K₂SO₄ + CaI₂ → CaSO₄ + KI
K: 2 K: 1
S: 1 S: 1
O: 4 O: 4
Ca: 1 Ca: 1
I: 2 I: 1
↓
K₂SO₄ + CaI₂ → CaSO₄ + 2KI
K: 2 K: 2
S: 1 S: 1
O: 4 O: 4
Ca: 1 Ca: 1
I: 2 I: 2
Lets do process of elimination!
A. Breaking glass - That is a psychical change because if you break it, it is still glass. It didn't change to another substance.
B. Melting ice on a windshield - During the melting process, there is no chemical change, and therefore, no new substance is created.
C. Burning gasoline - When gas burns it usually combines with oxygen to give carbon dioxide, water etc. It is a chemical change.
D. Denting a bumper - The bumper is still a bumper, only thing is it has a dent in it. The properties did not change, meaning no chemical change.
8. A - they’re repeating the action
9. B -Frank, himself hasn’t done the experiment before
49.1-45.5=3.6; you simply subtract the old density from the new density.
1. They use the same measuring system (metric)
2. Clearly and properly collect and record data, recording the procedure and results
3. Releasing the data into the public, letting everyone have access to it
maybe, I don't know what answer your teacher wants