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Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ?
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Igniting MnO2 in air converts it quantitatively to Mn204 A sample of p...
Ans.
3 MnO2 → Mn3O4
3 (54.9 + 32) (3 * 54.9 + 64)
= 260.7 g = 228.7 g
Let the amount of pyrolusite ignited = 100.00 g
∴ Wt. of MnO2 = 80 g (80% of 100 g = 80 g)
Wt. of SiO2� and other inert substances = 15 g
Wt. of water 100 – (80 + 15) = 5 g
According to equation,
260.7 g of MnO2 gives = 228.7 g of Mn3O4
∴ 80 g of MnO2 gives = 228.7/260.7 * 80 = 70.2 g of Mn3O4
NOTE :
During ignition, H2O present in pyrolusite is removed while silica and other inert substances remain as such.
∴ Total wt. of the residue = 70.2 + 15 = 85.2 g
Calculation of % of Mn in ignited Mn3O4
3 Mn = Mn3O4
3 * 54.9 = 164.7 g 3 * 54.9 + 64 = 228.7g
Since, 228.7 g of Mn3O4 contains 164.7 g of Mn
70.2 g of Mn3O4 contains = 164.7/228.7 * 70.2 = 50.55 g of Mn
Weight of resdue = 85.2 g
Hence, percentage of Mn is the ignited sample
= 50.55/85.2 * 100 =
59.33%
This question is part of UPSC exam. View all JEE coursesMost Upvoted Answer
Igniting MnO2 in air converts it quantitatively to Mn204 A sample of p...
Introduction:
In this problem, we are given a sample of pyrolusite which contains manganese dioxide (MnO2), silicon dioxide (SiO2), and water. We need to determine the percentage of manganese (Mn) in the ignited sample after heating it in air to constant mass.
Given:
- Percentage of MnO2 in the sample: 80%
- Percentage of SiO2 in the sample: 15%
- Rest of the sample contains water
Explanation:
When MnO2 is ignited in air, it undergoes a chemical reaction and converts quantitatively to MnO4. This means that the mass of MnO2 remains the same after ignition.
To find the percentage of Mn in the ignited sample, we need to calculate the mass of MnO2 and divide it by the total mass of the ignited sample.
Step 1: Calculate the mass of MnO2:
Since the percentage of MnO2 in the sample is given as 80%, we can assume that 100g of the sample contains 80g of MnO2.
Step 2: Calculate the total mass of the sample:
To find the total mass of the sample, we need to consider the mass percentages of MnO2, SiO2, and water.
- Mass of MnO2 = 80g
- Mass of SiO2 = 15g (given as 15% of the sample)
- Mass of water = Total mass - (Mass of MnO2 + Mass of SiO2)
Assuming the total mass of the sample is 100g, we can calculate the mass of water as follows:
Mass of water = 100g - (80g + 15g) = 5g
Therefore, the total mass of the sample is 100g.
Step 3: Calculate the percentage of Mn in the ignited sample:
As mentioned earlier, the mass of MnO2 remains the same after ignition. So, the mass of MnO2 in the ignited sample is still 80g.
To find the percentage of Mn in the ignited sample, we divide the mass of MnO2 by the total mass of the ignited sample and multiply by 100.
Percentage of Mn in the ignited sample = (Mass of MnO2 / Total mass of ignited sample) * 100
= (80g / 100g) * 100
= 80%
Conclusion:
The percentage of Mn in the ignited sample is 80%. By following the given steps, we calculated the mass of MnO2 in the original sample and divided it by the total mass of the ignited sample to find the percentage of Mn.
In this problem, we are given a sample of pyrolusite which contains manganese dioxide (MnO2), silicon dioxide (SiO2), and water. We need to determine the percentage of manganese (Mn) in the ignited sample after heating it in air to constant mass.
Given:
- Percentage of MnO2 in the sample: 80%
- Percentage of SiO2 in the sample: 15%
- Rest of the sample contains water
Explanation:
When MnO2 is ignited in air, it undergoes a chemical reaction and converts quantitatively to MnO4. This means that the mass of MnO2 remains the same after ignition.
To find the percentage of Mn in the ignited sample, we need to calculate the mass of MnO2 and divide it by the total mass of the ignited sample.
Step 1: Calculate the mass of MnO2:
Since the percentage of MnO2 in the sample is given as 80%, we can assume that 100g of the sample contains 80g of MnO2.
Step 2: Calculate the total mass of the sample:
To find the total mass of the sample, we need to consider the mass percentages of MnO2, SiO2, and water.
- Mass of MnO2 = 80g
- Mass of SiO2 = 15g (given as 15% of the sample)
- Mass of water = Total mass - (Mass of MnO2 + Mass of SiO2)
Assuming the total mass of the sample is 100g, we can calculate the mass of water as follows:
Mass of water = 100g - (80g + 15g) = 5g
Therefore, the total mass of the sample is 100g.
Step 3: Calculate the percentage of Mn in the ignited sample:
As mentioned earlier, the mass of MnO2 remains the same after ignition. So, the mass of MnO2 in the ignited sample is still 80g.
To find the percentage of Mn in the ignited sample, we divide the mass of MnO2 by the total mass of the ignited sample and multiply by 100.
Percentage of Mn in the ignited sample = (Mass of MnO2 / Total mass of ignited sample) * 100
= (80g / 100g) * 100
= 80%
Conclusion:
The percentage of Mn in the ignited sample is 80%. By following the given steps, we calculated the mass of MnO2 in the original sample and divided it by the total mass of the ignited sample to find the percentage of Mn.
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Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ? for JEE 2026 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ? covers all topics & solutions for JEE 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ?.
Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ? for JEE 2026 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ? covers all topics & solutions for JEE 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Igniting MnO2 in air converts it quantitatively to Mn204 A sample of pyrolusite has Mno, 80%, SiO2 15% and rest having water. The sample is heated in air to constant mass. What is the % of Mn in ignited sample ? ?.
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