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What is the main purpose of a bomb calorimeter?
What is the main purpose of a bomb calorimeter?
What material is the cylindrical bomb in a bomb calorimeter primarily made of?
What material is the cylindrical bomb in a bomb calorimeter primarily made of?
How is the initial temperature of water in a bomb calorimeter represented?
How is the initial temperature of water in a bomb calorimeter represented?
What must be done to maintain a uniform temperature during the calorimetric experiment?
What must be done to maintain a uniform temperature during the calorimetric experiment?
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Which of the following components is NOT considered in Dulong’s formula for calorific value?
Which of the following components is NOT considered in Dulong’s formula for calorific value?
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What does proximate analysis of coal determine?
What does proximate analysis of coal determine?
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In a bomb calorimeter, what happens to the oxygen supplied for combustion?
In a bomb calorimeter, what happens to the oxygen supplied for combustion?
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What is the significance of measuring the final temperature in the calorimeter experiment?
What is the significance of measuring the final temperature in the calorimeter experiment?
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What is the primary cause of temporary hardness in water?
What is the primary cause of temporary hardness in water?
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Which method can be used to remove permanent hardness from water?
Which method can be used to remove permanent hardness from water?
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How is the degree of hardness in water typically expressed?
How is the degree of hardness in water typically expressed?
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Which unit is equivalent to 1 ppm in terms of hardness measurement?
Which unit is equivalent to 1 ppm in terms of hardness measurement?
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What happens when hard water reacts with soap?
What happens when hard water reacts with soap?
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What is a common result of the dissolved solids in water when it is converted to steam in a boiler?
What is a common result of the dissolved solids in water when it is converted to steam in a boiler?
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What type of water hardness is NOT removed by simply boiling water?
What type of water hardness is NOT removed by simply boiling water?
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Which of the following is a method NOT used for removing permanent hardness?
Which of the following is a method NOT used for removing permanent hardness?
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What is the primary cause of scale formation in boilers?
What is the primary cause of scale formation in boilers?
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Which of the following is a consequence of scale and sludge formation in a boiler?
Which of the following is a consequence of scale and sludge formation in a boiler?
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What chemical is used in Calgon treatment to convert CaSO4 into a soluble complex?
What chemical is used in Calgon treatment to convert CaSO4 into a soluble complex?
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What is the purpose of the blow down operation in a boiler?
What is the purpose of the blow down operation in a boiler?
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Which process is referred to as the permutit process?
Which process is referred to as the permutit process?
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What type of compounds do sodium phosphates form when added to boiler water?
What type of compounds do sodium phosphates form when added to boiler water?
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What is the chemical formula of zeolite?
What is the chemical formula of zeolite?
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What happens to scales as a result of uneven expansion?
What happens to scales as a result of uneven expansion?
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What happens to zeolite when it becomes exhausted?
What happens to zeolite when it becomes exhausted?
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What is the role of the cation exchange resin in the ion-exchange process?
What is the role of the cation exchange resin in the ion-exchange process?
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How can exhausted ion-exchange columns be regenerated?
How can exhausted ion-exchange columns be regenerated?
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What is the primary purpose of using hydrated lime in the lime-soda process?
What is the primary purpose of using hydrated lime in the lime-soda process?
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Which type of impurities does sodium carbonate primarily target in the lime-soda process?
Which type of impurities does sodium carbonate primarily target in the lime-soda process?
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What is osmotic pressure in the context of reverse osmosis?
What is osmotic pressure in the context of reverse osmosis?
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Which ion is primarily formed from the cation exchange resin during the ion-exchange process?
Which ion is primarily formed from the cation exchange resin during the ion-exchange process?
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What results from the reaction of MgSO4 with hydrated lime in water treatment?
What results from the reaction of MgSO4 with hydrated lime in water treatment?
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What does the loss in weight after heating a moisture-free coal sample in a muffle furnace at 950°C indicate?
What does the loss in weight after heating a moisture-free coal sample in a muffle furnace at 950°C indicate?
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How is ash content in coal determined?
How is ash content in coal determined?
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What is the significance of low moisture content in coal?
What is the significance of low moisture content in coal?
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Which substances are measured during the ultimate analysis of coal?
Which substances are measured during the ultimate analysis of coal?
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What happens to nitrogen during the Kjeldahl analysis of coal?
What happens to nitrogen during the Kjeldahl analysis of coal?
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What does fixed carbon content reflect in coal quality analysis?
What does fixed carbon content reflect in coal quality analysis?
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What indicates the weight loss in the initial step involving moisture removal?
What indicates the weight loss in the initial step involving moisture removal?
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Why is low ash content preferable in coal?
Why is low ash content preferable in coal?
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Study Notes
Hardness of Water
- Hard water does not produce lather with soap due to dissolved minerals.
- Hardness is mainly caused by calcium (Ca) and magnesium (Mg) salts.
- Hard water reacts with soap to form insoluble precipitates (calcium and magnesium stearate).
Types of Hardness
-
Temporary Hardness:
- Caused by bicarbonates of Ca and Mg.
- Removable by boiling, which converts bicarbonates into insoluble carbonates.
- Can also be treated with hydrated lime to precipitate insoluble carbonate.
-
Permanent Hardness:
- Results from soluble salts of Ca and Mg such as chlorides and sulfates.
- Cannot be eliminated by boiling or lime; requires methods like the lime-soda process or ion-exchange.
Degree of Hardness
- Expressed in terms of calcium carbonate (CaCO3) equivalent.
- Units include:
- Parts per million (ppm)
- Milligrams per liter (mg/L)
- Degree Clarke (°Cl)
- Degree French (°Fr)
- Relationships: 1 ppm = 1 mg/L = 0.07 °Cl = 0.1 °Fr.
Boiler Troubles
- Boilers produce steam but accumulate dissolved and suspended solids, leading to scale and sludge formation.
- Scales: Hard deposits from compounds like CaCO3 and Mg(OH)2, mainly in the hot areas of the boiler.
- Sludge: Soft, loose precipitates formed in colder areas from compounds like CaCl2 and MgSO4.
- Issues caused by scales and sludge include:
- Inefficient heat transfer, leading to increased fuel consumption.
- Risk of boiler explosions due to sudden pressure buildup.
Boiler Trouble Removal Techniques
-
Internal Treatment:
- Blow down operation to remove sludge through a bottom outlet.
- Chemical treatments for scales:
- Calgon Treatment: Uses sodium meta hexaphosphate to convert CaSO4 into soluble complexes.
- Phosphate Treatment: Na3PO4 forms soft sludge from hardness minerals, removable by blow-down.
-
External Treatment Methods:
- Zeolite Process: Ion exchange using hydrated sodium aluminum silicate, which replaces hardness ions with Na+.
- Ion-Exchange Resin: Two-column system removes cations and anions; regenerated using dilute acids and bases.
- Lime-Soda Process: Hydrated lime removes temporary hardness; soda ash addresses permanent hardness due to Ca and Mg salts.
- Reverse Osmosis: Uses osmotic pressure to filter out impurities through a semi-permeable membrane.
Calorific Value Determination
- Bomb Calorimeter: Utilizes a stainless steel bomb for combusting fuel in an oxygen-rich environment to measure energy released.
- Calculation Process: Determines calorific value based on the increase in temperature of water during combustion, using specific formulae for mass and temperature measurements.
- Theoretical Calculation: Dulong’s formula estimates calorific value based on the percentages of carbon, hydrogen, oxygen, and sulfur in the fuel.
Coal Analysis
-
Proximate Analysis measures:
- Moisture Content: Loss measured after drying coal sample in an oven.
- Volatile Matter: Amount lost during heating in a muffle furnace.
- Ash: Residue after combustion, representing non-combustible materials.
- Fixed Carbon: Calculated as the difference between total weight and the sum of moisture, volatile matter, and ash.
-
Ultimate Analysis: Determines carbon, hydrogen, nitrogen, sulfur, and oxygen content.
- Uses combustion apparatus to analyze CO2 and H2O generation from combustion of coal.
- Nitrogen measurement involves conversion to ammonium sulfate and subsequent distillation to quantify ammonia absorbed in acid.
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Description
Test your knowledge on the hardness of water, focusing on its types, degrees, and the impact of dissolved minerals. Understand the differences between temporary and permanent hardness, and explore the methods used to treat hard water. This quiz will help solidify your understanding of an essential topic in water chemistry.
