Mass and energy are conserved Question 11 options: A) only in chemical changes. B) always in physical changes and sometimes in chemical changes. C) only in physical changes. D) in chemical changes and physical changes.

Which statement about the stamps is correct?

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?

How have the greenhouse gasses increased from the year 2000 to 2018