Matter is classified as a
(1) substance, only
(2) substance or as a mixture of substances
(3) homogenous mixture, only
(4) homogenous mixture or as a heterogeneous mixture

Why should the scientific method be used to answer a question? a. it provides a way to test an idea without any bias. b. it provides a way to test a hypothesis. c. it provides a way to ensure all hypotheses are proven correct. d. it provides a way to quickly turn a hypothesis into a scientific theory.

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?