Identify the coefficients and subscripts in the following formulas. If there is not one, write: none – means 1 1) 3MgCl2 coefficient: Subscript for Mg: Subscript for Cl: 2) V2O5 coefficient: Subscript for V: Subscript for 0: 3) 4K2CO3 coefficient: Subscript for K: Subscript for C: Subscript for 0: 4) NaC2H3O2 coefficient: Subscript for Na: Subscript for C: Subscript for H: Subscript for 0:
The Correct Answer and Explanation is:
Section A: Coefficients and Subscripts
- 3MgCl₂
- Coefficient: 3
- Subscript for Mg: 1
- Subscript for Cl: 2
- V₂O₅
- Coefficient: none (means 1)
- Subscript for V: 2
- Subscript for O: 5
- 4K₂CO₃
- Coefficient: 4
- Subscript for K: 2
- Subscript for C: 1
- Subscript for O: 3
- NaC₂H₃O₂
- Coefficient: none (means 1)
- Subscript for Na: 1
- Subscript for C: 2
- Subscript for H: 3
- Subscript for O: 2
Explanation
In chemical formulas, coefficients and subscripts help us understand how many atoms or molecules are involved in a substance or reaction.
Coefficients appear in front of the formula. They show how many molecules or formula units of the compound are present. For example, in 3MgCl₂, the number 3 is the coefficient. This means there are three molecules of magnesium chloride.
Subscripts are the small numbers written after element symbols within a chemical formula. They show the number of atoms of that element in one molecule or unit of the substance. In MgCl₂, the subscript 2 after Cl shows there are two chlorine atoms for every one magnesium atom. Magnesium has no subscript, which means there is only one atom of magnesium (subscript of 1 is implied).
In V₂O₅, there is no number in front, so the coefficient is considered to be 1. The subscripts 2 and 5 show there are two vanadium atoms and five oxygen atoms in one molecule.
In 4K₂CO₃, the coefficient 4 means there are four units of potassium carbonate. The subscripts show two potassium atoms, one carbon atom, and three oxygen atoms in each unit.
In NaC₂H₃O₂, no coefficient is written, so it is 1. The formula contains one sodium atom, two carbon atoms, three hydrogen atoms, and two oxygen atoms. This compound is called sodium acetate, a common salt in chemistry.
Understanding coefficients and subscripts is important for balancing equations and calculating quantities in chemical reactions.
