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Ch.1 - Intro to General Chemistry
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Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
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Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: How many grams of potassium chlorate decompose to potassium chloride and 638 mL of O2 at 128°C and 752 torr?2 KClO3(s) ⟶2 KCl(s) + 3 O2(g)

Solution: How many grams of potassium chlorate decompose to potassium chloride and 638 mL of O2 at 128°C and 752 torr?2 KClO3(s) ⟶2 KCl(s) + 3 O2(g)

Problem

How many grams of potassium chlorate decompose to potassium chloride and 638 mL of O2 at 128°C and 752 torr?

2 KClO3(s) ⟶2 KCl(s) + 3 O2(g)

Solution

We’re being asked to calculate for the mass of potassium chlorate (KClO3) that decomposes into potassium chloride (KCl) and 638 mL of O2.


Decomposition reaction:             2 KClO3(s) 2 KCl(s) + 3 O2(g)


We’re going to calculate the mass of potassium chlorate using the following steps.

Step 1. Calculate the moles of O2 produced using the ideal gas equation.

PV=nRT

P = pressure, atm
V = volume, L
n = moles, mol
R = gas constant = 0.08206 (L·atm)/(mol·K)
T = temperature, K

Step 2. Calculate the moles of KClO3 decomposed using mol to mol comparison.
Step 3. Calculate the mass of KClO3 decomposed using its molar mass.

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