Problem 63 - Chemistry The Central Science In Si Units

Question

Give the chemical formula for (a) copper(II) carbonate, (b) carbon monoxide, (c) magnesium hydrogen carbonate, (d) lithium acetylide, (e) carbon tetrafluoride.

Step-by-Step Solution

Answer

The formulas are (a) CuCO₃, (b) CO, (c) Mg(HCO₃)₂, (d) Li₂C₂, (e) CF₄.

Step 1: Understanding Copper(II) Carbonate

For copper(II) carbonate, the Roman numeral II indicates that copper has a charge of +2, represented as Cu²⁺. The carbonate ion has a charge of -2, represented as CO₃²⁻. To balance the charges, one Cu²⁺ pairs with one CO₃²⁻, resulting in the formula CuCO₃.

Step 2: Understanding Carbon Monoxide

Carbon monoxide is a compound consisting of one carbon atom and one oxygen atom. The formula is straightforward as there are no charges to balance. Therefore, the chemical formula for carbon monoxide is CO.

Step 3: Understanding Magnesium Hydrogen Carbonate

Magnesium has a charge of +2, represented as Mg²⁺. The hydrogen carbonate ion, HCO₃⁻, has a charge of -1. To balance the charges, two HCO₃⁻ ions are needed for each Mg²⁺. Therefore, the formula for magnesium hydrogen carbonate is Mg(HCO₃)₂.

Step 4: Understanding Lithium Acetylide

Lithium has a charge of +1, represented as Li⁺. Acetylide refers to the carbide ion C₂²⁻, where one C₂²⁻ binds with two Li⁺ ions to balance the charges. Thus, the formula for lithium acetylide is Li₂C₂.

Step 5: Understanding Carbon Tetrafluoride

Carbon tetrafluoride consists of one carbon atom and four fluorine atoms. Carbon typically forms four covalent bonds to complete its valence shell, which can be achieved by bonding with four fluorine atoms. Thus, the formula for carbon tetrafluoride is CF₄.

Key Concepts

Copper(II) Carbonate

Copper(II) carbonate is a compound made up of copper and carbonate ions. The Roman numeral in its name, "II," is crucial because it tells us the charge of the copper ion. In this case, copper carries a positive charge of +2, represented as \( \text{Cu}^{2+} \). The carbonate ion, on the other hand, has a negative charge of -2, noted as \( \text{CO}_3^{2-} \).

To figure out the chemical formula for copper(II) carbonate, you need to balance these charges. Since the copper ion's positive charge exactly cancels out the carbonate ion's negative charge, the two combine in a 1:1 ratio. This gives us the chemical formula \( \text{CuCO}_3 \).

Understanding the way these charges interact is key to writing the correct formula. Balancing charges not only ensures that the formula reflects the actual compound but also prevents mistakes in chemical calculations.

Ion Charges

Ion charges determine how elements combine to form compounds. Ions are atoms or molecules that have gained or lost electrons, resulting in a net charge. This charge is positive if electrons are lost, making the ion a cation, or negative if electrons are gained, making it an anion.

• Cations: Positive ions, like \( \text{Cu}^{2+} \) in copper(II) carbonate.
• Anions: Negative ions, such as \( \text{CO}_3^{2-} \).

Charges play a central role in the formation of chemical formulas. For a stable compound, the total positive and negative charges must balance.

For instance, if you have a \( \text{Mg}^{2+} \) ion and need to pair it with hydrogen carbonate ions (\( \text{HCO}_3^- \)), you would need two of these anions to balance the positive charge (\( \text{Mg} (\text{HCO}_3)_2 \)).

By recognizing ion charges and how they pair, you can predict how compounds are formed and correctly determine their chemical formulas.

Balancing Chemical Equations

Balancing chemical equations is a fundamental skill in chemistry. It involves aligning the number of atoms of each element on both sides of an equation. To balance these equations, you'll use coefficients.

• Start by writing the unbalanced equation.
• Identify the number of each type of atom in both reactants and products.
• Adjust coefficients to even out the atom count on both sides.

Consider a simple reaction: the formation of water. The unbalanced equation is\[ \text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O} \]To balance it, notice there are 2 hydrogen atoms in \( \text{H}_2 \) but only one \( \text{O} \) in \( \text{O}_2 \) and 2 in \( \text{H}_2\text{O} \). Add a coefficient of 2 in front of \( \text{H}_2\text{O} \) and \( \text{H}_2 \):\[ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} \]Now, each side of the equation has 4 hydrogen atoms and 2 oxygen atoms, balanced perfectly.Balancing chemical equations ensures that the "Law of Conservation of Mass," which states that matter is neither created nor destroyed in a chemical reaction, holds true.