Answer:
2.237 x 10²⁴ molecules CH₃CO₂K
Step-by-step explanation:
To find the amount of molecules, you need to (1) convert grams to moles (using the molar mass of potassium acetate) and then (2) convert moles to molecules (using Avogadro's Number). It is important to arrange the ratios in a way that allows for the cancellation of units. The final answer should have 4 sig figs like the given value (3.645 x 10² = 4 sig figs).
Atomic Mass (C): 12.011 g/mol
Atomic Mass (H): 1.008 g/mol
Atomic Mass (O): 15.999 g/mol
Atomic Mass (K): 39.098 g/mol
Molar Mass (CH₃CO₂K):
2(12.011 g/mol) + 3(1.008 g/mol) + 2(15.999 g/mol) + 39.098 g/mol
= 98.142 g/mol
Avogadro's Number:
6.022 x 10²³ molecules = 1 mole
3.645 x 10² g CH₃CO₂K 1 mole 6.022 x 10²³ molecules
------------------------------------- x ----------------- x ------------------------------------- =
98.142 g 1 mole
= 2.237 x 10²⁴ molecules CH₃CO₂K