An atom with 7 protons, 6 neutrons, and 7 electrons has an atomic mass of amu. (enter a whole number.)

Answer : An atom with 7 protons, 6 neutrons, and 7 electrons has an atomic mass of 13 amu.

Explanation :

As we are give that,

Number of protons = 7

Number of electrons = 7

Number of neutrons = 6

As we know that,

Atomic number =Number of protons = Number of electrons = 7

Atomic mass = Number of neutrons + Atomic number

Atomic mass = 6 + 7 = 13 amu

Therefore, the atomic mass is, 13 amu

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

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e