocks of all substances, emphasizing their significance in chemistry.
• Identifying these elements post-reaction to understand the compound's original structure.

In the scenario described, heating the substance breaks it down into its component elements, while the total mass of these elements remains unchanged due to the conservation of mass. Identifying these components allows chemists to deduce the make-up of the original substance.