Answer:
protons
Explanation:
the number of protons in 1 atom determine the identity
Answer: most store-bought isnt
Explanation:
there typically a lot of addivitves
Answer:
D. Separating a salt solution by evaporating the water
Explanation:
B. Allowing a nail to rust is a chemical change.
Becuase once the nail rust it turns into flakes and therefore is no longer a nail.
C. building a model rocket propelled by mixing baking soda and vinegar
By mixing baking soda (a powder) into vinegar ( a Acid) it causes a explosion...
the baking soda dissolve into the acid.... This a chemical reaction
A.creating salt by reacting sodium metal and chlorine gas
Sodium is salt but it says.... Sodium metal..... chlorine gas Changes color and it has a strong odor... chlorine gas with sodium metal turns it into salt.... it doesnt stay a metal or a gas it CHANGES.....
so therefore its a Chemical change
When A object or substance changes form or it causes a exsplosion or reaction it is a chemical change.
D. Separating a salt solution by evaporating the water
For a physical change your object may change color or shape but its still the same object.
salt in water ... The salt dont dissolve it just salty water.
So seperating salt by evaporating the water is a physical change.
Answer:
c and d, are you supposed to check 3? or only 2?
Answer: When a substance is pure, it is composed of one type of molecule. For example, table salt is only composed of (more or less) salt molecules, while seawater has water and salt molecules. A more complicated example of a non - pure substance is soil. It has many different types of nutrients and compounds.
