Chemical reactions Flashcards
(5 cards)
1
Q
What is an element?
A
A substance containing only one type of atom (e.g. Mg, O₂).
2
Q
What is a compound?
A
A substance containing two or more different types of atoms chemically bonded (e.g. H₂O).
3
Q
Why must chemical equations be balanced?
A
Due to the law of conservation of mass: atoms cannot be created or destroyed.
4
Q
What can you change when balancing equations?
A
Only the numbers in FRONT of compounds (never subscripts).
5
Q
Balancing tip?
A
Start with atoms in compounds; end with uncombined elements.
