Given :
Number of atoms of an element, n = 2.072 × 10⁴³ atoms.
To Find :
Number of moles of that element in given number of atoms.
Solution :
We know, 1 mole of any element contains 6.022 × 10²³ atoms.
So, number of moles in given number of atoms are :

Hence, this is the required solution.
The molecule of that compound! Hope this helps!
Answer:
Demonstration 1 showed a chemical change because a new gaseous substance was formed, and demonstration 2 showed a physical change because liquid water became water vapor.
Explanation:
Chemical changes alter the chemical makeup of a subject, and a physical change only alters the appearance of a subject, not the chemical makeup.
Answer:
1:is option A as it have OH- group (base)
2:a),antacid as it's weak base