What is oxygen gas? this is research assignment that's why you need to write a molecular formula ,physical properties and collection method with diagram of oxygen. pls i need it right now

In a closed or isolated system , matter can not be created or destroyed. it can change forms but is conserved true or false

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?

A50.0 ml sample of gas at 20.0 atm of pressure is compressed to 40.0 atm of pressure at constant temperature. what is the new volume? 0.0100 ml 0.325 ml 25.0 ml 100. ml