Description : Write chemical equation reactions taking place when carried out with the help of (a) Iron reacts with steam (b) Magnesium reacts with dil HCl (c) Copper is heated in air. -Chemistry
Last Answer : This is the Answer.
Description : A piece of magnesium ribbon was heated to redness in an atmosphere of nitrogen and then cooled with water. The gas evolved is
Last Answer : A piece of magnesium ribbon was heated to redness in an atmosphere of nitrogen and then cooled with ... . ammonia B. hydrogen C. nitrogen D. oxygen
Description : Which one of the following gases is liberated when ethyl alcohol is heated with methyl magnesium iodide?
Last Answer : Which one of the following gases is liberated when ethyl alcohol is heated with methyl magnesium ... Methane B. Ethane C. Carbondioxide D. Propane
Description : Would air trapped between layers of glass cause the glass to break when heated to high temperatures?
Last Answer : answer:When heating, you're essentially increasing the pressure exerted by the air on the glass in which it's trapped. As the air has no means of escape if enough heat is added the increased pressure ... just putting in a single sheet and seeing if you get the same results without the air pressure.
Description : Give reasons for the following observations: (a) The element carbon forms a very large number of compounds. (b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame. (c) Use of synthetic detergents causes pollution of water. -Chemistry
Last Answer : Answer. (a) Carbon forms large number of compounds since carbon is small in size and can form stable covalent bonds (catenation) and it shows tetravalency. (b) Air holes of gas burner are ... not get blackened. (c) Some synthetic detergents are non-biodegradable, therefore, cause pollution of water.
Description : Write balanced equations for the reaction of: (i) aluminium when heated in air. Write the name of the product. (ii) iron with steam. Name the product obtained. (iii) calcium with water. Why does calcium start floating in water? -Chemistry
Last Answer : The bubbles of hydrogen stick to the surface of metal that is why it floats.
Description : What kind of combustion is observed in alkanes? Why do air holes of a gas burner have to be adjusted when vessel being heated gets blackened by the flame? -Science
Last Answer : Alkanes are saturated hydrocarbons and generally burn in air with a blue, non-sooty flame. If the bottoms of the cooking vessels in our homes are getting blackened, it shows that the air holes of the gas stove are getting blocked and the fuel is not burning completely.
Description : When ore is heated generally in absence of air then what is process called? -Do You Know?
Last Answer : answer:
Description : What is formed when white phosphorus is heated at 540 K in the absence of air? -Do You Know?
Description : `Ag_(2)S` ore Is mixed with NaCl and heated in the presence of air then products formed are
Last Answer : `Ag_(2)S` ore Is mixed with NaCl and heated in the presence of air then products formed are A. `AgCl+Na_(2)SO_( ... S` C. `AgCl+SO_(2)` D. `Ag+SO_(2)`
Description : Iron sulphide is heated in air to form A, an oxide of sulphur. A is dissolved in water to give an acid. The basicity of this acid is..
Last Answer : Iron sulphide is heated in air to form A, an oxide of sulphur. A is dissolved in water to give an acid. The ... acid is.. A. 2 B. 3 C. 1 D. Zero
Description : What happens when sulphur is heated in absence of air?
Last Answer : Sulfur is melted.
Description : What happen with the air in a soccer ball with a cooled and heated?
Last Answer : The air pressure goes down when cooled, goes up when heated. Asoccer ball left outdoors in freezing weather does not have muchbounce. Left outside on a hot day, has a lot of bounce.
Description : Air at dry bulb temperature Td1 is passed through the heating coil and some amount of air is by passed unaffected and leaves with dry bulb temperature Tb2 and the temperature of heated air is Td3 (where Td2 < Td3), what is the ... - Td1) / (Td2 - Td3) D. Bypass Factor = (Td2 - Td3) / (Td2 - Td1)
Last Answer : ANSWER : D
Description : What is the perfect condition for dehumidification of air? A. air is heated above its dew point temperature B. air is cooled up to its dew point temperature C. air is heated below its dew point temperature D. air is cooled below its dew point temperature
Description : When the humidity ratio of air increases the air is said to be A. dehumidified B. humidified C. heated D. cooled
Last Answer : ANSWER : B
Description : The power required to drive a turbo compressor for a given pressure ratio decreases when A. Air is heated at entry B. Air is cooled at entry C. Air is cooled at exit D. Air is heated at exit
Description : When ore is heated generally in absence of air then what is process called?
Last Answer : Calcination
Description : What is formed when white phosphorus is heated at 540 K in the absence of air?
Last Answer : Red phosphorus
Description : Which substance is obtained when coal is heated in the absence of air?
Last Answer : Coke
Description : Absolute vapor pressure of petrofuels is found by Reid bomb which is heated in water bath to 100°F. In Reid apparatus, the ratio of the volume of air chamber to that of the liquid fuel chamber is (A) 4 (B) 3 (C) 2 (D) 1
Last Answer : (A) 4
Description : Air at a particular humidity is heated in a furnace. The new dew point (A) Decreases (B) Increases (C) Depends on the extent of heating (D) Remain unchanged
Last Answer : (B) Increases
Description : Why is that on being heated in excess supply of air K,Rb and Cs forms superoxide’s instead of Oxides & peroxides?
Last Answer : Ans.K + ,Rb+ and Cs+ are large cations and superoxide ion is larger than oxide and peroxide ions. Since due to higher lattice energies,a large cation stabilizes a large anion,therefore these metals form Superoxides.
Description : When an unsaturated air-water mixture is heated at constant pressure, then (A) The partial pressure of water vapour increases (B) The specific humidity decreases (C) The relative humidity increases (D) The relative humidity decreases
Last Answer : D) The relative humidity decreases
Description : A cube, sphere & a thin circular plate (all having same mass and made of same material) are all heated to 300°C and allowed to cool in natural air. Which one will cool the slowest? (A) Cube (B) Plate (C) Sphere (D) All will cool at the same rate
Last Answer : (D) All will cool at the same rate
Description : Air is best heated with steam in a heat exchanger of (A) Plate type (B) Double pipe type with fin on steam side (C) Double pipe type with fin on air side (D) Shell and tube type
Last Answer : (C) Double pipe type with fin on air side
Description : Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both ... steam on shell side (D) Shell and tube heat exchanger with air on shell side and steam inside tubes
Last Answer : (B) Finned tube heat exchanger with air outside and steam inside
Description : Pick out the wrong statement. (A) In process heat exchangers, saturated steam is preferred over the superheated steam (B) The maximum is the emissive power of a surface at a temperature T1 ... under natural convection conditions, the velocity profile in air, normal to the plate, exhibits a maximum
Last Answer : (B) The maximum is the emissive power of a surface at a temperature T1 occurs at a wavelength of λ1 . If the surface temperature is halved, the maximum in the emissive power would occur at a wavelength of 0.5 λ1
Description : Coal is heated in presence of air to a temperature of about __________ °C, while determining its ash content for proximate analysis. (A) 500 (B) 750 (C) 950 (D) 1100
Last Answer : (B) 750
Description : When the coal is heated in absence of air, it is called its (A) Deoxidation (B) Gasification (C) Coalification (D) Carbonisation
Last Answer : (D) Carbonisation
Description : Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximateanalysis. (A) 550 (B) 750 (C) 950 (D) 1150
Last Answer : (C) 950
Description : Both white phosphorous as well as red phosphorous (A) Are soluble in CS2 (B) Burns when heated in air (C) Reacts with hot caustic soda solution to give Phosphine (D) All (A), (B), and (C)
Last Answer : (B) Burns when heated in air
Description : In tropical regions, (A) The surface gets heated more effectively than the arctic areas (B) After heating, the air becomes lighter and is displaced by cool air from the polar regions (C) The rising tropical air flows towards the polar region in the upper strata (D) All of the above
Last Answer : (D) All of the above
Description : Green coal, in order to be burnt, must be (A) Heated sufficiently (B) Burnt in excess air (C) Heated to its ignition point (D) Burnt as powder
Last Answer : (C) Heated to its ignition point
Description : It is easy to detect and monitor excess air a. As oxygen not used for combustion is heated and discharged with the exhaust gases. b. Oxygen is discharged without heating c. Both a. & b. d. None of above
Last Answer : a. As oxygen not used for combustion is heated and discharged with the exhaust gases.
Description : What is the resulting pressure when one pound of air at 15 psia and 200 ˚F is heated at constant volume to 800 ˚F? A.15 psia B. 28.6 psia C. 36.4 psia. D. 52.1 psia Formula : T1/p1 = T2/p2 p2= p1T2 / T1
Last Answer : 28.6 psia
Description : When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel. A. atomisation B. carbonisation
Last Answer : Answer: B
Description : Which of the following is the best example of law of conservation of mass? [NCERT 1975] (A) 12 g of carbon combines with 32 g of oxygen to form 44 g of CO2. (B) When 12 g of carbon is ... mass remains unaltered. (D) The weight of a piece of platinum is the same before and after heating in air.
Last Answer : (A) 12 g of carbon combines with 32 g of oxygen to form 44 g of CO2.
Description : Why should a magnesium ribbon be cleaned before burning in air ? -Chemistry-10
Last Answer : Magnesium gets covered with a layer of magnesium oxide when kept in air for a long time. This layer hinders the burning of magnesium. Hence, it is to be cleaned before burning.
Description : .Identify the physical and chemical changes from the following (i)Burning of magnesium in air (ii)Electrolysis of water (iii)Tarnishing of silver spoon (iv)Sublimation of iodine -Chemistry
Last Answer : (i) Burning of magnesium in air : Chemical change (ii) Tarnishing of silver spoon : Chemical change (iii) Sublimation of iodine : Physical change (iv) Electrolysis of water to form hydrogen and oxygen is also a chemical change.
Description : State the type of chemical reactions and chemical equations that take place in the following: (i) Magnesium wire is burnt in air. (ii) Electric current is passed through water. (iii) Ammonia and hydrogen chloride gases’are mixed. -Chemistry
Last Answer : This is the Answer:
Description : Is burning magnesium in the air a chemical change?
Last Answer : Yes. Burning anything is a chemical change.
Description : Which compound is formed when a Magnesium ribbon is burnt in air? (1) Magnesium Nitrate (2) Magnesium Carbonate (3) Magnesium Oxide (4) Magnesium Nitride
Last Answer : (3) Magnesium Oxide Explanation: When Magnesium burns air it reacts with oxygen present in air to form magnesium oxide.
Description : Magnesium ribbon on burning in air produces a) magnesium oxide ,water and light c) magnesium oxide and heat b) magnesium oxide , heat and light d) magnesium oxide, water and heat
Last Answer : b) magnesium oxide , heat and light
Description : Which one of the following metals is immune to corrosion by air, water, hydrochloric acid and nitric acid; but is soluble in aqua regia? w) gold x) silver y) magnesium z) nickel
Last Answer : ANSWER: W -- GOLD