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Write The Formulas for The Following Compounds Calculator

Reviewed by Calculator Editorial Team

This guide explains how to write chemical formulas for compounds using the IUPAC naming system. The calculator helps you practice writing formulas for different compounds based on their names.

How to Use This Calculator

To use the calculator:

  1. Enter the name of a compound in the input field.
  2. Select the type of compound (binary, ternary, or acid).
  3. Click "Calculate" to see the formula.
  4. Review the formula and check your work against the examples.

The calculator follows standard chemical naming rules and provides the correct formula for each compound.

Rules for Writing Chemical Formulas

Binary Compounds

For binary compounds (compounds with two elements), the formula is written with the metal first, followed by the nonmetal. The charges are balanced to make the compound neutral.

NaCl (sodium chloride) CaO (calcium oxide) Al2O3 (aluminum oxide)

Ternary Compounds

For ternary compounds (compounds with three elements), the metal is first, followed by the nonmetal, and then the polyatomic ion. The charges are balanced to make the compound neutral.

Na2SO4 (sodium sulfate) Ca3(PO4)2 (calcium phosphate) Fe2(SO4)3 (iron(III) sulfate)

Acids

For acids, the formula starts with H (hydrogen) followed by the nonmetal. The charges are balanced to make the compound neutral.

HCl (hydrochloric acid) H2SO4 (sulfuric acid) HNO3 (nitric acid)

Examples of Writing Formulas

Binary Compound Example

Write the formula for magnesium oxide.

MgO (magnesium oxide)

Ternary Compound Example

Write the formula for aluminum sulfate.

Al2(SO4)3 (aluminum sulfate)

Acid Example

Write the formula for phosphoric acid.

H3PO4 (phosphoric acid)

Common Mistakes to Avoid

When writing chemical formulas, avoid these common mistakes:

  • Writing the nonmetal first in binary compounds.
  • Forgetting to balance charges in ternary compounds.
  • Using the wrong charge for polyatomic ions.
  • Omitting the hydrogen in acid formulas.

Double-check your formulas using the calculator to ensure accuracy.

Frequently Asked Questions

What is the difference between a binary and ternary compound?
A binary compound contains two elements, while a ternary compound contains three elements. The formula for a ternary compound includes a polyatomic ion.
How do I balance charges in a ternary compound?
Balance the charges by ensuring the total positive charge equals the total negative charge. Use parentheses to group polyatomic ions and include the correct subscript.
What is the formula for sulfuric acid?
The formula for sulfuric acid is H2SO4. It contains two hydrogen atoms, one sulfur atom, and four oxygen atoms.
How do I write the formula for an acid?
Start with H (hydrogen) followed by the nonmetal. Balance the charges to make the compound neutral. For example, HCl is hydrochloric acid.