Avogadro's number tells you how many atoms are in 1 mol of every element.
So,
1 mol : 6.022x10^23 atoms = 0.450 moles : x atoms
There are 2.7099x10^23 atoms in 0.450 moles
The answer is B. Compound
Carbohydrates, nucleic acids and proteins
We are given a galvanic cell containing one half-cell which consists of Ag (s) and Ag+ (aq) and another half-cell that contains Cu (s) and Cu2+ (aq). The species that are produced at the electrodes under standard conditions are AgNO3 and CuNO3. <span />
<span>Cl</span>₂<span> + 2NaBr → 2NaCl + Br</span>₂
The mole ratio of Cl₂ : Br₂ is 1 : 1