CBSE > Class 07 > Science | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

State few properties of acids

Posted by Sunaina Bharti 4 years, 5 months ago

2 answers

Naman Jangra 4 years, 5 months ago

1. Acids have sour taste 2. When dissolve in water, and react with metals to produce hydrogen gas. 3.turns blue litmus red 4. Acids are water soluble. 5. Acid and base react with each other to form salt and water.

0Thank You

Arunima Mishra 4 years, 5 months ago

0Thank You

ANSWER

What is the meaning of heat

Posted by Shlok Solanki 4 years, 5 months ago

CBSE > Class 07 > Science

2 answers

Jivitesh .H 4 years, 5 months ago

Heat is a form of energy. It makes other substance hotter

1Thank You

Abhinav Singh 4 years, 5 months ago

Heat is a form of energy. It makes other substance hotter

1Thank You

ANSWER

What is Euclid's

Posted by Veeru Kumar 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Sia ? 4 years, 5 months ago

Euclid, sometimes called Euclid of Alexandria to distinguish him from Euclid of Megara, was a Greek mathematician, often referred to as the "founder of geometry" or the "father of geometry". He was active in Alexandria during the reign of Ptolemy I.

0Thank You

ANSWER

Plants can make their own

Posted by Shiva Poniya 4 years, 5 months ago

CBSE > Class 07 > Science

3 answers

Divyanshi Jadon 4 years, 4 months ago

Food

1Thank You

M Harini 4 years, 5 months ago

Saapadu

0Thank You

Tanmay Das 4 years, 5 months ago

Plants can make their own food by the process of photosynthesis.

2Thank You

ANSWER

How do parasite make food

Posted by Sudarshan Rathod 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Arunima Mishra 4 years, 5 months ago

They depend on their host (other plants) for their food.

0Thank You

Piyush Rathod 4 years, 5 months ago

Search on google

0Thank You

Riya Soni 4 years, 5 months ago

They take other plant's Nutrition and make their food

0Thank You

Riya Soni 4 years, 5 months ago

They make their food from other plants/trees

0Thank You

Riya Soni 4 years, 5 months ago

Hello I am Riya

0Thank You

ANSWER

what is all steps called of Silkworm evolution please tell each step name also ? BTW I am Riya Soni class 7th in Kendriya Vidyalaya no. 4 Khatipura road hasanpura Jaipur Rajasthan

Posted by Reetu Soni 4 years, 5 months ago

CBSE > Class 07 > Science

4 answers

Sidra Ali 4 years, 5 months ago

4 they feed on mulberry leaf /any other leaf 5 they spin cocoon inside which is a pupa 6 the pupa breaks the cacoon and become a moth

0Thank You

Sidra Ali 4 years, 5 months ago

2 the eggs hatch and them the warms/ caterpillar/larvae comes out

0Thank You

Sidra Ali 4 years, 5 months ago

1 female silk moth lays egg

0Thank You

Piyush Rathod 4 years, 5 months ago

Search on google

0Thank You

ANSWER

Sandhya Kumari class 7b

Posted by Abhi... Kum@R 4 years, 5 months ago

CBSE > Class 07 > Science

2 answers

Aman Ar 4 years, 5 months ago

@royal_nawab.04 Insta

0Thank You

Aman Ar 4 years, 5 months ago

Hlw

0Thank You

ANSWER

Silk mouth in brief

Posted by Vedant Masram 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Piyush Rathod 4 years, 5 months ago

Search on google

0Thank You

ANSWER

How would you show that setting on a curd is a chemical change

Posted by Priya Batth 4 years, 5 months ago

CBSE > Class 07 > Science

2 answers

M Harini 4 years, 5 months ago

Irreversible change

0Thank You

Anuska Mukherjee 4 years, 5 months ago

SETTING OF CURD IS A CHRMICAL CHANGE BECAUSE IT CANNOT BE REVERSED

1Thank You

ANSWER

Why would some plants feed on insects

Posted by Ashwika Garg 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Sashwati Lahkar 4 years, 5 months ago

They fulfill their requirement of nitrogen from the insects. They are not able to take nitrogen from the soil. They are partial heterotrophs.

3Thank You

Lavkesh Yadav 4 years, 5 months ago

Some plants feed on insect because they have no chlorophyll so they can't make food own. So, they feed insects

3Thank You

Shikha Karnwal 4 years, 5 months ago

What

4Thank You

Yashi Bhatnagar 4 years, 5 months ago

Because these play need lot of nitrogen and his requirement not fulfilled so they eat insects

3Thank You

Virani Bansri 4 years, 5 months ago

Because they have one kind of food

1Thank You

ANSWER

Chapter 4 6 question answer

Posted by Namrata Shelko 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Saurav Suman 4 years, 5 months ago

Un to u.

2Thank You

ANSWER

What is catapiller

Posted by Shaik Shadullah Sufiyan 4 years, 5 months ago

CBSE > Class 07 > Science

3 answers

Piyush Rathod 4 years, 5 months ago

I don't know but i know what is caterpillar

0Thank You

P. Rajkishore Dora 4 years, 5 months ago

a small hairy animal with a long body and a lot of legs, which eats the leaves of plants. A caterpillar later becomes an insect with large, often colourful wings (a butterfly or a moth)

2Thank You

Lavkesh Yadav 4 years, 5 months ago

The larave other name is caterpillar and silkworm

2Thank You

ANSWER

Lichens are

Posted by Geeta Vasant Kumar Gouda 4 years, 5 months ago

CBSE > Class 07 > Science

4 answers

Sashwati Lahkar 4 years, 5 months ago

Symbiotic plants

0Thank You

Vagisha M Srivastava 4 years, 5 months ago

Symbiosis

1Thank You

Yashi Bhatnagar 4 years, 5 months ago

Types of symbiosis relationship

0Thank You

Lavkesh Yadav 4 years, 5 months ago

The relationship of algae and fungi

1Thank You

ANSWER

The most commonly used natural indicater is which

Posted by Jagjeet Singh 4 years, 5 months ago

CBSE > Class 07 > Science

4 answers

Arunima Mishra 4 years, 5 months ago

Turmeric and china rose

0Thank You

Anuska Mukherjee 4 years, 5 months ago

Litmus

0Thank You

Vaishnavi Yadav 4 years, 5 months ago

Turmeric and china rose

4Thank You

Anshika Shukla 4 years, 5 months ago

Haldi China rose

4Thank You

ANSWER

Write short note on threshing

Posted by Arjunsingh Rajpurohit 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Tiyasha Mandal 4 years, 4 months ago

Threshing is a way of separating grains from stalks by beating them on a hard rock (manually) It is also done using machines now a days.

0Thank You

ANSWER

Write one similarity and one difference between the nutrition in amoeba and human beings.

Posted by Anurag Sathe 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Naman Jangra 4 years, 5 months ago

Similarity - Both amoeba and human being follow the holozik types of nutrients Difference - Human intake food through Buccal cavity, in amoeba food is ingested through pseudopodia

1Thank You

Yashi Bhatnagar 4 years, 5 months ago

Similarity - Both amoeba and human eat food for growth, maintain their body and for multiplication Difference - Human have different organ to digest different components of food but amoeba have only food vacuole to digest food

1Thank You

Vaishnavi Yadav 4 years, 5 months ago

Similarity - Both amoeba and human being follow the holozik types of nutrients Difference - Human intake food through Buccal cavity, in amoeba food is ingested through pseudopodia

2Thank You

Soham Shinde 4 years, 5 months ago

Difference: Though amoeba and humans share the same mode of nutrition, both process the nutrients and convert them into energy in different ways. Humans have a complex digestive system, while amoeba engulfs its food and brings it deep within the cell.

1Thank You

Nitya Shukla 4 years, 5 months ago

One similarity difference between the nutrition in amoeba and human beings is that in both the cases digestive juices breaks down the complex food particles into simplest substances. One difference is that amoeba has no mouth or digestive system but human being has mouth and digestive system which is made up of many organs

1Thank You

ANSWER

What is black matter

Posted by Rudradip Das Gat 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Ayush _Kumar 4 years, 5 months ago

Dark matter can refer to any substance which interacts predominantly via gravity with visible matter (e.g., stars and planets). Hence in principle it need not be composed of a new type of fundamental particle but could, at least in part, be made up of standard baryonic matter, such as protons or neutrons.

0Thank You

ANSWER

WHAT IS IRON

Posted by Vihaan Chokshi 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Pragati Agrawal 4 years, 5 months ago

Iron is a metal that is attracted by magnet ? due to magnetic power

0Thank You

Janvi Solanki 4 years, 5 months ago

Iron is metal it can attracted by a ? magnet

1Thank You

Anshika Shukla 4 years, 5 months ago

Iron is a metal

0Thank You

Riksita Bhat 4 years, 5 months ago

Iron is a metal that is attracted by magnet

2Thank You

Swara Bhatt 4 years, 5 months ago

Iron is a metal that is attracted by magnet

1Thank You

ANSWER

Two methods by which rusting of iron can be prevented are __________ and __________

Posted by Soham Shinde 4 years, 5 months ago

CBSE > Class 07 > Science

3 answers

Pragati Agrawal 4 years, 5 months ago

Painting and Galvanisation

0Thank You

Sashwati Lahkar 4 years, 5 months ago

Painting and Galvanisation

0Thank You

Lakshita Jain 4 years, 5 months ago

The method are painting and Alloying

0Thank You

ANSWER

Another name for sodium sodium hydrogen carbonate

Posted by Shivanand Wali 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Nitya Shukla 4 years, 5 months ago

Baking soda

0Thank You

ANSWER

Iron pipes coated with zinc do not get rusted easily. (True/ False)

Posted by Soham Shinde 4 years, 5 months ago

CBSE > Class 07 > Science

3 answers

Sashwati Lahkar 4 years, 5 months ago

True

0Thank You

Iqra Girach 4 years, 5 months ago

true

0Thank You

Shivanand Wali 4 years, 5 months ago

True

1Thank You

ANSWER

Keywords of ch 4 heat solution

Posted by Best Girl 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Soham Shinde 4 years, 5 months ago

(i) fusion (ii). vapourisation (iii) temperature (iv). insoluble heavy impurities.

1Thank You

ANSWER

State similarities and differences between the laboratory thermometer and the clinical thermometer

Posted by Sahanu Jangde 4 years, 5 months ago

CBSE > Class 07 > Science

2 answers

Lavkesh Yadav 4 years, 5 months ago

Difference We give a jerk to clinical thermometer but laboratory thermometer not give the jersey

0Thank You

Lavkesh Yadav 4 years, 5 months ago

Similarities (a)Both thermometer are used to check the body temperature (b) Both are made up of glass

1Thank You

ANSWER

Chapter 6 exercise

Posted by Kanchi 🙂 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Piyush Rathod 4 years, 5 months ago

Search on google

0Thank You

Iqra Girach 4 years, 5 months ago

ncert solutions pe dhek lo

0Thank You

Ravneet Kaur 4 years, 5 months ago

Q.1.Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f) Digestion of food Ans.(a) Chemical change (b) Physical change (c) Chemical change (d) Physical change (e) Physical change (/) Chemical change Q.2.(a) Cutting a log of wood into pieces is a chemical change. (True/ False) (b) Formation of manure from leaves is a physical change. (True/ False) (c)Iron pipes coated with zinc do not get rusted easily. (True/ False) (d)Iron and rust are the same substances. (True/ False) (e)Condensation of steam is not a chemical change. (True/ False) Ans. (a)False Correct statement: Cutting a log of wood into pieces is an irreversible physical change. (b)False Correct statement: Formation of manure from leaves is a chemical change. (c) True (d)False Correct statement: Iron and rust are two different chemical substances. (e)True Q.3.Fill in the blanks in the following statements: (a) When carbon dioxide is passed through lime water, it turns milky due to the formation of . (b) The chemical name of baking soda is . (c) Two methods by which rusting of iron can be prevented are __________ and __________ (d) Changes in which only ____________ properties of a substance change are called physical changes. (e) Changes in which new substances are formed are called _____________ changes.. Ans. (a)calcium carbonate (b) sodium hydrogen carbonate (c) painting or greasing, galvanisation (d) physical (e) chemical Q.4. When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain. Ans. The reaction between baking soda and lemon juice can be given as below: Lemon juice + Baking soda ————-> C02 (bubbles) + Other substances (Citric acid) (Sodium hydrogen carbonate) (Carbon dioxide) It is a chemical change Q.5. When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place. Ans. When a candle burns, both physical and chemical changes occur: (i) Physical change: melting of wax, vapourisation of melted wax. (ii) Chemical change: Burning of vapours of wax to give carbon dioxide, heat and light. LPG is another example in which physical change occurs when LPG comes out of cylinder and is converted from liquid to gaseous state and a chemical change occurs when gas burns in air. Q.6. How would you show that setting of a curd is a chemical change? Ans. We can say that setting of curd is a chemical change because we can not get the original substance, i.e., milk back and a new substance is formed with different taste, smell and other chemical properties Q.7. Explain why burning of wood and cutting it into small pieces are considered as two different types of changes. ~ Ans. Burning of wood is a chemical change because in burning new substances are formed as Wood + Oxygen ———–> Charcoal + Carbon dioxide + Heat + Light But cutting it into small pieces is physical change because no new substance is formed. We can only reduce the size of wood. Q.8. Describe how crystals of copper sulphate are prepared. Ans. Take a cupful of water in a beaker and add a few drops of dilute sulphuric acid. Heat the water. When it starts boiling, add copper sulphate powder slowly. Continue to add copper sulphate powder till no more powder can be dissolved. .During this process continuously stir the solution. Filter the solution. Leave it for cooling. Look it after some time, you can see the crystals of copper sulphate Q.9. Explain how painting of an iron gate prevents it from rusting? Ans. It is known that for rusting the presence of oxygen and moisture is essential. Painting prevents the iron gate from coming in contact with oxygen and moisture. Q.10. Explain why rusting of iron objects is faster in coastal areas than in deserts. Ans. As content of moisture in the air in coastal areas is higher than in the air in deserts. So, the process of rusting is faster in coastal areas. Q.11. The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change- A) then it bums (Change-B). The following statements pertain to these changes. Choose the correct one. (i) Process-A is a chemical change. (ii) Process-B is a chemical change. (iii) Both processes A and B are chemical changes. (iv) None of these processes is a chemical change. Ans. (ii) Process-B is a chemical change. Q.12.Anaerobic bacteria digest animal waste and produce biogas (Change-A). The biogas is then burnt as fuel (Change-B). The following statements pertain to these changes. Choose the correct one. (i) Process-A is a chemical change. (ii) Process-B is a chemical change. (iii) Both processes A and B are chemical changes. (iv) None of these processes is a chemical change. Ans.(iii) Both processes A and B are chemical change

0Thank You

Rachit Garg 4 years, 5 months ago

Exercise Questions 1. Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f ) Digestion of food Solution: a) Chemical change b) Physical Change c) Chemical change d) Physical Change e) Physical Change f) Chemical change 2. State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook. (a) Cutting a log of wood into pieces is a chemical change. (True/False) (b) Formation of manure from leaves is a physical change. (True/False) (c) Iron pipes coated with zinc do not get rusted easily. (True/False) (d) Iron and rust are the same substances. (True/False) (e) Condensation of steam is not a chemical change. (True/False) Solution: a) False b) False c) True d) False e) True 3.Fill in the blanks in the following statements: (a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________. (b) The chemical name of baking soda is _________. (c) Two methods by which rusting of iron can be prevented are _________ and _________. (d) Changes in which only _________ properties of a substance change are called physical changes. (e) Changes in which new substances are formed are called _________ changes. Solution: (a) When carbon dioxide is passed through lime water, it turns milky due to the formation of Calcium carbonate. (b) The chemical name of baking soda is Sodium hydrogen carbonate. (c) Two methods by which rusting of iron can be prevented are painting and galvanization. (d) Changes in which only physical properties of a substance change are called physical changes. (e) Changes in which new substances are formed are called chemical changes. 4. When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain. Solution: When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a carbon dioxide gas. This is a chemical change. Lemon juice + Baking soda → Carbon dioxide + other substances 5. When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place. Solution: Candle Burning Physical change is melting of wax: The chemical change is the burning of gas with the evolution of CO2 Digestion of Food Physical change is the breakdown of larger food molecules to simpler ones The chemical change is the digestion of food by the action of HCl and enzymes. 6. How would you show that setting of curd is a chemical change? Solution: The setting of curd is a chemical change because curd cannot be turned back to milk. The properties of milk and curd are different. 7. Explain why burning of wood and cutting it into small pieces are considered as two different types of changes. Solution: Cutting of wood is a physical change as it does not change the nature of the wood. On the other hand, burning of wood is a chemical change as wood is converted to charcoal with the liberation of CO2. 8. Describe how crystals of copper sulphate are prepared. Solution: Crystals of copper sulphate are prepared using the crystallization method, which is described as follows Take a cupful of water in a beaker. Add a few drops of dilute sulphuric acid to this. Heat the water and when it starts boiling, add copper sulphate powder while still stirring. Add the copper sulphate powder till the solution becomes saturated. Filter into a china dish and allow it to cool. The solution should be kept undisturbed. Slowly, the crystals of copper sulphate separate out. 9. Explain how painting of an iron gate prevents it from rusting Solution: Rusting of iron requires contact with water (moisture) and oxygen. By painting an iron gate, we prevent the contact between iron, Oxygen and water (moisture), this helps in preventing rusting of iron. 10. Explain why rusting of iron objects is faster in coastal areas than in deserts. Solution: Rusting of iron requires contact with water (moisture) and oxygen. In coastal areas, humidity is more in comparision to that in deserts; hence, rusting of iron objects is faster in coastal areas than in deserts. 11. The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exist as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (Change – B). The following statements pertain to these changes. Choose the correct one. (i) Process – A is a chemical change. (ii) Process – B is a chemical change. (iii) Both processes A and B are chemical changes. (iv) None of these processes is a chemical change Solution: The answer is (ii) Process – B is a chemical change. 12. Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one. (i) Process – A is a chemical change. (ii) Process – B is a chemical change (iii) Both processes A and B are chemical changes. (iv) None of these processes is a chemical change Solution: Answer is (iii) Both processes A and B are chemical changes.

0Thank You

Keya .V. Gaudani 4 years, 5 months ago

Noob

1Thank You

ANSWER

What is magnetic effect of electric current?

Posted by Kanav Singh 4 years, 5 months ago

CBSE > Class 07 > Science

1 answers

Soham Shinde 4 years, 5 months ago

The magnetic effect of electric current is known as electromagnetic effect. It is observed that when a compass is brought near a current carrying conductor the needle of compass gets deflected because of flow of electricity. This shows that electric current produces a magnetic effect.

0Thank You

ANSWER

Tell about viili whare it is located

Posted by Sudhanshu Singh 4 years, 5 months ago

CBSE > Class 07 > Science

3 answers

Yashi Bhatnagar 4 years, 5 months ago

The small intestine have thousands of finger like outgrowth this called villi. It is locate in the inner walls of small intestine

1Thank You

Vaishnavi Yadav 4 years, 5 months ago

Villi are the finger like-like projection and out growth they are present in small intestine of our digestive system . Villi increase the surface area to absorption of the digested food

0Thank You

Ravneet Kaur 4 years, 5 months ago

Villi are small finger-like projections found inside the inner walls of the small intestine. They v increase the surface area for absorption of the digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villiabsorbs the digested food materials

0Thank You

ANSWER

Where is bile producted ??

Posted by Priyanshi 6232 4 years, 5 months ago

CBSE > Class 07 > Science

4 answers

Sashwati Lahkar 4 years, 5 months ago

Gall bladder

0Thank You

Yashi Bhatnagar 4 years, 5 months ago

Bile juice secreted in liver

0Thank You

Aksh Gairola 4 years, 5 months ago

0Thank You

Varchasva Dixit 4 years, 5 months ago

Bile juice is produced in gall bladder

1Thank You

ANSWER

Silk fibre is obtained from:

Posted by Yash Gojiya 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Yashi Bhatnagar 4 years, 5 months ago

Silk obtained from cocoon of the silk mouth

0Thank You

Nitya Shukla 4 years, 5 months ago

Cocoon

0Thank You

Samar Sinha 4 years, 5 months ago

Silkworm

0Thank You

Keya .V. Gaudani 4 years, 5 months ago

Silworm

0Thank You

Simran Kumari 4 years, 5 months ago

Silkworm

2Thank You

ANSWER

what is the process of making wool?

Posted by Poonam Agrawal 4 years, 5 months ago

CBSE > Class 07 > Science

5 answers

Yashi Bhatnagar 4 years, 5 months ago

Shearing - Scouring - Sorting - Cleaning of burrs - Dyeing - Rolling

0Thank You

Ishi Kumar 4 years, 5 months ago

Step 1: Breeding the Sheep ? Step 2: Shearing a Sheep ? Step 3: Scouring (cleaning ?) the wool fibres Step 4: Sorting according to length, texture, quality, etc. Step 5: Picking out the burrs Step 6: Dying them in beautiful colours Step 7: Spinning them into yarn ? Step 8: Weaving the fibres into fabric.

2Thank You

Harsh Kumar 4 years, 5 months ago

shearing scouring sorting removal of burrs dyeing spinning

0Thank You

Samar Sinha 4 years, 5 months ago

1. Shearing of wool ?. 2. Scouring in tanks(nowadays in machines also). 3. Picking out burres. 4. Dyeing (colouring). 5. Rolling into yarn.

0Thank You

Shreya Kumari 4 years, 5 months ago

1 shearing a sheep ? 2 scoring the tanks 3 scoring by machine 4 rolling into yarn ?

2Thank You

ANSWER

Best app for C.B.S.E.