6. Calculate the number of grams of potassium chloride, KCl, that will be formed by the decomposition of 6.45 grams of potassium chlorate, KClO3. Oxygen gas, O2, is the other product.
So far I have gotten
2 KClO3 2 KCl + 3 O2
2.53 grams of KCL
BUT I NEED THE MASS OF KCL!
Chemistry KCLO3 Question?
2016-06-21 6:09 pm
回答 (2)
2016-06-21 6:21 pm
6.
Molar mass of KClO₃ = (39.01 + 35.45 + 16.00×3) g/mol = 122.46 g/mol
Molar mass of KCl = (39.01 + 35.45) g/mol = 74.46 g/mol
2KClO₃ → 2KCl + 3O₂
OR: Mole ratio KClO₃ : KCl = 2 : 2 = 1 : 1
No. of moles of KClO₃ decomposed = (2.53 g) / (122.46 g/mol) = 2.53/122.46 mol
No. of moles of KCl formed = 2.53/122.46 mol
Mass of KCl formed = (74.46 g/mol) × (2.53/122.46 mol) = 1.54 g
Molar mass of KClO₃ = (39.01 + 35.45 + 16.00×3) g/mol = 122.46 g/mol
Molar mass of KCl = (39.01 + 35.45) g/mol = 74.46 g/mol
2KClO₃ → 2KCl + 3O₂
OR: Mole ratio KClO₃ : KCl = 2 : 2 = 1 : 1
No. of moles of KClO₃ decomposed = (2.53 g) / (122.46 g/mol) = 2.53/122.46 mol
No. of moles of KCl formed = 2.53/122.46 mol
Mass of KCl formed = (74.46 g/mol) × (2.53/122.46 mol) = 1.54 g
2016-06-21 7:39 pm
Write the fully BALANCED reaction equation.
2KClO3 ==heat==> 2KCl + O2
Note the molar ratios are 2 : : 2 ; 1
Next remember the equation
moles = mass(g) / Mr
The 'Mr' of KClO3 is
K x 1 = 39 x 1 = 39
Cl x 1 = 35.5 x 1 = 35.5
O x 3 = 16 x 3 = 48
39 + 35.5 + 48 = 122.5
Hence mol(KClO3) = 6.45 g / 122.5 = 0.05265 moles (Equivalent to '2' in the molar ratios above).
mol(KCl) = 0.05265 moles ( Also equivalent to '2' in the molar ratios above).
mass(KCl) = moles x Mr(KCl) = 0.05265 x ( 39 + 35.5) =>
mass(KCl) = 0..05265 x 74.5 = 3.92 g
Done !!!
Hope that helps!!!!
2KClO3 ==heat==> 2KCl + O2
Note the molar ratios are 2 : : 2 ; 1
Next remember the equation
moles = mass(g) / Mr
The 'Mr' of KClO3 is
K x 1 = 39 x 1 = 39
Cl x 1 = 35.5 x 1 = 35.5
O x 3 = 16 x 3 = 48
39 + 35.5 + 48 = 122.5
Hence mol(KClO3) = 6.45 g / 122.5 = 0.05265 moles (Equivalent to '2' in the molar ratios above).
mol(KCl) = 0.05265 moles ( Also equivalent to '2' in the molar ratios above).
mass(KCl) = moles x Mr(KCl) = 0.05265 x ( 39 + 35.5) =>
mass(KCl) = 0..05265 x 74.5 = 3.92 g
Done !!!
Hope that helps!!!!
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