Question

How many grams of oxygen are in 2.46×1023 formula units of (NH4)2SO4?
Express your answer to three significant figures and include the appropriate units.

Answer 1

Answer on Question #55412 – Chemistry – General chemistry

Question:

How many grams of oxygen are in $2.46 \times 10^{23}$ formula units of $(\mathrm{NH}_4)_2\mathrm{SO}_4$?

Express your answer to three significant figures and include the appropriate units.

Solution:

$$v_{(\mathrm{NH}_4)_2\mathrm{SO}_4} = N_{(\mathrm{NH}_4)_2\mathrm{SO}_4} / N_A$$ $$v_O = 4 v_{(\mathrm{NH}_4)_2\mathrm{SO}_4}$$ $$m_O = v_O \times M_O = 4 M_O \times N_{(\mathrm{NH}_4)_2\mathrm{SO}_4} / N_A = 4 \times 15.999 \, \mathrm{g} \, \mathrm{mol}^{-1} \times 2.46 \times 10^{23} / 6.02 \times 10^{23} \, \mathrm{mol}^{-1} = 26.2 \, \mathrm{g}$$

Answer: 26.2 g

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