How many atoms of sodium are in 3.80 mol of sodium, Na?

2.29 × 10²⁴ atoms Na

Explanation:

Step 1: Define

Avagadro's Number: 6.02 × 10²³ atoms, molecules, formula units, etc.

Step 2: Stoichiometry

= 2.2876 × 10²⁴ atoms Na

Step 3: Simplify

We have 3 sig figs.

2.2876 × 10²⁴ atoms Na ≈ 2.29 × 10²⁴ atoms Na

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