class 9: 2022

Friday, September 2, 2022

Class 9 MCQ

About the app

Class 9 MCQ is designed for the class 9 students to practice multiple choice questions. The app contain MCQ questions of each chapter of class 9 English, Hindi, Mathematics, Science and Social Science.

What's new

You will get new set time to time.

Monetization

To provide the free service and for the development of app we will show ads (provided by Google)

If you find any problem or want to give any suggestions, please mail us at digstudying@gmail.com

Privacy Policy for Class 9 MCQ

DIGITAL LEARNING built the Class 9 MCQ app as an Ad Supported app. This SERVICE is provided by DIGITAL LEARNING at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

If you choose to use my Service, then you agree to the collection and use of information in relation to this policy. The Personal Information that I collect is used for providing and improving the Service. I will not use or share your information with anyone except as described in this Privacy Policy.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Class 9 MCQ unless otherwise defined in this Privacy Policy.

Information Collection and Use

For a better experience, while using our Service, I may require you to provide us with certain personally identifiable information. The information that I request will be retained on your device and is not collected by me in any way.

The app does use third-party services that may collect information used to identify you.

Link to the privacy policy of third-party service providers used by the app

Log Data

I want to inform you that whenever you use my Service, in a case of an error in the app I collect data and information (through third-party products) on your phone called Log Data. This Log Data may include information such as your device Internet Protocol (“IP”) address, device name, operating system version, the configuration of the app when utilizing my Service, the time and date of your use of the Service, and other statistics.

Cookies are files with a small amount of data that are commonly used as anonymous unique identifiers. These are sent to your browser from the websites that you visit and are stored on your device's internal memory.

This Service does not use these “cookies” explicitly. However, the app may use third-party code and libraries that use “cookies” to collect information and improve their services. You have the option to either accept or refuse these cookies and know when a cookie is being sent to your device. If you choose to refuse our cookies, you may not be able to use some portions of this Service.

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;
To provide the Service on our behalf;
To perform Service-related services; or
To assist us in analyzing how our Service is used.

I want to inform users of this Service that these third parties have access to their Personal Information. The reason is to perform the tasks assigned to them on our behalf. However, they are obligated not to disclose or use the information for any other purpose.

Security

I value your trust in providing us your Personal Information, thus we are striving to use commercially acceptable means of protecting it. But remember that no method of transmission over the internet, or method of electronic storage is 100% secure and reliable, and I cannot guarantee its absolute security.

Links to Other Sites

This Service may contain links to other sites. If you click on a third-party link, you will be directed to that site. Note that these external sites are not operated by me. Therefore, I strongly advise you to review the Privacy Policy of these websites. I have no control over and assume no responsibility for the content, privacy policies, or practices of any third-party sites or services.

Children’s Privacy

These Services do not address anyone under the age of 13. I do not knowingly collect personally identifiable information from children under 13 years of age. In the case I discover that a child under 13 has provided me with personal information, I immediately delete this from our servers. If you are a parent or guardian and you are aware that your child has provided us with personal information, please contact me so that I will be able to do the necessary actions.

Changes to This Privacy Policy

I may update our Privacy Policy from time to time. Thus, you are advised to review this page periodically for any changes. I will notify you of any changes by posting the new Privacy Policy on this page.

This policy is effective as of 2022-09-02

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at digstudying@gmail.com.

Thursday, September 1, 2022

Privacy Policy for Class 8 MCQ

DIGITAL LEARNING built the Class 8 MCQ app as an Ad Supported app. This SERVICE is provided by DIGITAL LEARNING at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Class 8 MCQ unless otherwise defined in this Privacy Policy.

Information Collection and Use

The app does use third-party services that may collect information used to identify you.

Link to the privacy policy of third-party service providers used by the app

Log Data

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;
To provide the Service on our behalf;
To perform Service-related services; or
To assist us in analyzing how our Service is used.

Security

Links to Other Sites

Children’s Privacy

These Services do not address anyone under the age of 13.

Changes to This Privacy Policy

This policy is effective as of 2022-09-01

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at digstudying@gmail.com.

Monday, August 22, 2022

Privacy Policy for Social Science(SST) Ix MCQ

DIGITAL LEARNING built the Social Science(SST) Ix MCQ app as an Ad Supported app. This SERVICE is provided by DIGITAL LEARNING at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Social Science(SST) Ix MCQ unless otherwise defined in this Privacy Policy.

Information Collection and Use

The app does use third-party services that may collect information used to identify you.

Link to the privacy policy of third-party service providers used by the app

Log Data

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;
To provide the Service on our behalf;
To perform Service-related services; or
To assist us in analyzing how our Service is used.

Security

Links to Other Sites

Children’s Privacy

Changes to This Privacy Policy

This policy is effective as of 2022-08-22

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at digstudying@gmail.com.

Privacy policy for Science IX MCQ

DIGITAL LEARNING built the Science IX MCQ app as an Ad Supported app. This SERVICE is provided by DIGITAL LEARNING at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Science IX MCQ unless otherwise defined in this Privacy Policy.

Information Collection and Use

The app does use third-party services that may collect information used to identify you.

Link to the privacy policy of third-party service providers used by the app

Log Data

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;
To provide the Service on our behalf;
To perform Service-related services; or
To assist us in analyzing how our Service is used.

Security

Links to Other Sites

Children’s Privacy

Changes to This Privacy Policy

This policy is effective as of 2022-08-22

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at digstudying@gmail.com.

Privacy policy for Hindi Ix MCQ

DIGITAL LEARNING built the Hindi A IX MCQ app as an Ad Supported app. This SERVICE is provided by DIGITAL LEARNING at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decided to use my Service.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Hindi A IX MCQ unless otherwise defined in this Privacy Policy.

Information Collection and Use

The app does use third-party services that may collect information used to identify you.

Link to the privacy policy of third-party service providers used by the app

Log Data

Service Providers

I may employ third-party companies and individuals due to the following reasons:

To facilitate our Service;
To provide the Service on our behalf;
To perform Service-related services; or
To assist us in analyzing how our Service is used.

Security

Links to Other Sites

Children’s Privacy

Changes to This Privacy Policy

This policy is effective as of 2022-08-22

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at digstudying@gmail.com.

Wednesday, February 2, 2022

Atoms and Molecules NCERT Solutions

Question 1: A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

Answer: Percentage of boron in given compound $= (\frac{0.096}{0.24}) \times 100 = 40 %$
Percentage of oxygen in given compound $= (\frac{0.144}{0.24}) \times 100 = 60 %$

Question 2: When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?

Answer: We know that atoms of different elements combine in definite proportions to make a particular compound. Hence, 3 g of carbon will always give 11 g of carbon dioxide.

Question 3: What are polyatomic ions? Give examples.

Answer: An ion with more than one atom is called a polyatomic ion. Examples: Sulphate (SO42-), Nitrate (NO32-)

Question 4: Write the chemical formulae of the following.

(a) Magnesium chloride
(b) Calcium oxide
(c) Copper nitrate
(d) Aluminium chloride
(e) Calcium carbonate.

Answer: (a) MgCl2, (b) CaO, (c) CuNO3, (d) AlCl3, (e) CaCO3

Question 5: Give the names of the elements present in the following compounds.

(a) Quick lime
(b) Hydrogen bromide
(c) Baking powder
(d) Potassium sulphate.

Answer: (a) Calcium, oxygen, (b) Hydrogen, bromine, (c) sodium, hydrogen, carbon, oxygen, (d) Potassium, sulphur, oxygen

Question 6: Calculate the molar mass of the following substances.

(a) Ethyne, C2H2

Answer: $2 \times 12 + 2 \times 1 = 26$ u

(b) Sulphur molecule, S8

Answer: $8 \times 32 = 256$ u

Answer: $4 \times 31 = 124$

(d) Hydrochloric acid, HCl

Answer: $1 \times 1 + 1 \times 35.5 = 36.5$ u

(e) Nitric acid, HNO3

Answer: $1 \times 1 + 1 \times 14 + 3 \times 16 = 63$ u

Question 7: What is the mass of:

(a) 1 mole of nitrogen atoms?

Answer: Atomic mass of nitrogen = 14 u
Hence, mass of 1 mole of nitrogen atoms = 14 g

(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?

Answer: Atomic mass of aluminium = 27 u
Hence, mass of 4 moles of aluminium atoms $= 4 \times 27 = 108$

Answer: Molecular mass of sodium sulphite
$= 2 \times 23 + 1 \times 32 + 3 \times 16 = 46 + 32 + 48 = 126 u$
Hence, mass of 10 mole of sodium sulphite $= 10 \times 126 = 1260 g$

Question 8: Convert into mole.

(a) 12 g of oxygen gas

Answer: Mass of 1 mole of oxygen = 32 g
Hence, number of mole in 12 g oxygen $= \frac{12}{32} = 0.375 M$

(b) 20 g of water

Answer: Molecular mass of water $= 2 \times 1 + 1 \times 16 = 18 u$
So, mass of 1 mole of water = 18 g
Hence, number of mole in 20 g of water $= \frac{20}{18} = 1.11 M$

Answer: Molecular mass of carbon dioxide $= 1 \times 12 + 2 \times 16 = 44 u$
So, mass of 1 mole of carbon dioxide = 44 g
Hence, number of mole in 22 g of carbon dioxide $= \frac{22}{44} = 0.5 M$

Question 9: What is the mass of

(a) 0.2 mole of oxygen atoms?

Answer: Mass of 1 mole oxygen atoms = 16 g
Hence, mass of 0.2 mole of oxygen atoms $= 0.2 \times 16 = 3.2 g$

(b) 0.5 mole of water molecules?

Answer: Mass of 1 mole of water = 18 g
Hence, mass of 0.5 mole of water $= 0.5 \times 18 = 9 g$

Quesiton 10: Calculate the number of molecules of sulphur (S8) present in 16 g of solid sulphur.

Answer: Mass of 1 mole of sulphur $= 8 \times 32 = 256 g$
Hence, number of mole in 16 g of sulphur $= \frac{16}{256} = 0.625 M$

Question 11: Calculate the number of aluminium ions present in 0.051 g of aluminium oxide. (Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)

Answer: Formula of aluminium oxide = Al2O3
Mass of aluminium atoms in aluminium oxide $= 2 \times 27 = 54 u$
Molecular mass of aluminium oxide $= 2 \times 27 + 3 \times 16 = 54 + 48 = 102 u$

Here; 2 mole aluminium ions are present in 102 g aluminium oxide
Hence, number of aluminium ions in 0.051 g aluminium oxide
$= (\frac{2}{102}) \times 0.051 = \frac{2}{2000}$ mole
$= \frac{6.022 \times 10^{23}}{1000} = 6.022 \times 10^{20}$