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Ques : Solve the following equations 152x-378y= 74 and 378x+152y= 604 Ans :

                                Brain                 (Study - Encephology ) # Brain is the highly specalised organ of the body. Brain develops by the enlargement of embryonic neural tube... It is presemt in the cranial cavity of the skull and forms about 98% of the central nervous system.. # Brain is protected by connective tissue membrane called MENINGES.. # In fishes, only one protective covering is present called MENINX PRIMITIVA.. # In amphibians, reptiles, birds, brain is covered by two meninges:  Inner- pia arachnoid and Outer - Duramater.. # In mammals three protective covering is present:  Inner - piamater ; Middle - arachnoid and Outer - durameter...   # Just below and above the arachnoid membrane space is present, called SUBARACHNOID and SUBDURAL respectively..  These space are filled with Cerebrospinal fluid protect the brain from mechanical injury while cerebrospinal fluid protect the brain from Mechanical shock and also helps in exchange of nutrients, gases and was

            RESPIRATORY SYSTEM (STUDY - PULMONOLOGY) » RESPIRATION IS A CATABOLIC PROCESS INVOLVING : THE BURNING OF FOOD PARTICLES IN THE PRESENCE OF OXYGEN;ELIMINATION OF CARBON DIOXIDE PRODUCED DURING THE OXIDATION; RELEASE OF ENERGY. SOME OF THE ENERGY IS STORED IN THE HIGH ENERGY BOND OF ATP MOLECULES... » Respiratry system consist of : (1) Respiratory organ. .. (2) Respiratory tract... (1) Respiratory Organ... On the basis of types of respiratory organ, there are following mode of respiration: # Skin/ cutaneous respiration - cutaneous respiration involve exchange of gases through skin, which occurs when skin is thin, moist,, highly vascular and is directly or indirectly contact with the souce of oxygen.. - This respiration can occur in both air and water... - It is exhibited by annelids, some crustaceans and amphibians .. # Buccopharyngeal respiration - like

Ques :  How much electric field will produced a charge of 1c at a distance of 1m from air? Ans : Using, this formula to find electric field  where q= 1 C ,   r = 1 m ,     So ,        

Ques :  Can I use algebraic method of solving chemical equations in 9th class of ICSE when it is not in book? Ans : We can definitely use algebraic method of solving chemical equations in 9th class of ICSE because it paper is to be held in school only. So, there is no boundation at all.  And for total surity you can easily consult with your subject teacher. 

Ques 1: If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?   Ans 1: In asexual reproduction, the reproducing cells produces a copy of their DNA through some special chemical reactions. However, this copying of DNA is not completely accurate and therefore, the newly  formed DNA has some variations.   It can be easily seen in the above figure that in asexual reproduction, very few  variations are allowed. Therefore, if a trait is present in only 10% of the total population, it is more likely that the trait has arisen recently. Hence, it can be concluded that trait B that  exists in 60% of the same population has arisen earlier than trait A.   Ques 2: How does the creation of variations in a species promote survival?   Ans 2: Sometimes for a species, the environmental conditions change so drastically(badly) so that their  survival becomes difficult. For example

Ques 4 : Which one of the following types of medicines is used for treating indigestion?   (a) Antibiotic (b) Analgesic (c) Antacid (d) Antiseptic Ans 4 : (c) Antacid is used for treating indigestion.  «« Previous question              Next question »»

Ques 3: 10 mL of a solution of Na OH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of Na OH, the amount of HCl solution (the same solution as before) required to neutralise it will be   (a) 4 mL  (b) 8mL (c) 12 mL  (d) 16 mL Ans 3 : (d) 16 mL of HCl solution will be required.  «« Previous question              Next question »»

Ques 2 : A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains   (a) Na Cl  (b) HCl  (c) L i Cl (d) K Cl Ans 2 : (b) The solution contains HCl. Egg shells contains Calcium carbonate. When C a CO 3 reacts with H Cl it releases CO 2 which turns lime water milky.  «« Previous question              Next question »»

Ques 1: A solution turns red litmus blue, its pH is likely to be   (a) 1 (b) 4 (c) 5 (d) 10 Ans 1 : (d) Bases turn red litmus blue and acids turn blue litmus red. Basic solution has a pH value more than 7 to 14. P H 14 is the most basic in nature. Since the solution turns red litmus blue, its pH is likely to be 10.   «« Chapter 1 NCERT Solution   «« Chapter 1 Additional Questions Solutions                                                Next question »»

Ques 1: Why does the colour of copper sulphate solution change when an iron nail is dipped in it?  Ans 1 : When an iron nail is dipped in a copper sulphate solution, iron (which is more reactive than copper) displaces copper from copper sulphate solution forming iron sulphate, which is green in colour. «« Previous question              Next question »»

Ques 2 : Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.   Ans 2: During the Electrolysis of water, hydrogen and oxygen is get separated by the electricity. Water (H2O) contains two parts hydrogen and one part oxygen. Since hydrogen goes to one test tube and oxygen goes to another, the amount of gas collected in one of the test tubes is double of the amount collected in the other. «« Previous question              Next question »»

Ques 3 : Identify the substances that are oxidised and the substances that are reduced in the following reactions.  (i) 4Na (s) +  O 2  (g) → 2  Na 2 O (s) (ii) Cu O (s) +  H 2  (g) → Cu (s) +  H 2 O  (l) Ans 3 : (i). Sodium (Na) is oxidised as it gains oxygen and oxygen gets reduced.  ( ii). Copper oxide (Cu O) is reduced to copper (Cu) while hydrogen (H2) gets oxidised to water (H2O). «« Previous question              Next question »»

Ques 2 : Give an example of a double displacement reaction other than the one given in Activity 1.10.  Ans 2 : Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride.     Na 2   CO 3  + C a  Cl 2  → C a  CO 3  + 2 Na Cl «« Previous question              Next question »»

Ques  1 : A solution of a substance ‘X’ is used for white washing.  (i) Name the substance ‘X’ and write its formula. (i i) Write the reaction of the substance ‘X’ named in (i) above with water. Ans  1 : (i). The substance ‘X’ is calcium oxide. Its chemical formula is Ca O.  (ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime).  «« Previous question              Next question »»

Ques 3 : Write a balanced chemical equation with state symbols for the following reactions.  (i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.  (ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water. Ans 3 : (i) Ba  Cl 2  +  Na 2   SO 4    →  Ba  SO 4    + 2 Na Cl  (ii) Na OH + H Cl → Na Cl +  H 2 O «« Previous question              Next question »»

Ques 2 : Write the balanced equation for the following chemical reactions.  (i) Hydrogen + Chlorine → Hydrogen chloride (ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride  (iii) Sodium + Water → Sodium hydroxide + Hydrogen Ans 2 : (i)  H 2  +  Cl 2  →2 H  (ii) Ba  Cl 2  +  Al 2 (SO 4) 3 →3 Ba  SO 4  + 2 Al  Cl 3 (iii) Na +  H 2 O  → Na OH «« Previous question              Next question »»

Ques 1 : Why should a magnesium ribbon be cleaned before burning in air? Ans 1: Magnesium is very reactive metal like (Na, C a, etc.). When it expose to air it reacts with oxygen to form a layer magnesium oxide (Mg O) on its surface.                  Mg +  O 2 → 2 Mg O This layer of magnesium oxide is quite stable and prevents further reaction of magnesium with oxygen. The magnesium ribbon is cleaned by sand paper to remove this layer so that the underlying metal can be used for the reaction. «« Chapter 1 NCERT Solution                                            Next question »»