Ask questions which are clear, concise and easy to understand.
Ask QuestionPosted by Good Student 5 years, 5 months ago
- 2 answers
Gaurav Seth 5 years, 5 months ago
A mixture or an alloy of mercury with a number of metals or alloys such as sodium as well as with some non-metals is known as amalgam.
Uses:
1. Sodium is highly reactive metal and therefore it is difficult to transport. To lower its reactivity, it is mixed with mercury.
2. Dental amalgam is a mixture of mercury and a silver-tin alloy and is used for fillings in teeth.
Amalgam fillings are often known as “silver fillings.” Dental amalgam is a mixture of mercury, silver, tin and copper. Mercury, which makes up about 50% of the compound, binds the metals together to provide a strong, durable filling.
Posted by Good Student 5 years, 5 months ago
- 1 answers
Gaurav Seth 5 years, 5 months ago
Alloys are homogeneous mixtures of two or more metals or a metal and a non metal.
They are prepared in the following ways:
(i) Melting the primary metal.
(ii) Dissolving the other elements in a definite proportion and then cooling them to room temperature.
Constituents and uses of the alloys are:
1. Brass: It is an alloy of copper and zinc
Uses: In making utensils and scientific instruments.
2. Bronze: It is an alloy of copper and tin
Uses: In making statues and medals.
3. Solder: It is an alloy of lead and tin
4. Stainless steel: alloy of Iron
Posted by Bhagirathi Suna 5 years, 5 months ago
- 2 answers
Yogita Ingle 5 years, 5 months ago
- Pepsin is an enzyme which acts only in acidic medium. Trypsine is an enzyme which acts in alkaline medium.
- Pepsin is secreted by gastric juice. Trypsin secreted by pancreatic juice.
- Pepsin is secreted in stomach, Trypsin is secreted in small intestine.
- Pepsin is situated in gastric glands, Trypsin is situated in pancreas
Sana(Silent Love).. ?? 5 years, 5 months ago
Posted by Tanya Chawla 5 years, 5 months ago
- 2 answers
Gaurav Seth 5 years, 5 months ago
Wearing a face mask or other covering over the mouth and nose reduces the forward distance traveled by an exhaled breath by more than 90 percent.
face masks combined with other preventive measures, such as frequent hand-washing and social distancing, help slow the spread of the disease.
Ashwin Gupta 5 years, 5 months ago
Posted by Good Student 5 years, 5 months ago
- 1 answers
Gaurav Seth 5 years, 5 months ago
(i) Extraction of copper metal - Copper glance (Cu2S):
1. Concentration of the ore (removal of unwanted metals and gangue to purify the ore) is done by Froth floatation method as it is a sulphide ore.
2. Roasting: Copper glance (Cu2S) is roasted in the presence of air. Roasting turns copper glance (ore of copper) into copper (I) oxide.
3. Reduction: Copper oxide is then heated in the absence of air. This reduces copper (I) oxide into copper metal.
4. Refining impure metal: The reduced metal is purified by electrolytic refining method.
Electrolysis of copper from copper sulphate solution (electrolyte) is done using copper electrodes. The crude copper serves as anode while a thin sheet of pure copper serves as cathode.
The electrolyte consists of an acidic solution of CuSO4. Applying suitable voltage to the electrodes causes,
oxidation of copper metal at the anode (Cu -----> Cu2+ + 2e) and
reduction of Cu2+ to form copper metal at the cathode (Cu2+ + 2e -------> Cu).
As the anodes (impure copper) dissolve away, the cathodes on which the pure metal is deposited grow in size.
The impurities in the copper anode which are more active than copper are readily oxidized at the anode but do not plate out at the cathode because their reduction potentials are more negative than that for Cu2+.
Posted by Akshat Kashyap 5 years, 5 months ago
- 2 answers
Yogita Ingle 5 years, 5 months ago
Metal carbonates and Metal Hydrogencarbonates reacts with acids and produces corresponding metal salt, carbon dioxide and water.
Let us consider the reaction of sodium carbonate with dilute HCl. The reaction proceeds in the following manner.
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Posted by @S(Raj)Àĺì ???? 5 years, 5 months ago
- 2 answers
Sana(Silent Love).. ?? 5 years, 5 months ago
Posted by Jagadish Yadav 5 years, 5 months ago
- 1 answers
Meghna Thapar 5 years, 5 months ago
The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. The pericardial sac has two layers, a serous layer and a fibrous layer. It encloses the pericardial cavity which contains pericardial fluid. The pericardium is a thin sac that surrounds your heart. It protects and lubricates your heart and keeps it in place within your chest. Problems can occur when the pericardium becomes inflamed or fills with fluid. The swelling can damage your heart and affect its function. The pericardium is composed of three membranous layers that encircle the exterior of the heart: the outer fibrous pericardium, the middle parietal pericardium, and the inner epicardium (also referred to as the visceral pericardium).
Posted by Good Student 5 years, 5 months ago
- 1 answers
Meghna Thapar 5 years, 5 months ago
Metals that aren't very reactive are placed low in the reactivity series. These metals can be reduced to metals by heating alone. For example, Mercury is procured from its ore, cinnabar (HgS), by the process of heating. Copper can also be obtained from its sulphide ore (Cu2S) by heating. Metals more reactive than carbon, such as aluminium, are extracted by electrolysis, while metals less reactive than carbon, such as iron, may be extracted by reduction with carbon. As gold is so unreactive, it is found as the native metal and not as a compound. It does not need to be chemically separated.
Posted by Frisha Kamboj 5 years, 5 months ago
- 2 answers
Deepa Kumari 5 years, 5 months ago
Avni Jain 5 years, 5 months ago
Posted by Ram Prakash Dewasi 5 years, 5 months ago
- 1 answers
? Pranali.A.P ? 5 years, 5 months ago
Posted by Student ✍️✍️✍️ 5 years, 5 months ago
- 1 answers
Deepa Kumari 5 years, 5 months ago
Posted by Good Student 5 years, 5 months ago
- 2 answers
Yogita Ingle 5 years, 5 months ago
Atomic number of Sodium (Na) – 11
Electronic configuration of Sodium – 1s2 2s2 2p6 3s1
It has one valence electron, it will lose one electron to get octet configuration
Atomic number of Oxygen (O) – 8
Electronic configuration of Oxygen – 1s2 2s2 2p4
It is two electrons short of octet configuration, thus it will gain two electrons.
During the bond formation between Sodium and Oxygen, two Sodium atoms loses one electron each to Oxygen atom.
2 Na -2e- → 2Na+
O + 2e- → O-2
2Na+ + O-2 → Na2O
Atomic number of Magnesium (Mg) – 12
Electronic configuration of Magnesium – 1s2 2s2 2p6 3s2
It has two valence electrons, it will lose two electrons to get octet configuration
Atomic number of Oxygen (O) – 8
Electronic configuration of Oxygen – 1s2 2s2 2p4
It is two electrons short of octet configuration, thus it will gain two electrons.
During the bond formation between Magnesium and Oxygen, one Magnesium atom loses two electrons to Oxygen atom.
Mg -1e- → Mg2+
O + 2e- → O-2
Mg+2 + O-2 → MgO
Posted by Suryansh Singh 5 years, 5 months ago
- 2 answers
Gaurav Seth 5 years, 5 months ago
They are analogus because they have different structure i.e. humans have complete eye but planaria only have light detcting spots but they perform the same function of seeing
Posted by Priyanshu Kumar 5 years, 5 months ago
- 4 answers
Srishti Gupta 5 years, 5 months ago
Gaurav Seth 5 years, 5 months ago
- A spherical mirror, whose reflecting surface is curved inwards, i.e. faces towards the centre of the sphere, is called a concave mirror.
Surya 5 years, 5 months ago
Posted by Bharat Kol 5 years, 5 months ago
- 1 answers
Gaurav Seth 5 years, 5 months ago
CONCAVE MIRRORS;
1. They always produce real and inverted images except when an object is placed between the mirror pole and the focus which gives erect virtual images. (for real objects)
2. They produce magnified, diminished and same size images.
3.A parallel beam of incident light is concentrated on its focus and thus such a mirror is called a convergent mirror. Also a light source placed at the focus produces a parallel light beam.
4.Sign convention: The focal length and radius of curvature are taken as negative.
Posted by Surya 5 years, 5 months ago
- 3 answers
Posted by Monesh Kurre 5 years, 5 months ago
- 1 answers
Meghna Thapar 5 years, 5 months ago
The inflorescence
A flower is a modified shoot wherein the shoot apical meristem changes to floral meristem. The arrangement of flowers on thefloral axis is termed as inflorescence. ... In cymose type of inflorescence, the main axis terminates in a flower; the flowers are borne in a basipetal order. Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits.
Posted by .. .... 5 years, 5 months ago
- 1 answers
Posted by .. .... 5 years, 5 months ago
- 1 answers
Amruta Kulagod 5 years, 5 months ago
Posted by .. .... 5 years, 5 months ago
- 4 answers
Posted by Avni Jain 5 years, 5 months ago
- 1 answers
Meghna Thapar 5 years, 5 months ago
Plaster of Paris should be stored in a moisture-proof container because when plaster of Paris come in the presence of water it forms gypsum giving a hard solid mass which is ultimately useless after some time. Plaster of Paris in contact with moisture (water) changes to solid hard mass, gypsum. Therefore, it gets wasted. Hence it should be stored in moisture proof containers.
Posted by @S(Raj)Àĺì ???? 5 years, 5 months ago
- 3 answers
Posted by Avni Jain 5 years, 5 months ago
- 3 answers
Gaurav Seth 5 years, 5 months ago
A neutralization reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form a salt and water as products.
In a neutralization reaction, there is a combination of H+ ions and OH– ions which form water. A neutralisation reaction is generally an acid-base neutralization reaction.
Bharat Kohli 5 years, 5 months ago
Posted by ?Røhån? ☺️Thåkùr? 5 years, 5 months ago
- 2 answers
Posted by Drift? Boi? 5 years, 5 months ago
- 1 answers
Posted by .. .... 5 years, 5 months ago
- 5 answers
Drift? Boi? 5 years, 5 months ago
Posted by Tannu Raj 5 years, 5 months ago
- 2 answers
Avni Jain 5 years, 5 months ago
Posted by Avni Jain 5 years, 5 months ago
- 2 answers
Drift? Boi? 5 years, 5 months ago
myCBSEguide
Trusted by 1 Crore+ Students
Test Generator
Create papers online. It's FREE.
CUET Mock Tests
75,000+ questions to practice only on myCBSEguide app
Deepa Kumari 5 years, 5 months ago
0Thank You