Question

Give the chemical formula for (a) hydrocyanic acid, (b) nickel tetracarbonyl, (c) barium bicarbonate, (d) calcium acetylide (e) potassium carbonate.

Short answer

(a) HCN (b) Ni(CO)_4 (c) Ba(HCO_3)_2 (d) CaC_2 (e) K_2CO_3

Step-by-step solution

Identify the ions

Hydrocyanic acid consists of hydrogen (H) and cyanide (CN) ions. The hydrogen ion has a charge of +1 and the cyanide ion has a charge of -1.

Write the chemical formula

Since the charges of hydrogen and cyanide ions are of equal magnitude but opposite signs, we can combine one hydrogen ion with one cyanide ion to form a neutral compound. Thus, the chemical formula for hydrocyanic acid is HCN. #b. Nickel tetracarbonyl#

Identify the ions

Nickel tetracarbonyl consists of nickel (Ni) and carbonyl (CO) ions. The nickel ion has a charge of +2 and the carbonyl ion has a charge of -1.

Write the chemical formula

To cancel the charges, we need two carbonyl ions for each nickel ion. Thus, the chemical formula for nickel tetracarbonyl is Ni(CO)_4. #c. Barium bicarbonate#

Identify the ions

Barium bicarbonate consists of barium (Ba) and bicarbonate (HCO_3) ions. The barium ion has a charge of +2 and the bicarbonate ion has a charge of -1.

Write the chemical formula

To cancel the charges, we need two bicarbonate ions for each barium ion. Thus, the chemical formula for barium bicarbonate is Ba(HCO_3)_2. #d. Calcium acetylide#

Identify the ions

Calcium acetylide consists of calcium (Ca) and acetylide (C_2H) ions. The calcium ion has a charge of +2 and the acetylide ion has a charge of -2.

Write the chemical formula

Since the charges of calcium and acetylide ions are of equal magnitude but opposite signs, we can combine one calcium ion with one acetylide ion to form a neutral compound. Thus, the chemical formula for calcium acetylide is CaC_2. #e. Potassium carbonate#

Identify the ions

Potassium carbonate consists of potassium (K) and carbonate (CO_3) ions. The potassium ion has a charge of +1 and the carbonate ion has a charge of -2.

Write the chemical formula

To cancel the charges, we need two potassium ions for each carbonate ion. Thus, the chemical formula for potassium carbonate is K_2CO_3.

Key concepts

Ionic Compounds

Ionic compounds are chemical compounds composed of ions. These ions are atoms or molecules that have net positive or negative charges due to the loss or gain of one or more electrons. In ionic compounds, you find that these ions are bonded together by ionic bonds. They typically form between metals and non-metals where the metal gives away an electron (or electrons) making it more positive, and the non-metal accepts the electron(s) making it more negative.

Some examples of ionic compounds include NaCl (sodium chloride), where sodium (Na) loses an electron and chlorine (Cl) gains an electron. This should help you understand how ionic bonds show up in many chemical formulas.

• Metal and non-metal combination
• Electrons exchanged between atoms
• Structure based on electrostatic attraction

Charge Balancing

When creating chemical formulas for ionic compounds, it's essential to balance the charges. This ensures that the overall charge of the compound is neutral, meaning the sum of positive charges equals the sum of the negative charges.

Here's how you do it: First, identify the charges of the ions involved as shown in the solution steps. For any ionic compound:

• Calculate the total positive charge from the cation(s).
• Calculate the total negative charge from the anion(s).
• Adjust the ratio of ions to ensure the charges balance (net zero charge).

For instance, in calcium acetylide, the charges are +2 for calcium and -2 for acetylide, so the chemical formula is simply CaC_2. The critical goal is always to achieve the zero net charge.

Chemical Nomenclature

Chemical nomenclature is the systematic naming of chemical compounds. This involves following specific linguistic rules set by organizations like IUPAC (International Union of Pure and Applied Chemistry). In essence, it helps us communicate information about the structure of compounds in a standardized way.

For ionic compounds, knowing the names of common ions and recognizing the patterns in naming can be particularly beneficial. For example:

• Cations (positive ions) retain their elemental name, like sodium (Na⁺) or potassium (K⁺).
• Anions (negative ions) often add the suffix -ide, like chloride (Cl^-) or oxide (O^2-).
• Compounds formed include both ion names, such as calcium chloride for CaCl₂.

Grasping the basics of chemical nomenclature facilitates understanding chemical reactions, formulas, and enhances clear scientific communication.