객관식
What is the formula mass of calcium nitrate, Ca(NO3)2?
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3. Chemical Reactions
Stoichiometry
객관식
When heated, potassium chlorate decomposes to potassium chloride and molecular oxygen:
2 KClO3 → 2 KCl + 3 O2
How much oxygen could be formed from 5.0 g of potassium chlorate?
A
28.7 g
B
0.061 g
C
2.0 g
D
1.3 g
E
0.98 g
검증된 단계별 안내1
First, write down the balanced chemical equation for the decomposition of potassium chlorate: 2 KClO3 → 2 KCl + 3 O2.
Calculate the molar mass of potassium chlorate (KClO3) by adding the atomic masses of potassium (K), chlorine (Cl), and three oxygen (O) atoms.
Determine the number of moles of potassium chlorate in 5.0 g by dividing the mass of potassium chlorate by its molar mass.
Use the stoichiometry of the balanced equation to find the moles of oxygen gas (O2) produced. According to the equation, 2 moles of KClO3 produce 3 moles of O2.
Finally, calculate the mass of oxygen gas produced by multiplying the moles of O2 by the molar mass of O2 (32.00 g/mol).
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