User:Rana rony

Enjoy thinking about the following: 1-	Although iron has greater number of valence electrons that titanium, yet the latter is harder that the former; suggest a reason 2-	Although the electronic configuration of manganese ion in KMnO4 ends with completely filled 3d sublevel, yet it is coloured; clarify. 3-	Nitrate salts make no reaction with acidified potassium dichromate; rationalize. 4-	When Iron II oxide react with dilute or conc. acids, the product is iron II and not iron III salt; comment. 5-	Lithium is the only alkali metal which prefers to react with nitrogen in air; explain why. 6-	You have two samples of alloys made from iron and carbon; one is interstitial alloy and the other in intermetallic one. Suggest two methods to differentiate practically between them. 7-	Although most of the acids are colorless, nitric acid exhibits different behaviours, it is colorless at low temperatures, yellowish liquid at room temperature and almost reddish at higher degrees; propose a mechanism. 8-	Free iron exists only in volcanoes and meteorites; why only in volcanoes and meteorites? 9-	How can you prepare potassium peroxide from potassium permanganate (with balanced equations) ? 10-	How can you differentiate practically between ammonium nitride and ammonium nitrite (by two different methods) ? 11-	What is the effect of concentrated nitric acid on iron III chloride ? 12-	How can you prepare magnesium aluminate from mixed ore ? 13-	Iron reacts with all dilute acids to give iron II salt, except with nitric acid with which it gives iron III salt; why ? 14-	Decide whether manganese II sulphate is colored or colorless and explain how did you know? 15-	Can you write the equation which illustrates the reaction of acidified potassium permanganate with sodium nitrite in absence of conc sulphuric acid. 16-	May you suggest the role of sulphuric acid in the reaction in question 15 ? 17-	Write a chemical equation between nonmetal has red colour with an element exhibits photoelectric property. 18-	A sample of sodium metal is left in air for a while, it is covered with a white layer .. Rationalize ? 19-	How can you prepare nickel II sulphate from Nickel metal ? 20-	How can you prepare chromium from nickel chrome alloy ? 21-	How many mole nickel is found in 1 gm nickel-chrome alloy ? 22-	How can you differentiate practically (not by odour) between water and dimethyl formamide (this is colorless organic solvent) 23-	How can you prepare phosphonium phosphate from phosphorous ? 24-	Hydro peroxide decomposes as follows: 2H2O2 = 2H2O + O2. What is the volume of oxygen gas produced by decomposition of 25 % hydrogen peroxide solution ? 25-	0.5 gm of hydrated copper II sulphate is dissolved in hot water. When we add caustic soda solution to this solution, a black ppt. is obtained after boiling equals 0.159 gm. Calculate the no. of water of crystallization in the hydrated sample. 26-	Write down the balanced chemical equation which illustrates the reaction between conc. sulphuric acid on a mixture of Iron II sulphate and ammonium nitrate solution; then clarifies whether it this is an oxidation/reduction reaction. 27-	 A sample of salt its cation is monovealent and is isolelectronic with the nitride ion, and its anion contains the only good conductor nonmetal. A sample of this salt, 5.751g, was heated strongly till constant weight. The remaining weight was 2.130g. Calculate the percentage of water crystallization, the number of water molecules, and write the molecular structure of washing soda. 28-	What is the reaction product between the strongest oxidizing agent in period four with the most powerful reducing gent in 5th period of the periodic table. 29-	Afretinic acid (can replace, less acidic, and has higher boiling point than, can replace, more acidic, and has higher boiling point than, can't replace, more acidic, and has lower boiling point than, can't replace, less acidic, and has the same boiling point like) Shaitatinic acid. 30-	You are provided with four test tubes filled with concentrated solutions of hydrochloric, nitric, sulphuric, and phosphoric acids. Explain the steps you may use to differentiate between the aforementioned acids. 31-	Arrange the following steps to obtain iron II sulphate from iron III sulphate: neutralization, reduction, double substitution, thermal decomposition, and basification. 32-	How can you prepare chlorine gas from sodium chlorate ? 33-	Explain how can you use any material you studied in this course to make secret ink and explain how to train an agent to use it. 34-	What is the mass of an element in the 4th period, slightly stable, and forms to weak acidic oxides when reacts with oxygen, in 1 gram of its ore ? 35-	Chemistry and physics are two integrative sciences. Give two examples to clarify how each science can be used to do something in the other one. 36-	What is the group number of the element which has 12 electron in the 3rd energy level ? 37-	Ammonia gas has no effect on alcoholic phenol phthalene solution; however it turns aqueous solution of litmus into red. Comment. 38-	What is the reaction product of excess ammonium hydroxide solution and aluminum chloride solution 39-	 When an excess amount of 0.25 molar nitric acid is added to 6 ml ammonium hydroxide solution, the extra acid needs 5 ml of 0.4 molar limestone for complete neutralization. Calculate the number of mole of caustic potash which is equivalent to the number of mole of the starting ammonium hydroxide solution 40-	Make a problem with your own numbers to calculate the number of water molecules of crystallization in limonite ore 41-	Predict the value of the diameter of the interspaces between iron metals in a piece of iron if you know that the bond length in the major component in natural gas is 1.6 Angstrom, that between in the gas whose the lowest density is 0.7 Angstrom. 42-	From your chemical studies, if you were provided with a textile item and asked to make it waterproof, what should be the chemical composition of the substance you may use for this purpose. 43-	From your study in chemistry, if you want to invent a poison which can not be detected by anatomy of the dead body, can you suggest something. 44-	If you are an economist, and asked to suggest a new method (based on your chemistry background) with the maximum benefits and minimum cost to prepare phosphoric acid from one of the ores of phosphorous. 45-	Calculate the volume of liquid water which is found in 0.15 mole water.