The cost of one antacid is 2.325 cents per tablet.
<u>Explanation:</u>
As per the question based on the student analysis we know that,
Total antacid tablets in a bottle = 120
Purchase Price of a bottle = $ 2.79
Cost of 1 antacid tablet 
As we know $1 = 100 cent
The cost of 1 antacid tablet = 
× 100 cents = 2.325 cents/tablet
.
Thus we came to know that it costs 2.325 cents/tablet
.
Cu⇒ 1 atom
N⇒2 atoms
O⇒6 atoms
Total 9 atoms
<h3>Further explanation </h3>
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
<em>(empirical formula) n = molecular formula </em>
Chemical formula : Cu(NO₃)₂
Number of Cu : 1
Number of N : 2
Number of O = 2 x 3 = 6
Total atoms in Cu(NO₃)₂ : 1 + 2 + 6 = 9
85-12 = 73 degrees needed
4.186 J/degree Celsius, so
73 degrees * 4.186 J/degree = 305.578 J to raise 1 gram 73 degrees
there are 675 grams, so 305.578 * 675 = 206265.15 J
2.06 x 10^5 J are needed
<h2>
Answer:</h2>
Option B. Potassium(K).
<h2>
Explanation:</h2>
Electronic configuration of the given elements are:
- Ca - [Ar] 4s²
- K - [Ar] 4s¹
- B - [He] 2s2 2p1
- Kr - [Ar] 3d¹⁰4s²4p⁶
- Krypton(K) have 36 electrons and it is a noble gas and hence all of its shells are completely filled with electrons and hence it will never loose electrons in normal conditions.
- Boron(B) have 5 electrons and 3 electrons in its outer shell. In order to attain a stable configuration it will loose 3 electrons and it is difficult to loose 3 electrons at a time for an atom.
- Calcium(Ca) have 20 electrons and 2 electrons in its outermost shell, in order to attain a stable configuration it will loose 2 electrons. it is quite difficult but easier than Boron.
- Potassium(K) have 21 electrons and 1 electron in its outermost orbit and in order to attain a stable configuration it will loose 1 electron. It is much easier to donate 1 electron than 2 or 3 electrons.
Result: Potassium will loose an electron most easily from the given elements.
