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.
Answer:
The answer is melting and freezing point.
Explanation:
Smog
formed by mixture of smoke and fog
Answer:
See explanation
Explanation:
The question is incomplete because the images of the models are absent. However, i will try to give you a general description of what the correct answer should be.
Beryllium is a member of group 2 in the periodic table. Beryllium has an atomic number of 4. This implies that it has four protons in its nucleus and four electrons in its shells. In a neutral atom, the number of electrons on the shells is equal to the number of protons in the nucleus.
The electronic configuration of Beryllium is 1s2 2s2. This implies that it should have two shells each containing only two electrons each.
Since we are using white foam balls for protons and black foam balls for neutrons, the clear plastic will contain four white foam balls and five black foam balls since the mass number of beryllium is 9 and number of neutrons = mass number - number of protons.
Four blue foam balls hanging from strings will represent the electrons around the nucleus.
Any model that corresponds to the description above is the correct answer.
