Which of the substances in the chemical equation is a pure substance?
A. Carbon
B. Carbon Dioxide
C. Oxygen
D. All Of These

Of the groups of elements below, which are most likely to gain electrons to become anions? a. alkali metal b. boron group c. halogen d. transition metal

What is avogadro’s number, and why is it useful

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line