Question

An element \(\mathrm{X}\) reacts with oxygen to form \(\mathrm{XO}_{2}\) and with chlorine to form \(\mathrm{XCl}_{4} . \mathrm{XO}_{2}\) is a white solid that melts at high temperatures (above \(1000^{\circ} \mathrm{C} ) .\) Under usual conditions, \(\mathrm{XCl}_{4}\) is a colorless liquid with a boiling point of \(58^{\circ} \mathrm{C}\) . (a) \(\mathrm{XCl}_{4}\) reacts with water to form \(\mathrm{XO}_{2}\) and another product. What is the likely identity of the other product? (b) Do you think that element \(\mathrm{X}\) is a metal, nonmetal, or metalloid? (c) By using a sourcebook such as the CRC Handbook of Chemistry and Physics, try to determine the identity of element \(\mathrm{X}\).

Short answer

(a) The other product formed when \(\mathrm{XCl}_{4}\) reacts with water is Hydrogen chloride \(\mathrm{(HCl)}\). (b) Element X is most likely a nonmetal, as it forms covalent compounds with Oxygen and Chlorine. (c) Element X is most likely Silicon (Si), as the compounds \(\mathrm{SiO}_{2}\) and \(\mathrm{SiCl}_{4}\) have properties that match the given information.

Step-by-step solution

Determine the other product formed

When \(\mathrm{XCl}_{4}\) reacts with water, it forms \(\mathrm{XO}_{2}\) and another product. We'll focus on the elements we have in the reaction to figure out the other product. We know that \(\mathrm{XCl}_{4}\) has the elements X and Chlorine in it, and it reacts with water, which contains Hydrogen and Oxygen elements. Since \(\mathrm{XO}_{2}\) is one of the products and it has X and Oxygen in it, the other product is likely to contain Hydrogen and Chlorine elements. The most common compound formed by Hydrogen and Chlorine is Hydrogen chloride \(\mathrm{(HCl)}\).

Determine if element X is a metal, nonmetal or metalloid

We are given some physical properties of the compounds formed by element X. \(\mathrm{XO}_{2}\) is a white solid which melts at high temperatures (> \(1000^{\circ} \mathrm{C}\)), and \(\mathrm{XCl}_{4}\) is a colorless liquid with a boiling point of \(58^{\circ} \mathrm{C}\). Considering the type of compounds formed, \(\mathrm{XO}_{2}\) and \(\mathrm{XCl}_{4}\), it seems that element X has properties similar to a nonmetal. This is because nonmetals typically form covalent compounds by sharing electrons with other nonmetals (like Oxygen and Chlorine).

Identify element X

To identify element X, we can compare the properties of the compounds mentioned with known elements and their compounds. One possible way to do this is by using a sourcebook such as the CRC Handbook of Chemistry and Physics. However, we can also use the given properties as a clue: \(\mathrm{XO}_{2}\) has Oxygen as its anion, so we need to search for a nonmetal element in Periodic Table which forms \(\mathrm{XO}_{2}\) compounds by sharing electrons (covalent bonds). One such element is Silicon (Si), which forms Silicon dioxide (\(\mathrm{SiO}_{2}\)). Silicon dioxide is a white solid with a high melting point (around \(1700^{\circ} \mathrm{C}\)). Additionally, Silicon forms Silicon tetrachloride (\(\mathrm{SiCl}_{4}\)), which is a colorless liquid with a boiling point of \(57.6^{\circ} \mathrm{C}\). Considering these properties, we can conclude that element \(\mathrm{X}\) is most likely Silicon (Si).

Key concepts

Element Reaction with Oxygen

Understanding how elements react with oxygen is fundamental in the study of chemistry. Typically, when elements react with oxygen, they form oxides. The type of oxide formed can tell us a lot about the nature of the element itself. For instance, metals tend to form basic oxides, whereas nonmetals often form acidic or neutral oxides. In our exercise, the element X reacts with oxygen to form XO₂, which is a white solid that melts at high temperatures, characteristics often associated with non-metal oxides like silicon dioxide (SiO₂). The high melting point indicates strong bonds within the lattice structure of the oxide, suggesting that element X likely has a giant covalent structure similar to that of silicon in its oxide form. This information is crucial in providing a hint towards the identity of element X.

In a broader educational context, students should be encouraged to think about the implications of such a reaction. For example, the reaction of an element with oxygen can influence the element's properties, applications, and even its behavior in environmental contexts, such as corrosion or combustion processes. Learning to predict these outcomes is a vital skill in chemistry.

Element Reaction with Chlorine

The reaction of elements with chlorine is another key concept to understand as it provides insights into the chemical behavior of an element. When an element reacts with chlorine, it typically forms a chloride. Chlorides can be ionic or covalent compounds, and by examining their physical properties, we can deduce much about the bonding and structure of the element in question. In this case, the element X reacts with chlorine to form XCl₄, a colorless liquid with a boiling point of 58°C. This suggests that the bonds within the compound are covalent as chlorides of nonmetals form such bonds.

Talking about the broad chemical implications, why do we care about an element's reaction with chlorine? Understanding this type of reaction is essential for industrial chemistry applications, including the production of polymers, solvents, and other chemicals. It also plays a role in environmental chemistry, where chlorine compounds can be significant pollutants or useful disinfectants. Students should appreciate that learning the reaction behaviors of chlorine not only applies to theoretical exercises but also to real-world applications that affect industries and ecosystems.

Predicting Chemical Products

Predicting chemical products is a critical skill in chemistry that allows students to anticipate and understand the outcomes of chemical reactions. When predicting the products of a reaction, one must consider the reactivity of the elements involved, their electron configurations, and the types of bonds they typically form. In our exercise, we see that XCl₄ reacts with water, producing XO₂ and another product. Using deduction, we predict that the other product is HCl, since water contributes the hydrogen and XCl₄ provides the chlorine.

This approach is a simplified version of the more complex investigations that chemists perform when determining reaction products. They may use principles such as the conservation of mass, the octet rule, and known reactivity patterns of elements. Being able to predict chemical products is essential, not just academically but also in practical scenarios such as synthesizing new compounds, determining reaction pathways, and even in hazard assessment where predicting the formation of toxic substances is critical for safety.