A. The number of molecules in 0.750 mole of KNO₃ is 4.515×10²³ molecules
B. The mass (in milligrams) of 2.39×10²⁰ molecules of Ag₂SO₄ is 124 mg
C. The number of molecules in 3.429 g of NaHCO₂ is 3.04×10²² molecules
<h3>Avogadro's hypothesis </h3>
1 mole of substance = 6.02×10²³ molecules
<h3>A. How to determine the number of molecules </h3>
1 mole of KNO₃ = 6.02×10²³ molecules
Therefore,
0.750 mole of KNO₃ = 0.75 × 6.02×10²³
0.750 mole of KNO₃ = 4.515×10²³ molecules
<h3>B. How to determine the mass of Ag₂SO₄</h3>
6.02×10²³ molecules = 312 g of Ag₂SO₄
Therefore,
2.39×10²⁰ molecules = (2.39×10²⁰ × 312) / 6.02×10²³
2.39×10²⁰ molecules = 0.124 g
Multiply by 1000 to express in mg
2.39×10²⁰ molecules = 0.124 g × 1000
2.39×10²⁰ molecules = 124 mg of Ag₂SO₄
<h3>C. How to determine the number of molecules </h3>
68 g of NaHCO₂ = 6.02×10²³ molecules
Therefore,
3.429 g of NaHCO₂ = (3.429 × 6.02×10²³) / 68
3.429 g of NaHCO₂ = 3.04×10²² molecules
Learn more about Avogadro's number:
brainly.com/question/26141731
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