I think the answer would be
A. They find the number of protons
An atom of any element must contain...
an equal number of protons and electrons
Answer:
12.6 g O2 or
12.60 g O2 (if needed two decimal places)
Explanation:
First convert grams into moles:
17.4 g KCl × <u> </u><u> </u><u> </u><u> </u><u> </u><u>1</u><u> </u><u> </u><u> </u><u> </u><u> </u>
74.55
= 0.233 moles of KCl
Next solve for the mole of O2:
= 0.233 × <u>3</u><u> </u><u>m</u><u>o</u><u>l</u><u>e</u><u>s</u><u> </u><u>o</u><u>f</u><u> </u><u>O</u><u>2</u>
2 moles of KCl
= 0.3495 or
= 0.350 moles of O2
Finally convert the mole to grams:
= 0.350 moles of O2 × <u> </u><u> </u><u> </u><u>36</u><u>g</u><u> </u><u> </u>
1 mole
= 12.6 g O2 or 12.60 g O2