Here are the answers to the U6L10 Chemical Change Unit Test for 7th Grade
1. chlorine (Cl)
2. They have similar reactivity.
3. burning wood
4. It is a physical change because there is no reaction.
5. They form new substances.
6. it shows that no atoms have been gained or lost during the reaction
7. The Law of Conservation of mass says that matter is neither created nor destroyed. So, we start with12.7 g + 3.2 g = 15.9 g for the reactants which means we must have 15.9 g for the products. Remember it's the products of the reaction so the scientist must know that Cu2S is the only product.
Number 7 you need to change it up a little bit