Acetic acid is a colourless liquid. Its is miscribe/soluble in water(or any other physical property). On adding a pinch of sodium hydrogen carbonate, Brisk effervescence is observed. Evolution of a colourless/odourless gas.
Acetic acid is a colourless liquid.
Its is miscribe/soluble in water(or any other physical property).
On adding a pinch of sodium hydrogen carbonate,
Brisk effervescence is observed.
Evolution of a colourless/odourless gas.
Speciation- Formation of new species from pre-existing ones. Factors- 1. Mutations 2. Natural selection 3. Genetic drift 4. Geographical isolation Geographical isolation cannot be a major factor in the speciation of a self-pollinating plant species Reason: Physical barrier cannot be created in self-Read more
Speciation- Formation of new species from pre-existing ones.
Factors-
1. Mutations
2. Natural selection
3. Genetic drift
4. Geographical isolation
Geographical isolation cannot be a major factor in the speciation of a self-pollinating plant species
Reason: Physical barrier cannot be created in self-pollinating plants.
Carbon has 4 electrons in its outermost shell. It cannot lose 4 electrons to form c4+ because very high energy is required to remove 4 electrons. It cannot gain 4 electrons to form c4- ions because it is difficult for 6 protons to hold on to 10 electrons. Ionic/ Electrovalent bonds. Covalent bonds TRead more
Carbon has 4 electrons in its outermost shell. It cannot lose 4 electrons to form c4+ because very high energy is required to remove 4 electrons.
It cannot gain 4 electrons to form c4- ions because it is difficult for 6 protons to hold on to 10 electrons.
Ionic/ Electrovalent bonds.
Covalent bonds
There are no charged particles in carbon compounds and hence poor conductor of electricity.
(a) In a food chain the energy moves progressively through the various tropic levels and is no longer available to the organisms of the previous trophic level/ energy captured by the autotrophs does not revert back to the solar input. (b) Pesticides used for crop protection when washed away/ down inRead more
(a) In a food chain the energy moves progressively through the various tropic levels and is no longer available to the organisms of the previous trophic level/ energy captured by the autotrophs does not revert back to the solar input.
(b) Pesticides used for crop protection when washed away/ down into the soil/ water bodies absorbed by plants/ producers.
(c) On consumption they enter our food chain and being non-biodegradable these chemicals get accumulated progressively and enter our body.
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently. Example: Forelimbs of frog and bird. (ii) Analogous organs. Analogous organs are structurally and developmentaRead more
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently.
Example: Forelimbs of frog and bird.
(ii) Analogous organs. Analogous organs are structurally and developmentally quite different from each other i.e., they have different origins.
But they performs similar functions in different animals.
Example: The wings of a bird and wings of a bat.
(iii) Fossils. The remains or impressions of dead and decayed plants and animals are called fossils. Fossils tell us how new species are developed from the old one.
Example: Fossils of dinosaurs.
Three advantages of vegetative propagation: (i) Plants which do not produce viable seeds can be propagated by this method. (ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds. (iii) Superior quality of plants can be obtained.
Three advantages of vegetative propagation:
(i) Plants which do not produce viable seeds can be propagated by this method.
(ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds.
(iii) Superior quality of plants can be obtained.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo's side and blood spaces on the mother side. Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo’s side and blood spaces on the mother side.
Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Elements P,Q R and S are the elements of third period, these must have three filled shells. Electronic configuration of R: 2,8,5 Valency of R: 8-5 = 3 Electronic configuration of P: 2,8,1 Electronic configuration of S: 2,8,7 :Formula of the compound formed by the combination of P and S: PS/NaCI.
Elements P,Q R and S are the elements of third period, these must have three filled shells.
Electronic configuration of R: 2,8,5
Valency of R: 8-5 = 3
Electronic configuration of P: 2,8,1
Electronic configuration of S: 2,8,7
:Formula of the compound formed by the combination of P and S: PS/NaCI.
Advantages of conserving water in the form of ground water: (i) It does not evaporate. (ii) Spreads out to recharge wells. (iii) Provides moisture for vegetation over a large area. (iv) Does not provide breeding ground for mosquitoes. (v) Remain protected from contamination from human excreta, etc.
Advantages of conserving water in the form of ground water:
(i) It does not evaporate.
(ii) Spreads out to recharge wells.
(iii) Provides moisture for vegetation over a large area.
(iv) Does not provide breeding ground for mosquitoes.
(v) Remain protected from contamination from human excreta, etc.
A student is studying the properties of acetic acid. List two physical properties of acetic acid he observes. What happens when he adds a pinch of sodium hydrogen carbonate to this acid? Write any two observations.
Acetic acid is a colourless liquid. Its is miscribe/soluble in water(or any other physical property). On adding a pinch of sodium hydrogen carbonate, Brisk effervescence is observed. Evolution of a colourless/odourless gas.
Acetic acid is a colourless liquid.
See lessIts is miscribe/soluble in water(or any other physical property).
On adding a pinch of sodium hydrogen carbonate,
Brisk effervescence is observed.
Evolution of a colourless/odourless gas.
A student puts a drop of a solution of caustic soda first on a blue litmus paper and then on a red litmus paper. He would observe that
The red litmus paper turns blue and there is no change in the blue litmus paper.
The red litmus paper turns blue and there is no change in the blue litmus paper.
See lessWhat is speciation? List four factors that could lead to speciation. Which of the cannot be a major factor in the speciation of a self- pollinating plant species? Explain briefly.
Speciation- Formation of new species from pre-existing ones. Factors- 1. Mutations 2. Natural selection 3. Genetic drift 4. Geographical isolation Geographical isolation cannot be a major factor in the speciation of a self-pollinating plant species Reason: Physical barrier cannot be created in self-Read more
Speciation- Formation of new species from pre-existing ones.
See lessFactors-
1. Mutations
2. Natural selection
3. Genetic drift
4. Geographical isolation
Geographical isolation cannot be a major factor in the speciation of a self-pollinating plant species
Reason: Physical barrier cannot be created in self-pollinating plants.
Elements forming ionic compounds attain noble gas electronic configuration by either gaining or losing electrons from their valence shells. Explain giving reason why carbon cannot attains such a configuration in this manner to from its compounds. Name the type of bonds formed in ionic compounds and in the compound formed by carbon. also explain with reason why carbon compounds are generally poor conductors of electricity.
Carbon has 4 electrons in its outermost shell. It cannot lose 4 electrons to form c4+ because very high energy is required to remove 4 electrons. It cannot gain 4 electrons to form c4- ions because it is difficult for 6 protons to hold on to 10 electrons. Ionic/ Electrovalent bonds. Covalent bonds TRead more
Carbon has 4 electrons in its outermost shell. It cannot lose 4 electrons to form c4+ because very high energy is required to remove 4 electrons.
See lessIt cannot gain 4 electrons to form c4- ions because it is difficult for 6 protons to hold on to 10 electrons.
Ionic/ Electrovalent bonds.
Covalent bonds
There are no charged particles in carbon compounds and hence poor conductor of electricity.
” Energy Flow in food chains is always unidirectional.” justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.
(a) In a food chain the energy moves progressively through the various tropic levels and is no longer available to the organisms of the previous trophic level/ energy captured by the autotrophs does not revert back to the solar input. (b) Pesticides used for crop protection when washed away/ down inRead more
(a) In a food chain the energy moves progressively through the various tropic levels and is no longer available to the organisms of the previous trophic level/ energy captured by the autotrophs does not revert back to the solar input.
See less(b) Pesticides used for crop protection when washed away/ down into the soil/ water bodies absorbed by plants/ producers.
(c) On consumption they enter our food chain and being non-biodegradable these chemicals get accumulated progressively and enter our body.
Describe any three methods of tracing evolutionary relationship among arganisms.
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently. Example: Forelimbs of frog and bird. (ii) Analogous organs. Analogous organs are structurally and developmentaRead more
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently.
See lessExample: Forelimbs of frog and bird.
(ii) Analogous organs. Analogous organs are structurally and developmentally quite different from each other i.e., they have different origins.
But they performs similar functions in different animals.
Example: The wings of a bird and wings of a bat.
(iii) Fossils. The remains or impressions of dead and decayed plants and animals are called fossils. Fossils tell us how new species are developed from the old one.
Example: Fossils of dinosaurs.
List Three advantages of vegetative propagation.
Three advantages of vegetative propagation: (i) Plants which do not produce viable seeds can be propagated by this method. (ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds. (iii) Superior quality of plants can be obtained.
Three advantages of vegetative propagation:
See less(i) Plants which do not produce viable seeds can be propagated by this method.
(ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds.
(iii) Superior quality of plants can be obtained.
What is placenta? Explain its function in humans.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo's side and blood spaces on the mother side. Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo’s side and blood spaces on the mother side.
See lessFunction: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Four elements P,Q,R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valencies. Write the molecular formula of the compound formed when P and S combine.
Elements P,Q R and S are the elements of third period, these must have three filled shells. Electronic configuration of R: 2,8,5 Valency of R: 8-5 = 3 Electronic configuration of P: 2,8,1 Electronic configuration of S: 2,8,7 :Formula of the compound formed by the combination of P and S: PS/NaCI.
Elements P,Q R and S are the elements of third period, these must have three filled shells.
See lessElectronic configuration of R: 2,8,5
Valency of R: 8-5 = 3
Electronic configuration of P: 2,8,1
Electronic configuration of S: 2,8,7
:Formula of the compound formed by the combination of P and S: PS/NaCI.
List four advantages of conserving water in the form of ground water.
Advantages of conserving water in the form of ground water: (i) It does not evaporate. (ii) Spreads out to recharge wells. (iii) Provides moisture for vegetation over a large area. (iv) Does not provide breeding ground for mosquitoes. (v) Remain protected from contamination from human excreta, etc.
Advantages of conserving water in the form of ground water:
See less(i) It does not evaporate.
(ii) Spreads out to recharge wells.
(iii) Provides moisture for vegetation over a large area.
(iv) Does not provide breeding ground for mosquitoes.
(v) Remain protected from contamination from human excreta, etc.