Question

Write the formula for each of the following acids and bases: a. magnesium hydroxide b. hydrofluoric acid c. phosphoric acid d. lithium hydroxide e. ammonium hydroxide f. sulfuric acid

Short answer

a. Mg(OH)_2, b. HF, c. H_3PO_4, d. LiOH, e. NH_4OH, f. H_2SO_4

Step-by-step solution

- Understanding Magnesium Hydroxide

Magnesium hydroxide is a base formed from magnesium ions (Mg^{2+}) and hydroxide ions (OH^{-}). The chemical formula is determined by balancing the charges: hydroxide has a charge of -1, so we need two hydroxide ions to balance the +2 charge of magnesium. The formula is Mg(OH)_2.

- Writing Hydrofluoric Acid Formula

Hydrofluoric acid is formed from hydrogen ions (H^{+}) and fluoride ions (F^{-}). Since the charges are equal and opposite, one hydrogen ion pairs with one fluoride ion. The formula is HF.

- Writing Phosphoric Acid Formula

Phosphoric acid contains three hydrogen ions (H^{+}) and one phosphate ion (PO_4^{3-}). The chemical formula is obtained by balancing the charges: three hydrogen ions are needed to balance the -3 charge of phosphate. The formula is H_3PO_4.

- Understanding Lithium Hydroxide

Lithium hydroxide is a base formed from lithium ions (Li^{+}) and hydroxide ions (OH^{-}). Since the charges are equal and opposite, one lithium ion pairs with one hydroxide ion. The formula is LiOH.

- Writing Ammonium Hydroxide Formula

Ammonium hydroxide is formed from ammonium ions (NH_4^{+}) and hydroxide ions (OH^{-}). Since the charges are equal and opposite, one ammonium ion pairs with one hydroxide ion. The formula is NH_4OH.

- Understanding Sulfuric Acid

Sulfuric acid contains two hydrogen ions (H^{+}) and one sulfate ion (SO_4^{2-}). The chemical formula is derived by balancing the charges: two hydrogen ions balance the -2 charge of sulfate. The formula is H_2SO_4.

Key concepts

chemical formulas

Understanding chemical formulas is fundamental in chemistry. A chemical formula represents the elements present in a compound and the ratio in which the atoms of these elements combine. For acids and bases:

• A chemical formula consists of the symbols of the elements involved.
• Subscripts indicate the number of each type of atom in the compound.
• No subscript means one atom of that element.

For example, in the formula for sulfuric acid, H₂SO₄ means there are two hydrogen atoms (H), one sulfur atom (S), and four oxygen atoms (O) in each molecule of sulfuric acid.

acid-base chemistry

Acid-base chemistry studies substances that release hydrogen ions (H⁺) or hydroxide ions (OH^-) in solution.

• Acids typically release hydrogen ions when dissolved in water. For instance, hydrofluoric acid (HF) releases H⁺ and F^- in water.
• Bases typically release hydroxide ions when dissolved in water. Magnesium hydroxide (Mg(OH)₂) releases Mg²⁺ and OH^- ions.

The strength of an acid or base is determined by how completely it dissociates in water. Strong acids and bases dissociate completely, whereas weak acids and bases do not.

ionic compounds

Ionic compounds are formed by the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions).
In acid-base compounds:

• Acids often contain hydrogen ions (H⁺) paired with anions. For example, sulfuric acid (H₂SO₄) contains H⁺ ions and sulfate ions (SO₄^2-).
• Bases often contain hydroxide ions (OH^-) paired with cations. Lithium hydroxide (LiOH) contains Li⁺ ions and OH^- ions.

Ionic compounds have high melting and boiling points due to the strong electrostatic forces between the ions.

charge balancing

Charge balancing is crucial when writing chemical formulas for acids and bases. The total positive charge must equal the total negative charge.

Here’s how to balance charges:

• Identify the charges of the ions. For example, the hydroxide ion (OH^-) has a -1 charge, and the magnesium ion (Mg²⁺) has a +2 charge.
• Balance the charges by adjusting the number of ions. Magnesium hydroxide, Mg(OH)₂, requires two OH^- ions to balance one Mg²⁺ ion.

Always ensure the net charge of the compound is zero.

common acids and bases

Knowing the common acids and bases is essential in chemistry. Here are a few:

• Hydrofluoric acid (HF) is a weak acid used in etching glass.
• Phosphoric acid (H₃PO₄) is used in fertilizers and soft drinks.
• Magnesium hydroxide (Mg(OH)₂) is a base found in milk of magnesia, a common antacid.
• Lithium hydroxide (LiOH) is used in lithium batteries and as a CO₂ scrubber.
• Ammonium hydroxide (NH₄OH) is utilized in household cleaners.
• Sulfuric acid (H₂SO₄) is a strong acid used in car batteries and industrial processes.

Familiarity with these compounds and their formulas is beneficial for many chemical applications.