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Ask QuestionPosted by Sajal Samveg 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
When a candle burns, both physical & chemical changes occur. On heating, candle wax melts and form liquid wax. It is a physical change. Since it again turns into solid wax on cooling. This is a reversible change. When a candle is burnt in air, the mass of the product is increased due to atmospheric oxygen which show a that it is a chemical change.
Posted by Sajal Samveg 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Sulphur dioxide gas changes acidifed Potassium Dichromate solution from orange to green.
Chemical reaction:
Sulphur dioxide reacts with acidified potassium Dichromate solution to give Chromium Sulphate , Poatssium sulphate and water.
3SO2(g) + K2Cr2O7(aq) +H2SO4(aq) ---------> Cr2(SO4)3 (aq) + K2SO4 (aq) +H2O(l)
Posted by Sajal Samveg 5 years, 1 month ago
- 2 answers
Sajal Samveg 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Citric acid turns potassium permanganate from purple to colourless because it is a reducing agent.
KMnO4 will oxidize citric acid to CO2 and H2O and itself will turn into almost colorless Mn(2+) (in acidic environment), or, into brown MnO2 precipitate.
OR
C6H807 + KMnO4 + H+ → 6CO2 + H2O + MnO2
Posted by Sajal Samveg 5 years, 1 month ago
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Posted by Suraj Thombre 5 years, 1 month ago
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Rounak Mishra 5 years, 1 month ago
Posted by Himesh Patidar 5 years, 1 month ago
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Sadhana Singh 5 years, 1 month ago
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Rounak Mishra 5 years, 1 month ago
Posted by Ritesh Yadav 5 years, 1 month ago
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Sajal Samveg 5 years, 1 month ago
Rounak Mishra 5 years, 1 month ago
Posted by Himesh Patidar 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Copulation is the act of mating or sexual intercourse. It involves insertion of a male's ***** into a female's ****** for the purposes of sexual pleasure, reproduction, or both.
Posted by Sakshi Srivastava 5 years, 1 month ago
- 2 answers
Yogita Ingle 5 years, 1 month ago
I = 5 A
R = 2
T = 30 minutes / 1800 sec
To Find:
E=?
Solution :
P = I²R
P = 5²2
P = 50 w ........(1)
E = P×T
E = 50×1800
E=90000 J
or
E= 90KJ
Sajal Samveg 5 years, 1 month ago
Posted by Saurav Kumar. 5 years, 1 month ago
- 3 answers
Akshar Mehta 5 years, 1 month ago
Gaurav Seth 5 years, 1 month ago
Reflection of light is the phenomenon of bouncing back of light in the same medium on striking the surface of any object.
• The two laws of reflection are:
(i) the incident ray, the reflected ray and the normal (at the point of incidence), all lie in the same plane.
(ii) the angle of reflection (<i>r</i>) is always equal to the angle of incidence (<i>i</i>)
∠<i>r</i> = ∠<i>i</i>
Yogita Ingle 5 years, 1 month ago
- The law of reflection defines that upon reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray, with respect to the normal to the surface that is to a line perpendicular to the surface at the point of contact.
- The reflected ray is always in the plane defined by the incident ray and the normal to the surface at the point of contact of the incident ray.
Posted by Shivkanya Sase 5 years, 1 month ago
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Sumesh ☺️☺️☺️ 5 years, 1 month ago
Posted by Thejessri Sathasivam 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
Haemoglobin is the respiratory pigment that transports oxygen to the body cells for cellular respiration. Therefore, deficiency of haemoglobin in blood can affect the oxygen supplying capacity of blood. This can lead to deficiency of oxygen in the body cells. It can also lead to a disease called anaemia. The average haemoglobin content of blood, irrespective of ***, is 14.5 gm per 100 mL.
</article>Posted by The_ Pj 5 years, 1 month ago
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Shivam Sharma 5 years, 1 month ago
Mayank Narang 5 years, 1 month ago
Gaurav Seth 5 years, 1 month ago
Answer
The name given to the element, by mendeleev, similar to scandium in properties was eka-boron.
In greek language eka=similar. Since eka boron showed characteristics similar to scandium.
Therefore mendeleev named scandium as eka-boron.
Posted by Ranvijay Kumar 5 years, 1 month ago
- 4 answers
Shivam Sharma 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Budding is a form of asexual reproduction where a bud or outgrowth from the end or side of the parent organism emerges and develops into a new organism. This is seen in fungi, hydra as well as in plants. Usually, the protrusion stays attached to the primary organism for a while, before becoming free. The new organism is naturally genetically identical to the parent. When yeast buds, one cell becomes two cells. When a sponge buds, a part of the parent sponge falls off and starts to grow into a new sponge.
In Hydra, a bud develops as an outgrowth due to repeated cell division at one specific site. These buds develop into tiny individuals and when fully mature, detach from the parent body and become new individuals
Posted by Sapan Ñåɏåk 5 years, 2 months ago
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Shivam Sharma 5 years, 1 month ago
Devansh Saini 5 years, 1 month ago
Kunal Kushwah 5 years, 2 months ago
Posted by Alisha. Afreen 5 years, 2 months ago
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Posted by Jiya Kumari 5 years, 2 months ago
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Shivam Sharma 5 years, 1 month ago
Gaurav Seth 5 years, 2 months ago
(d) Combination Reaction
Explanation:
Combustion is a chemical process or a reaction between Fuel (Hydrocarbon) and Oxygen. When fuel and oxygen react it releases the heat and light energy. Heat and light energy then result in the flame. So, the formula for Combustion reaction is Hydrobcarbon + Oxygen = Heat energy.
Posted by Jiya Kumari 5 years, 2 months ago
- 1 answers
Gaurav Seth 5 years, 2 months ago
A ns w e r : 4
The chemical equation for the reaction of lead sulfide with ozone follows:
By stoichiometry of the reaction:
1 mole of lead sulfide reacts with 4 moles of ozone.
So, 1 molecule of lead sulfide will react with molecules of ozone.
Or
PbS + O3 --> PbSO4
After balancing
3PbS + 4O3 --> 3PbSO4
Posted by Shubham Sharma 5 years, 2 months ago
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Kapil Agarwal 5 years, 2 months ago
Posted by Rishu Yadav 5 years, 2 months ago
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Inderjot ~~ 5 years, 2 months ago
Gaurav Seth 5 years, 2 months ago
Considering the loss of classroom teaching time due to the Covid-19 pandemic and lockdown, CBSE reduced the syllabus of classes 9 to 12 with the help of suggestions from NCERT.
The CBSE syllabus has been rationalized keeping intact the learning outcomes so that the core concepts of students can be retained.
Click on the given link for <font color="#FF6600"><font style="box-sizing: border-box;">Revised Curriculum for the Academic Year 2020-21</font></font>
<div class="panel-group" id="accordion" style="margin-bottom:5px; text-align:start; -webkit-text-stroke-width:0px"> <div class="panel panel-default" style="border:1px solid #dddddd; margin-bottom:0px; border-radius:4px"> <div class="panel-heading" style="border-bottom:0px #dddddd; padding:10px 15px; border-top-left-radius:3px; border-top-right-radius:3px; border-top-color:#dddddd; border-right-color:#dddddd; border-left-color:#dddddd"><a data-toggle="collapse" href="http://cbseacademic.nic.in/Revisedcurriculum_2021.html#collapse2" style="box-sizing:border-box; color:inherit; text-decoration:none; outline:0px; display:block; font-weight:bold">Revised Secondary Curriculum (IX-X)</a>
</div> </div> </div>
Posted by T M 5 years, 2 months ago
- 2 answers
Gaurav Seth 5 years, 2 months ago
In direct current, the current flows in one direction only. Some sources of direct current are cell, DC generator, etc. Dry cell, dry cell battery, car battery and DC generator, radio and television works only with D.C they have a device in them which convert A.C supplied to them into D.C. The DC current is the current which does not change the direction with time.
Posted by Arpita .9 5 years, 2 months ago
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Ranvijay Kumar 5 years, 2 months ago
Posted by Prashant Singh 5 years, 2 months ago
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Gaurav Seth 5 years, 2 months ago
Prenatal *** determination has been prohibited by law because of indiscriminate female foeticide. As a result of this, child *** ratio is declining at an alarming rate in some sections of our society. For a healthy society, the female-male *** ratio must be maintained.
Posted by Sarika Ale 5 years, 2 months ago
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Posted by Abhishek Kumar 5 years, 2 months ago
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Yogita Ingle 5 years, 2 months ago
Washing soda is a whitish, odourless powder. Its chemical formula is Na2CO3 and is better known as sodium carbonate.
Sodium chloride (NaCI), ammonia (NH3) and limestone (CaCO3) are raw materials used for the manufacture of washing soda by Solvay process.
At first, sodium bicarbonate is obtained which is then converted to sodium carbonate on heating. Finally, washing soda is produced by recrystallization of sodium carbonate.
- NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl
- 2 NaHCO3 → Na2CO3 + H2O + CO2
- Na2CO3 + 10H2O → Na2CO3.10H2O
Posted by Jiya Bhayana 5 years, 2 months ago
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