Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Answer:
Metal
Explanation:
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal chemical element. An alkali also can be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0.
Gas is the correct answer
Answer:
4d orbital.
Explanation:
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In this case, since zirconium's atomic number is 40, we fill in the electron configuration up to 40 as shown below:

Thus, the orbital 4d is partially filled.
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<h2><em>Solid. Because molecules densely packed it has a high resistance to flow thereby lower kinetic energy.
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