Write chemical equations for the reaction of potassium with the following substances, ensuring that the numbers and kinds of atoms are the same on both sides of the equations. If no reaction occurs, write N.R. (b) Br₂ (c) O₂

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Identify the reactants and products for the reaction of potassium (K) with bromine (Br₂). Potassium is a metal and bromine is a halogen, so they will form an ionic compound, potassium bromide (KBr).

Write the balanced chemical equation for the reaction between potassium and bromine. Start by writing the unbalanced equation: K + Br₂ → KBr.

Balance the equation by ensuring the number of each type of atom is the same on both sides. Potassium and bromine form a 1:1 ratio in KBr, but Br₂ means there are two bromine atoms, so you need two KBr to balance the bromine atoms.

For the reaction of potassium with oxygen (O₂), identify the products. Potassium reacts with oxygen to form potassium oxide (K₂O).

Write and balance the chemical equation for the reaction between potassium and oxygen. Start with the unbalanced equation: K + O₂ → K₂O. Balance the equation by ensuring the number of each type of atom is the same on both sides.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Balancing Chemical Equations

Balancing chemical equations is the process of ensuring that the number of atoms for each element is the same on both the reactant and product sides of the equation. This is based on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Each side of the equation must have equal numbers of each type of atom, which often requires adjusting coefficients in front of the chemical formulas.

Reactivity of Potassium

Potassium is an alkali metal known for its high reactivity, particularly with halogens and oxygen. When potassium reacts with halogens like bromine (Br₂), it typically forms a metal halide, such as potassium bromide (KBr). Its reaction with oxygen can produce potassium oxide (K₂O). Understanding the reactivity of potassium helps predict the products of these reactions.

Types of Chemical Reactions

Chemical reactions can be classified into several types, including synthesis, decomposition, single replacement, and double replacement reactions. The reaction of potassium with bromine is an example of a synthesis reaction, where two or more reactants combine to form a single product. Recognizing the type of reaction is essential for predicting the products and writing balanced equations.

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Common Types of Alkane Reactions

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Textbook Question

Which element will react most vigorously with water, and what is the reaction that occurs?

(a) Lithium; 2 Li(s) + 2 H₂O(l) → 2 Li⁺(aq) + 2 H^–(aq) + H₂O₂(aq)

(b) Potassium; 2 K(s) + 2 H₂O(l) → 2 K⁺(aq) + 2 OH^–(aq) + H₂(g)

(d) Barium; Ba(s) + 2 H₂O(l) → Ba²⁺(aq) + 2 H^–(aq) + H₂O₂(aq)

Textbook Question

Consider the following oxoacids: HClO, HClO₂, HClO₃, and HClO₄. In which oxoacid does chlorine have an oxidation state of +5? Which oxoacid is the strongest?

(LO 22.17)

(a) HClO has a Cl oxidation state of +5, and HClO₄ is the strongest acid.

(b) HClO₂ has a Cl oxidation state of +5, and HClO is the strongest acid.

(d) HClO₄ has a Cl oxidation state of +5, and HClO is the strongest acid.