The number of atoms in 0.004g of magnesium is close to

Correct answer: C. 1020

  • A. 24
  • B. 2 x 10^20
  • C. 1020
  • D. 6.02 x 10^23

Explanation

Here's how to calculate the number of atoms in 0.004g of magnesium:Calculate the number of moles of magnesium:Mass of magnesium (m) = 0.004 gMolar mass of magnesium (M) = 24.305 g/mol (rounded to four decimal places for accuracy)Number of moles (n) = mass / molar massn = 0.004 g / 24.305 g/mol ≈ 0.000165 molUse Avogadro's constant to find the number of atoms:Avogadro's constant (N_A) = 6.022 x 10^23 atoms/mol (represents the number of atoms in one mole of a substance)Number of atoms = number of moles * Avogadro's constantNumber of atoms ≈ 0.000165 mol * 6.022 x 10^23 atoms/mol ≈ 1 x 10^20 atomsTherefore, the number of atoms in 0.004g of magnesium is close to 1 x 10^20.

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Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.

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