A solid white substance A is heated strongly in the absence of air. It decomposes to form a new white substance B and a gas C. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen. Based on these observations, can we determine whether solids A and B and gas C are elements or compounds?

Verified step by step guidance

1. Identify the properties of gas C. Since it has the same properties as the product obtained when carbon is burned in excess oxygen, gas C is likely carbon dioxide (CO₂), which is a compound.
2. Consider the decomposition reaction: A (solid) → B (solid) + C (gas). Since gas C is a compound (CO₂), solid A must be a compound as well, because it decomposes to form a compound.
3. Analyze solid B. Since solid A decomposes into solid B and gas C, and we know gas C is a compound, solid B could be either an element or a compound. Without additional information, we cannot definitively determine the nature of solid B.
4. Understand that elements cannot be decomposed into simpler substances by chemical means. Since solid A decomposes, it cannot be an element; it must be a compound.
5. Conclude that while we can determine that solid A is a compound and gas C is a compound, we cannot definitively determine whether solid B is an element or a compound based solely on the given information.

Key Concepts

Decomposition Reactions

Decomposition reactions occur when a single compound breaks down into two or more products, often requiring heat or other forms of energy. In this scenario, solid A decomposes into substance B and gas C, indicating that A is likely a compound. Understanding this type of reaction is crucial for analyzing the transformation of substances during heating.

Combustion and Products

Combustion is a chemical reaction that typically involves a substance reacting with oxygen to produce heat and light, resulting in products such as carbon dioxide and water. The question states that gas C has properties similar to those produced when carbon burns in excess oxygen, suggesting that C is likely a gaseous product like carbon dioxide, which can help identify the nature of the original substances.

Elements vs. Compounds

Elements are pure substances that cannot be broken down into simpler substances, while compounds are made up of two or more elements chemically bonded together. The ability to determine whether substances A and B are elements or compounds hinges on their behavior during decomposition and combustion, as well as their physical properties, which can provide insights into their chemical identities.