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The process of removal of waste produced in the cell is known as ___________

Posted by Aafiya Sadiq 5 years, 2 months ago

CBSE > Class 07 > Science

2 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's the correct answer..... " The process of removal of wastes produced in the cells of the living organisms is called excretion. The parts involved in excretion forms the excretory system. "

Yogita Ingle 5 years, 2 months ago

The process of removal of wastes produced in the cells of the living organisms is called excretion. The parts involved in excretion forms the excretory system.

ANSWER

CBSE Class–VII Science NCERT Solutions CHAPTER-05 ACIDS, BASES AND SALTS Question 1. State differences between acids and bases. Answer: AcidsBases(i) Acids are sour in taste.(i) Bases are bitter in taste.(ii) It turns litmus paper red.(ii) It turns litmus paper blue.(iii) It doesn't change the colour of turmeric indicator.(iii) It changes the colour of turmeric indicator to red.(iv) It doesn't feel soapy on touching.(iv) It feels soapy on touching. Question 2. Ammonium is found in many household products, such as window cleaners. it turns red litmus blue. What is its nature? Answer: Ammonia has basic nature. Question 3. Name the source from which litmus solution is obtained. What is the use of this solution? Answer: Lichens. It is used as indicator to determine whether the given solution is acidic or basic. Question 4. Is the distilled water acidic, basic or neutral? How would you verify it? Answer: Distilled water is neutral.It can be verified with the help of red and blue litmus paper. It shows no change with both kind of litmus paper. Question 5. Describe the process of neutralization with the help of an example. Answer: The process in which an acid reacts with a base to form salt and water is known as neutralisation reaction. The reaction is given below, The reaction can be written as: Hydrochloric acid(HCl) + Sodium hydroxide(NaOH) → Sodium Chloride(NaCl) + Water (H2O) Question 6. Mark ‘T’ if the statement is true and ‘F’ if it is false: (i) Nitric acid turns red litmus blue. (T/F) (ii) Sodium hydroxide turns blue litmus red. (T/F) (iii) Sodium hydroxide and hydrochloric acid neutralise each other and forms salt and water. (T/F) (iv) Indicator is a substance which shows different colours in acidic and basic solutions. (T/F) (v) Tooth decay is caused by the presence of a base. (T/F) Answer: (i) F (ii) F (iii) T (iv) T (v) F Question 7. Dorji has a few bottles of soft drink in his restaurant. But, unfortunately these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink; another wants basic and third one wants neutral drink. How will Dorji decide which drink it to be served to whom? Answer: He can decide by the use of indicator. If the sample of drink turns red litmus blue, it is basic. If it does not turn blue litmus red, it is acidic. If it does not affect litmus, it is neutral. Question 8. Explain why: (a) An antacid tablet is taken when you suffer from acidity. (b) Calamine solution is applied on the skin when ant bites. (c) Factory waste is neutralised before disposing it into the water bodies. Answer: (a) Antacids are nothing but bases. When there is excess of acid in stomach antacid tablet neutralize the acids and relieve us. (b) Ant injects an acid during bite which causes the burning sensation. Calamine solution is basic in nature. It neutralises the acid and relieves from the pain. (c) Factory wastes contain both acidic and basic substances. These are harmful for the organisms living in water. So, these are should be neutralized before disposing. Question 9. Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator. Answer: Dip the turmeric indicator in each liquids. The liquid in which the colour of turmeric indicator changes to red is basic in nature i.e. sodium hydroxide. Since, we already identified sodium hydroxide. We will pour the sodium hydroxide in other two bottles. The liquid which get warm after pouring the sodium hydroxide(base) in it is of hydrochloric acid as heat gets evolved in the neutralisation process. The last one which shows no effect is liquid of sugar solution. Question 10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain. Answer: The above solution could be a base or a neutral solution because blue litmus paper doesn't change its colour in the neutral as well as basic solution. Question 11. Consider the following statements: (a) Both acids and bases change colour at all indicators. (b) If an indicator gives a colour change with an acid, it does not give a change with abase. (c) If an indicator changes colour with a base, it does not change colour with an acid. (d) Change of colour in an acid and a base depends on the type of the indicator. Which of these statements are correct? (i) All four (ii) a and b (iii) b and c (iv) only d. Answer: (iv) only d. IS EVERY ANSWER CORRECT

Posted by Swaraj Jena 5 years, 2 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

Why do winter monsoon winds bring a small amount of amount of rain

Posted by Rk Kagadi 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's the correct answer...... " Winter monsoons bring small amount of rain in southern part of India. It is because the Himalaya prevent much of the wind and moisture of monsoon from reaching the coast. "

Chag Kavyaa 5 years, 2 months ago

Winter monsoons bring small amount of rain in southern part of India because the Himalaya prevent much of the wind and moisture of monsoon from reaching the coast I hope it will absolutely help you !!

Aafiya Sadiq 5 years, 2 months ago

Winter monsoons bring small amount of rain in southern part of India because the Himalaya prevent much of the wind and moisture of monsoon from reaching the coast. Hope it helps you!!!

ANSWER

What is meant by Neutral Substance ? Give Examples

Posted by Deepanshu 5 years, 2 months ago

CBSE > Class 07 > Science

4 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's the correct answer.... " Neutral substance are those substances which are neither acidic nor basic. The neutral substances that are the most well known are: water, table salt, sugar and cooking oil. "

Yash Thorat 5 years, 2 months ago

The substance which is not acidic or basic is called neutral substance ex.sugar and water solution

Chag Kavyaa 5 years, 2 months ago

Neutral substance are those which are neither acidic nor basic. The neutral substances that are the most known example are salt ,sugar,oil ( cooking )

Gaurav Seth 5 years, 2 months ago

Neutral substance are those which are neither acidic nor basic. The neutral substances that are the most well known are: water, table salt, sugar and cooking oil. Cooking oil is a neutral substance.

ANSWER

Tell the life cycle of silk worm.

Posted by Palak J 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

The female silk moth lays eggs. The larvae also known as caterpillar or silkworm hatches out from the egg and grows in size. As soon as the caterpillar gets ready to develop into pupa, it first weaves a net to hold itself and swings its head from side to side in the form of the figure of eight (8).

During these movements the caterpillar secretes fibre made of a protein that hardens on exposure to air and becomes silk fibre. The caterpillar soon covers itself completely by a covering of silk fibres known as cocoon. The further development of the moth continues inside the cocoon. Silk fibres are used for weaving silk cloth.

ANSWER

Why we breathe so faster by running or doing exercises for a long time of period.

Posted by Palak J 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

When the athlete runs in the race, his body needs more oxygen. His rate of breathing increases so that more oxygen can be supplied to the body. This is the reason, an athlete needs to breathe faster and deeper than usual; after finishing the race.

ANSWER

What is atutrops

Posted by Anushka Semwal 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your correct answer....." Organisms that prepare their own food using simple substances are called autotrophs. For example, green plants. "

Anjali Jindal 5 years, 2 months ago

Organisms that prepare their own food using simple substances are called autotrophs. Like green plants

Tejasvi . 5 years, 2 months ago

Plants are autotrophs as they prepare their food themselves

ANSWER

The odometer of a car shows 356 km when the clock shows the time 9:00 a.m. What is the distance moved by the car , if at 11:00 a.m the odometer reading has changed to 426 km? Also calculate the speed of the car in km/h. Yaar please please please please please please please tell ????

Posted by Tejasvi . 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer... " Given Initial reading of odometer = 57321.0 km Final reading of odometer = 57336.0 km Initial Time = 8:30 AM Final Time = 8:50 AM We know that Odometer measure the distance travelled by the car So Total distance covered by car= Final reading of odometer - Initial reading of odometer =57336.0 - 57321.0 = 15.0 km Total time taken by Car = Final Time - Initial Time =8:50 AM - 8:30 AM = 20 minutes= 20/60 hrs. = 1/3 hrs. Now Speed of the car is defined as = Total distance covered/Total time taken = 15.0/20 = 0.75 km/min Also Speed of the car in km/hr. =15/ (1/3) = 45 km/hr. "

Chag Kavyaa 5 years, 2 months ago

35 km/h is your answer hope it helps you

Deepanshu 5 years, 2 months ago

35 km/h

ANSWER

The odometer of a car shows 356 km when the clock shows the time 9:00 a.m. What is the distance moved by the car , if at 11:00 a.m the odometer reading has changed to 426 km? Also calculate the speed of the car in km/h

Posted by Tejasvi . 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer... " Given Initial reading of odometer = 57321.0 km Final reading of odometer = 57336.0 km Initial Time = 8:30 AM Final Time = 8:50 AM We know that Odometer measure the distance travelled by the car So Total distance covered by car= Final reading of odometer - Initial reading of odometer =57336.0 - 57321.0 = 15.0 km Total time taken by Car = Final Time - Initial Time =8:50 AM - 8:30 AM = 20 minutes= 20/60 hrs. = 1/3 hrs. Now Speed of the car is defined as = Total distance covered/Total time taken = 15.0/20 = 0.75 km/min Also Speed of the car in km/hr. =15/ (1/3) = 45 km/hr. "

Deepanshu 5 years, 2 months ago

35 km/h

Tejasvi . 5 years, 2 months ago

Yaar some one please please please tell

ANSWER

What is the meaning of Neutarlisation / indigestion

Posted by Vivek Rawat 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

Neutralisation in Everyday Life

Indigestion

Our stomach contains hydrochloric acid. It helps us to digest food. But too much of acid in the stomach causes indigestion.Sometimes indigestion is painful. To relieve indigestion, we take an antacid such as milk of magnesia, which contains magnesium hydroxide. It neutralises the effect of excessive acid

ANSWER

Name two bases and their sources.

Posted by Anjali Roy 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Gaurav Seth 5 years, 2 months ago

<th>Some Common Bases</th> <th>Uses</th>

sodium hydroxide, NaOH	Used in the manufacture of soaps and detergents and as the main ingredient in oven and drain cleaners.
potassium hydroxide, KOH	Used in the production of liquid soaps and soft soaps. Used in alkaline batteries.

ANSWER

Meena has four solutions among which one is Acidic in nature. She wants to identify the Acidic solution using a litmus paper. Which of these observations would help identify the Acidic solution? (a) Place blue litmus in the solution and see if it turns white. (b) Place red litmus in the solution and see if it turns white. (c) Place blue litmus in the solution and see if it turns red. (d) Place red litmus in the solution and see if it turns blue.

Posted by Tejasvi . 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

S Balamani Kanta Reddy 8A 5 years, 2 months ago

Option C because acid changes blue litmus into red

ANSWER

What is spectrum and how is it formed?

Posted by Shreyan Bothra 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

The band of seven colours dispersed by a glass prism is known as a spectrum.

Visible light or white light is made up of seven colours. The light waves of different colours vary in their frequency and wavelengths. When a white light is made incident on a glass prism, it undergoes refraction. The prism splits the incident white light into a band of colours. The higher frequency (lower wavelength) violet light travels slower or refracts more than the lower frequency (higher wavelength) red light. Likewise the other colour light waves bend with respect to the incident white light as they pass through the prism.

Thus, the rays of different colours emerge alone and become distinct. This band of the coloured components of a light beam is called its spectrum. The sequence of colours from bottom to top is VIBGYOR (Violet, Indigo, Blue, Green, Yellow, Orange and Red).

ANSWER

Short answer of Describe how the crystals of copper sulphate are prepared

Posted by Prathmesh Charode 5 years, 2 months ago

CBSE > Class 07 > Science

2 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer...... " Crystallization is the process by which we can obtain crystals of copper sulphate. In this process, a few drops of dilute sulphuric acid is added to water. The water is then boiled & as it starts boiling, copper sulphate powder is added with stirring. The powder must be added on till the solution becomes saturated. Afterwards, it is filtered into a china dish and allowed to cool, undisturbed. After some time the crystals of copper sulphate separate out. "

Yogita Ingle 5 years, 2 months ago

Crystallization is the process by which we can obtain crystals of copper sulphate. In this process, a few drops of dilute sulphuric acid is added to water. The water is then boiled & as it starts boiling, copper sulphate powder is added with stirring. The powder must be added on till the solution becomes saturated. Afterwards, it is filtered into a china dish and allowed to cool, undisturbed. After some time the crystals of copper sulphate separate out.

ANSWER

What is a Gender

Posted by Sudarshan , Munabhai Aware 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

The way each society perceives what a 'man' is and what a 'woman' is, and what their different roles and responsibilities are, is called gender. It is more than the biological difference between men and women.

ANSWER

List the similarities and differences between aerobic and anaerobic respiration

Posted by Prathmesh Charode 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

Similarity:
(i) In both aerobic and anaerobic respiration, food is broken down to release energy.
(ii) Both take place inside cells.
(iii) Both produce byproducts.
Differences:
Aerobic Respiration Anaerobic Respiration
(i) It takes place in the presence of oxygen. (i) It takes place in the absence of oxygen.
(ii) Energy is released in higher amount. (ii) Energy is released in lesser amount.
(iii) It is a slow process. (iii) It is a fast process.
(iv) Examples: Animals and plants cells. (iv) Examples: Human cells, yeast, Bacteria etc.

ANSWER

Teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. Free ends of the wire are connected to a cell through a switch as shown in the Figure 14.3. The current is switched on and some pins are placed near the ends of the nail. What is the effect of current you observe in the above activity? Will the nail attract the safety pin kept near it? What is the iron nail made of soft iron called when wire is wounded around it and current is passed through it?

Posted by Sreenu Panchakatla 5 years, 2 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

What is silk with example

Posted by *Shrishti* Student Fast 5 years, 2 months ago

CBSE > Class 07 > Science

5 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer ... " Silk is a soft thread-like fiber spun by silkworms. Silk fibres are animal fibres obtained from cocoons of the silkworm. The rearing of silkworms for obtaining silk is called sericulture. It is a very old occupation in India. "

Pranathi Garimella 5 years, 2 months ago

Silk is a type of thread.

Prathmesh Charode 5 years, 2 months ago

Jshdh

Gaurav Seth 5 years, 2 months ago

Silk is a soft thread-like fiber spun by silkworms.

Silk fibres are animal fibres obtained from cocoons of the silkworm. The rearing of silkworms for obtaining silk is called sericulture. It is a very old occupation in India.

reeling the silk:
When the cocoons are kept under the sun or boiled or exposed to steam, the silk fibres separate out. The process of taking out threads from the cocoons for use as silk is called reeling the silk. It is done in special machines, which unwind the thread or fibres of silk from the cocoon.

.

Xxx Xxx 5 years, 2 months ago

Silk is a type of thread

ANSWER

Autotrophic meaning

Posted by Guglavath Vijaypal 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer..... " Auto means self and trophic means nourishment The organisms which synthesis own food are called autotrophic nutrition. "

*Shrishti* Student Fast 5 years, 2 months ago

Auto means self and trophic means nourishment The organisms which synthesis own food are called autotrophic nutrition

Vaishanavi Singh 5 years, 2 months ago

Autotrophic are any organism that are capable to produce their own food.

ANSWER

Q5-A spaceship travels 36,000 km in one hour. Express its speed in km/hr.

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

4 answers

Aradhya Jangid 5 years, 2 months ago

?28?

Khusi Yadav 5 years, 2 months ago

What are amoeba

Bhavika Mishra 5 years, 2 months ago

I cannot understand not now also

Sabu Kuriakose 5 years, 2 months ago

36, 000/60×60 36,000/3600 360/36 10 km/sec

ANSWER

What is the process of crystallisation

Posted by Himanshi Maitra 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Vinayak Singh 5 years, 2 months ago

The process of deriving large crystals of pure substances from their solutions is known as crystallisation. It is a physical change. Crystals of salt are obtained by the evaporation of sea water. Similarly crystals of copper sulphate can be obtained by adding copper sulphate powder to the boiling solution of water and dilute sulphuric acid. This mixture when filtered and allowed to cool produces crystals of copper sulphate.

ANSWER

What is ridiation

Posted by Murari Parsad 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer.... " The process of getting heat in the form of radiation is called radiation. For example, we are getting heat from the Sun in the form of radiation. "

Neelu Yadav 5 years, 2 months ago

All hot bodies emit heat by the process of radiation. Radiation of heat does not require a medium. Sunlight comes to the earth because of radiation as there is no medium present between the atmosphere of the earth and the sun. One can feel the heat of bonfire by standing around it. We get warmth from the room heater because of radiation.

Yogita Ingle 5 years, 2 months ago

All hot bodies emit heat by the process of radiation. Radiation of heat does not require a medium. Sunlight comes to the earth because of radiation as there is no medium present between the atmosphere of the earth and the sun.

One can feel the heat of bonfire by standing around it. We get warmth from the room heater because of radiation.

ANSWER

What is ridation

Posted by Murari Parsad 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Vidushi Malik 5 years, 2 months ago

Hey, here's your answer.... " The process of getting heat in the form of radiation is called radiation. For example, we are getting heat from the Sun in the form of radiation. "

Neelu Yadav 5 years, 2 months ago

All hot bodies emit heat by the process of radiation. Radiation of heat does not require a medium. Sunlight comes to the earth because of radiation as there is no medium present between the atmosphere of the earth and the sun. One can feel the heat of bonfire by standing around it. We get warmth from the room heater because of radiation.

Yogita Ingle 5 years, 2 months ago

All hot bodies emit heat by the process of radiation. Radiation of heat does not require a medium. Sunlight comes to the earth because of radiation as there is no medium present between the atmosphere of the earth and the sun.

One can feel the heat of bonfire by standing around it. We get warmth from the room heater because of radiation.

ANSWER

Use of Electromagnets??

Posted by Karthik Shibin 5 years, 2 months ago

CBSE > Class 07 > Science

2 answers

Murari Parsad 5 years, 2 months ago

What is magnet

Yogita Ingle 5 years, 2 months ago

Some electromagnet uses are given in the points mentioned below:

Particle Accelerators
Amplifiers
Magnetic Separation
Electric Motors and Generators
MRI machines
Control Switches in Relays
Transportation
Spacecraft Propulsion Systems
Induction Heating
Hard Drives

ANSWER

Q8- Which of these explains the formation of a rainbow? (a) Converging of light at a single point (b) Splitting of white light into different colours (c) Changing the direction of light by a polished surface (d) Mixing of various colours of light into a single colour

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

3 answers

Anjali Jindal 5 years, 2 months ago

b part Splitting of light into different colours

Asmi Sethi 5 years, 2 months ago

Yes Anushka I am your classmate only

Anushka Kapoor 5 years, 2 months ago

Are you from queens valley scho

ANSWER

How to take out the average speed ?

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

Yogita Ingle 5 years, 2 months ago

The average speed of a body in a certain time interval is the distance covered by the body in that time interval divided by time. So if a particle covers a certain distance s in a time t1 to t2, then the average speed of the body is:

v_av= s/ t₂–t₁

In general, average speed formula is:

Average Speed = Total Distance / Total Time

Now let us look at some of the examples to understand this concept easily

ANSWER

Q7-Which of these matches the nature of the image formed by the lens when an object is placed close to it? (a) Concave lens real and erect (b) Convex lens  real and larger (c) Convex lenslarge and inverted (d) Concave lens virtual and smaller

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

Q6- Which of these explains the reason why the virtual image can never be obtained on the screen? (a) They are too small to be obtained on a screen (b)The rays of light never converge after reflection (c)They always produce an erect image which is difficult to project (d)The rays of light are too bright and might burn the screen on projection

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

Q4- A car covers a total of 200 kilometres in 4 hours. What is the average speed of the car? (a)40 km/hr (b)50 km/hr (c)100 km/hr (d)800 km/hr

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

1 answers

S Balamani Kanta Reddy 8A 5 years, 2 months ago

Option b:- 50 km/hr

ANSWER

During a race, a cyclist covers a total of 30 km distance in an hour. What is the average speed of the cyclist? (a)10 km/hr (b)20 km/hr (c)30 km/hr (d)300 km/hr

Posted by Asmi Sethi 5 years, 2 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

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