Agreement of Spanish adjectives

In Spanish, the adjectives must agree with the masculine or feminine property of the corresponding nouns. Following are some rules.

1. Spanish adjectives ending in -o change -o to -a when describing a feminine noun:
   (masculino) El papel es blanco. (The paper is white.)
   (femenino) La tiza es blanca. (The chalk is white.)
   
   (masculino) El libro es amarillo. (The book is yellow.)
   (femenino) La flor es amarilla. (The flower is yellow.)
    
2. Spanish adjectives not ending in -o are the same in the masculine and feminine:
   (masculino) El cuaderno es grande. (The notebook is big.)
   (femenino)  La casa es grande. (The house is big.)
   
   (masculino) El lápiz es azul. (The pencil is blue.)
   (femenino) La pluma es azul. (The pen is blue.)
    

Note that descriptive adjectives generally follow the noun they describe:
        una revista popular (a popular magazine)

PDF download: Spanish Lesson: Agreement of adjectives