Chemistry · Some Basic Concepts of Chemistry

Consider the following statements regarding the classification of matter: (A) Air is a homogeneous mixture. (B) Glucose contains carbon, hydrogen, and oxygen in a fixed ratio and is classified as a pure substance. (C) The components of a homogeneous mixture are visible distinctly with the unaided eye. (D) Pure substances can have variable composition depending on their preparation method. How many of the above statements are correct?

1. A
   Only one
2. B
   Only two
3. C
   Only three
4. D
   All four