Answer:
(a) Na₂Cr₂O₇ , 262 g/mol
(b) NH₄ClO₄, 117.5 g/mol
(c) Mg(NO₂)₂.3H₂O, 170.3 g/mol
Explanation:
<u>(a) Sodium dichromate </u>
The formula for the compound is: <u>Na₂Cr₂O₇</u>
Calculation of the molecular mass as:
Molar mass of sodium = 23 g/mol
Molar mass of chromium = 52 g/mol
Molar mass of oxygen = 16 g/mol
<u>So, Molecular mass of sodium dichromate = (23×2) + (52×2) + (16×7) = 262 g/mol</u>
<u>(b) ammonium Perchlorate</u>
The formula for the compound is: <u>NH₄ClO₄</u>
Calculation of the molecular mass as:
Molar mass of nitrogen = 14 g/mol
Molar mass of hydrogen = 1 g/mol
Molar mass of chlorine = 35.5 g/mol
Molar mass of oxygen = 16 g/mol
<u>So, Molecular mass of ammonium Perchlorate = (14×1) + (1×4) + (35.5×1) + (16×4)= 117.5 g/mol</u>
<u>(c) magnesium nitrite trihydrate</u>
The formula for the compound is: <u>Mg(NO₂)₂.3H₂O</u>
Calculation of the molecular mass as:
Molar mass of Magnesium = 24.3 g/mol
Molar mass of nitrogen = 14 g/mol
Molar mass of hydrogen = 1 g/mol
Molar mass of oxygen = 16 g/mol
<u>So, Molecular mass of magnesium nitrite trihydrate = (24.3×1) + (14×2) + (16×7) + (1×6)= 170.3 g/mol</u>