1 When elements form compounds, the elements

always change their physical state

react to form a new substance with new properties

keep their original properties.

combine in a random fashion

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change

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