Type of Hydrogen- Green Hydrogen Brown Hydrogen Grey Hydrogen Blue Hydrogen

Types of Hydrogen on the basis of production

Green Hydrogen

It is produced by electrolysis of water using renewable energy like wind, solar energy. India is front runner for production of green hydrogen.

Brown Hydrogen

It is hydrogen produced by using of coal. Emission gases are released in atmosphere.

Grey Hydrogen

It is hydrogen produced by using natural gas. Emission gases are released into atmosphere.

Blue Hydrogen

In this hydrogen is produced by using natural gas, and emission gases are absorbed and not to be released into atmosphere.

CLONING

 CLONING

Cloning is a technique scientist use to make exact genetic copies of living things. Genes, cells, tissues, and even whole animals can all be cloned.

Some clones already exist in nature. Single-celled organisms like bacteria make exact copies of themselves each time they reproduce. In humans, identical twins are similar to clones. They share almost the exact same genes. Identical twins are created when a fertilized egg splits in two.

Scientists also make clones in the lab. They often clone genes in order to study and better understand them. To clone a gene, researchers take DNA from a living creature and insert it into a carrier like bacteria or yeast. Every time that carrier reproduces, a new copy of the gene is made.

Animals are cloned in one of two ways. The first is called embryo twinning. Scientists first split an embryo in half. Those two halves are then placed in a mother’s uterus. Each part of the embryo develops into a unique animal, and the two animals share the same genes. The second method is called somatic cell nuclear transfer. Somatic cells are all the cells that make up an organism, but that are not sperm or egg cells. Sperm and egg cells contain only one set of chromosomes, and when they join during fertilization, the mother’s chromosomes merge with the father’s. Somatic cells, on the other hand, already contain two full sets of chromosomes. To make a clone, scientists transfer the DNA from an animal’s somatic cell into an egg cell that has had its nucleus and DNA removed. The egg develops into an embryo that contains the same genes as the cell donor. Then the embryo is implanted into an adult female’s uterus to grow.

In 1996, Scottish scientists cloned the first animal, a sheep they named Dolly. She was cloned using an udder cell taken from an adult sheep. Since then, scientists have cloned cows, cats, deer, horses, and rabbits. They still have not cloned a human, though. In part, this is because it is difficult to produce a viable clone. In each attempt, there can be genetic mistakes that prevent the clone from surviving. It took scientists 276 attempts to get Dolly right. There are also ethical concerns about cloning a human being.

Researchers can use clones in many ways. An embryo made by cloning can be turned into a stem cell factory. Stem cells are an early form of cells that can grow into many different types of cells and tissues. Scientists can turn them into nerve cells to fix a damaged spinal cord or insulin-making cells to treat diabetes.

The cloning of animals has been used in a number of different applications. Animals have been cloned to have gene mutations that help scientists study diseases that develop in the animals. Livestock like cows and pigs have been cloned to produce more milk or meat. Clones can even “resurrect” a beloved pet that has died. In 2001, a cat named CC was the first pet to be created through cloning. Cloning might one day bring back extinct species like the woolly mammoth or giant panda.

 Q1.1.Name the first mammal to be cloned from an adult cell.

(a)  Copy cat

(b)  Dolly

(c)  Snuppy

(d)  None of these

Q1.2. What is Cloning?

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Q1.3. Write two applications of animal cloning.

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Q1.3. Do you think that cloning is good practice? Justify.

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Catalytic Converter- PISA Competency Based Question in Chemistry

 

                            PISA Competency Based Question in Chemistry

Catalytic Converter

Most modern cares are fitted with a catalytic converter that makes the exhaust fumes of the car less harmful to people and to the environment.

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About 90% of harmful gases are converted into less harmful ones. Here are some of the gases that go into the converter and how they come out of it.

Catalytic Converter

Question 1 : Catalytic Converter

Use the information in the diagram above to give an example of how the catalytic converter makes exhaust fumes less harmful.

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CATALYTIC CONVERTER SCORING 1

Full credit

·       The conversion of carbon monoxide or nitrogen oxides, to other compound is mentioned.

·       Carbon Monoxide is changed into carbon dioxide.

·       Nitrogen oxides are changed into nitrogen.

·       It changes harmful fumes into non-harmful fumes. E.g. CO into CO2 (90%).

·       Carbon dioxide and nitrogen are not as harmful as carbon monoxide and nitrogen oxides.

No credit

·       Other responses.

·       The gases become less harmful.

·       It purifies the carbon monoxide and nitrogen oxides.

PLASTICS- PISA Competency Based Question in Chemistry

 

PLASTICS

The advent of fuel-based plastics has revolutionized the industrial world and there is no area of manufacturing which is untouched by plastics. Convenience and cost factors have pitch forked plastics as the most preferred material of choice till recently, a rethinking about its impact on environment and sustainability is slowly putting a brake on its continued use. While cheap petroleum fuels from which most plastics are derived was once justified to introduce them in place of traditional materials like glass and metals, this plea cannot hold any more since the cost of non-renewable fossil fuels increased several folds during the last 3 decades. 

Research based on plastics proves their injurious nature towards human health in many direct or indirect ways. Phthalates or phthalate esters are esters of phthalic acid mainly used as plasticizers (substances added to plastics to increase their flexibility) in Poly Vinyl Chloride (PVC). PVC is a widely used material, including extensive use in toys and other children's products such as chewy teethers, soft figures and inflatable toys. Di (2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), di-isononylphthalate (DINP), di-isodecyl phthalate (DIDP), benzyl - butyl - phthalate (BBP) and di-n- octyl- phthalate (DNOP) are phthalates mainly used in converting polyvinyl chloride (PVC) from a hard plastic to a flexible plastic. Phthalates migrate into the air, into food and into people including babies in their mother's wombs. Phthalates can be released from soft PVC by surface contact, especially where mechanical pressure is applied e.g., during chewing of a PVC teether). Release of phthalates during manufacture, use and disposal of PVC products, in addition to their use as additives in ink, perfumes etc. has lead to their ubiquitous distribution and abundance in the global environment.[1]

Growing literature links many of the phthalates with a variety of adverse outcomes, including increased adiposity and insulin resistance,[2] decreased anogenital distance in male infants,[3] decreased levels of sex hormones,[4] and other consequences for the human reproductive system, both for females and males,[5] Infants and children may be especially vulnerable to the toxic effects of phthalates given their increased dosage per unit body surface area, immature metabolic system capability and developing endocrine and reproductive system.

Question 1.1

 

Mention two reasons of popularity of plastics.

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Question intent:

Context: Science and Technology

Situation: Global

Process: Identifying plastics

Theme: Ill effects of plastic 

Level: Medium

Question format: short constructed response

 

Full credit: mentioning two reasons

Partial credit: mentioning one reason

No credit: For no reason or wrong answer

 

Question 1.2 

 

Plasticizers are used to -

1. make plastic strong
2. make plastic flexible
3. make plastic durable
4. make plastics colour

 

Question intent:

Context: Science and Technology

Situation: Global

Process: Demonstrating knowledge and understanding plastic

Theme: plastic 

Level: Medium

Question format: MCQ type.

 

Full credit: B. make plastic flexible

No credit: For other responses or missing

Question 1.3

Plastic has ill effects specially in human

A. Respiratory system

B. Circulatory system

C. Reproductive system

D. Excretory system

Question intent:

Context: Science and Technology

Situation: Global

Process: Demonstrating knowledge and understanding plastic

Theme: plastic 

Level: Medium

Question format: MCQ type.

 

Full credit: C Reproductive system

No credit: For other responses or missing

 

Question 1.4

Name two phthalates used to make PVC flexible.

 

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Question intent:

Context: Science and Technology

Situation: Global

Process:  understanding plastics

Theme: Ill effects of plastic 

Level: Medium

Question format: short response

 

Full credit: mentioning two

Partial credit: mentioning one

 No credit: for no answer or wrong answer 

Question 1.5

Phthalates migrate into –--------, ----------– and in human body to make its distribution global.

Question intent:

Context: Science and Technology

Situation: Global

Process:  understanding plastics

Theme: Ill effects of plastic 

Level: Medium

Question format: fill in the blanks

Full credit: mentioning two (air, food)

Partial credit: mentioning one (air or food)

No credit: for no answer or wrong answer