help in chemistry thanks is urgent!
15 What is the name given to substances that are initially involved in a chemical reaction? |
16. True or false? Bases have a pH level below 7. |
17. Is sodium hydroxide (NaOH) an acid or base? |
18. Atoms of the same chemical element that have different atomic mass are known as? |
19. True or false? A proton carries a positive charge. |
20. What is the fourth most abundant element in the universe in terms of mass? |