the nucleus of the atom contains 8 protons and 9 neutrons. what is the mass of the nucleus?
a 8 amu
b 9 amu
c 1 amu
d 17 amu

The mass of the nucleus is 17 amu.

Explanation

Given :

Number of Protons = 8

Number of Neutrons = 9

To Find :

Mass of the nucleus = ?

Solution :

The mass of the nucleus  Mass= p+n

Where

p= protons in the atom

n= neutrons in the atom

So,  substituting the values

Mass= 8+9

Mass= 17 amu

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.