Water from cucumber come out and size shrinks because it has smaller amount of salt thanthe solution outside . so water comes out to maintain balance
Tuesday, 26 April 2016
Juhi roll 7
Cell has less salt than the solution outside . so , to maintain the balance , water comes out
Anisha
Water from cucumber comes out because the cell inside the cucumber has lesser saltthan the solution outside . so , water comes out to maintain the balance
Ayush sharma roll no 25
Tuesday, 26 April 2016
CHAPTER = FUNDAMENTAL UNIT OF LIFE
Q. Why does the water come out from the cucumber when we add salt in it?
Ans, because of hypertonic and hypotonic conditions. The outside environment is hypertonic to the inside environment of the cucumber. Since there is less water outside or none and a high concentration of salt and there is a high concentration of water inside the cucumber and low salt or none at all. Through diffusion water will go from high to low concentration hence into to out. When water moves out its called osmosis
Amit chauhan
CHAPTER = FUNDAMENTAL UNIT OF LIFE
Q. Why does the water come out from the cucumber when we
add salt in it?
Ans Osmosis is the diffusion of a solvent
(frequently water) through a semi-permeable membrane, from a solution of low
solute concentration (high water potential) to a solution with high solute
concentration (low water potential), up a solute concentration gradient
The cells of the cucumber have low salt conent while the water around it has high salt content. Therefore, to get a balance, water is drawn out from the cucumber.
The cells of the cucumber have low salt conent while the water around it has high salt content. Therefore, to get a balance, water is drawn out from the cucumber.
Thursday, 21 April 2016
utkarsh shukla
EXERCISE(matter in our surrounding)
1. Convert the following temperature to Celsius scale:
(a) 300 K
= 300°C
1. Convert the following temperature to Celsius scale:
(a) 300 K
► 300 K = (300 - 273)°C
= 27°C
= 27°C
(b) 573 K
► 573 K = (573 - 273)°C= 300°C
2. Convert the following temperatures to Kelvin scale.
(a) 25°C
►25 °C = (25 + 273) K
= 298 K
(b) 373°C
► 373 °C = (373 + 273) K
= 646 K
(a) 25°C
►25 °C = (25 + 273) K
= 298 K
(b) 373°C
► 373 °C = (373 + 273) K
= 646 K
3. Give reason for the following observations.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
(a) Naphthalene balls disappear with time without leaving any solid because they undegoes sublimation easily i.e., the change of state of naphthalene from solid to gas takes place easily.
(b) Perfumes has high degree of vaporization and its vapour diffuse into air easily. Therefore, we can get the smell of perfume sitting several metres away.
(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.
(a) Naphthalene balls disappear with time without leaving any solid because they undegoes sublimation easily i.e., the change of state of naphthalene from solid to gas takes place easily.
(b) Perfumes has high degree of vaporization and its vapour diffuse into air easily. Therefore, we can get the smell of perfume sitting several metres away.
4. Arrange the following substances in increasing order of forces of attraction between particles-- water, sugar, oxygen.
Oxygen, Water, Sugar.
5. What is the physical state of water at-
(a) 25°C
► Liquid State
(b) 0°C
► Solid State, can also be in liquid state(conditions required).
(c) 100°C
► Gaseous State, can also be in liquid state(conditions required).
6. Give two reasons to justify-
(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.
(a) Water at room temperature is a liquid because it has fluidity also it has no shape but has a fixed volume that is, it occupies the shape of the container in which it is kept.
(b) An iron almirah is a solid at room temperature it has rigid and fixed shape.
7. Why is ice at 273 K more effective in cooling than water at the same temperature?
Ice at 273 K has less energy than water (although both are at the same temperature). Water possesses the additional latent heat of fusion. Hence, at 273 K, ice is more effective in cooling than water.
8. What produces more severe burns, boiling water or steam?
Steam has more energy than boiling water. It possesses the additional latent heat of vaporization. Therefore, burns produced by steam are more severe than those produced by boiling water.
9. Name A, B, C, D, E and F in the following diagram showing change in its state.
CHAPTER-2
THE FUNDAMENTAL UNIT LIFE
1). why water come out from cucumber when we pour salt ? The salt cause water to be drawn out of the cucumber. Water is drawn to it because it goes from a higher concentration of water to lower concentration. When there is random motion that will always happen and is called diffusion. Osmosis is a type of diffusion that involves a semipermeable membrane or a membrane like exists in the cells of cucumbers that allows water through but not the salt. That is why it is called semipermeable. Only some things gets through the membrane. When there is more salt dissolved in the water on one side of the membrane compared to the other there is less water on that side. They call that hypertonic. Water will move from the higher concentration hypotonic side to the lower concentration of water on the hypertonic side. That is how you should think of it. It will often be exosmosispress as more salt but you should think of it as more salt dissolved actually means less water. Water will diffuse from higher concentration of water (lower salt) to lower concentration (higher salt). Think of it like this. If you had 50 people in a single room and 20 in the other during a party and they were all moving around randomly. After an hour there will be fewer people in the crowded room if they move around randomly. That is why diffusion goes from higher concentration to lower. Just don't be confused when they say higher concentration of salt. High salt means less water. The water molecules are what moves around and when it involves a semipermeable membrane like in most living cells it is called
(a) 25°C
► Liquid State
(b) 0°C
► Solid State, can also be in liquid state(conditions required).
(c) 100°C
► Gaseous State, can also be in liquid state(conditions required).
6. Give two reasons to justify-
(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.
(a) Water at room temperature is a liquid because it has fluidity also it has no shape but has a fixed volume that is, it occupies the shape of the container in which it is kept.
(b) An iron almirah is a solid at room temperature it has rigid and fixed shape.
7. Why is ice at 273 K more effective in cooling than water at the same temperature?
Ice at 273 K has less energy than water (although both are at the same temperature). Water possesses the additional latent heat of fusion. Hence, at 273 K, ice is more effective in cooling than water.
8. What produces more severe burns, boiling water or steam?
Steam has more energy than boiling water. It possesses the additional latent heat of vaporization. Therefore, burns produced by steam are more severe than those produced by boiling water.
9. Name A, B, C, D, E and F in the following diagram showing change in its state.
CHAPTER-2
THE FUNDAMENTAL UNIT LIFE
1). why water come out from cucumber when we pour salt ? The salt cause water to be drawn out of the cucumber. Water is drawn to it because it goes from a higher concentration of water to lower concentration. When there is random motion that will always happen and is called diffusion. Osmosis is a type of diffusion that involves a semipermeable membrane or a membrane like exists in the cells of cucumbers that allows water through but not the salt. That is why it is called semipermeable. Only some things gets through the membrane. When there is more salt dissolved in the water on one side of the membrane compared to the other there is less water on that side. They call that hypertonic. Water will move from the higher concentration hypotonic side to the lower concentration of water on the hypertonic side. That is how you should think of it. It will often be exosmosispress as more salt but you should think of it as more salt dissolved actually means less water. Water will diffuse from higher concentration of water (lower salt) to lower concentration (higher salt). Think of it like this. If you had 50 people in a single room and 20 in the other during a party and they were all moving around randomly. After an hour there will be fewer people in the crowded room if they move around randomly. That is why diffusion goes from higher concentration to lower. Just don't be confused when they say higher concentration of salt. High salt means less water. The water molecules are what moves around and when it involves a semipermeable membrane like in most living cells it is called
Wednesday, 20 April 2016
SHRESTH GAUTAM 9 A
Chapter1 :- matter in our surroundins
*WHY DIVER IS ABLE TO CUT WATER?
ANS: The space is maximum in gasses and minimum in liquid, thus one cannot cut through a solid easily but a diver is able to cut water.
*WHY SMELL OF HOT SIZZLING FOOD REACHES IN OUR NOSE?
ANS: Particles of matter are continuously moving. They posses the kinitic energy. As the temperature rises particles move faster. Thus the particles can carry smell of hot sizzling food in our nose.
DATE :8-4-2016
*WHY DIVER IS ABLE TO CUT WATER?
ANS: The space is maximum in gasses and minimum in liquid, thus one cannot cut through a solid easily but a diver is able to cut water.
*WHY SMELL OF HOT SIZZLING FOOD REACHES IN OUR NOSE?
ANS: Particles of matter are continuously moving. They posses the kinitic energy. As the temperature rises particles move faster. Thus the particles can carry smell of hot sizzling food in our nose.
DATE :8-4-2016
Monday, 18 April 2016
SHASHANK ROLL.NO=44
Q-NAPTHALENE BALLS DISAPPEAR WITH TIME WITHOUT LEAVING ANY SOLID?
ans-because napthalene balls sublime and directly change into vapour state without leaving any solid
we can get the smell of perfumesitting several meters away?
ANS-because in perfume they contaion voltile solvent and diffused faster and can reach seveeal meter away
Q- Arrange the following substances in increasing order of force of attracting between the particles water,suger,oxygen.
Ans oxygen,water and suger.
Q what is trhe physical state of water at-
Ans (a) 25c is liquid
(b) 0c is solid or liquid.
(c) 100c is liquid and vapour.
Q Give reason
(a) water at room temperature is a liquid.
(b) An iron almirah is a solid at room temperature.
Ans (a) water at room temperature is a liquid beacuse its freezing point is 0c and boiling point is 100c.
(b) An iron almirah is a solid at room temperature because melting point of iron isa higher than room temperature
Q Why is ice at 273 k more effective in cooling than water at the same temperature ?
Ans Ice at 273 k Will take latent heat from the medium to overcome the fusion and then after gaining some more heat, it will become water, hence the cooling effect of ice is more than the water at same temperature because water does not take this extra heat from the medium .
Q What produces more serve burns, boiling water or steam?
Ans Steam at 100c will produce more servere burns as it has extra heat hidden in it called latent heat whereas the boiling water does not have this hidden heat.
Ans oxygen,water and suger.
Q what is trhe physical state of water at-
Ans (a) 25c is liquid
(b) 0c is solid or liquid.
(c) 100c is liquid and vapour.
Q Give reason
(a) water at room temperature is a liquid.
(b) An iron almirah is a solid at room temperature.
Ans (a) water at room temperature is a liquid beacuse its freezing point is 0c and boiling point is 100c.
(b) An iron almirah is a solid at room temperature because melting point of iron isa higher than room temperature
Q Why is ice at 273 k more effective in cooling than water at the same temperature ?
Ans Ice at 273 k Will take latent heat from the medium to overcome the fusion and then after gaining some more heat, it will become water, hence the cooling effect of ice is more than the water at same temperature because water does not take this extra heat from the medium .
Q What produces more serve burns, boiling water or steam?
Ans Steam at 100c will produce more servere burns as it has extra heat hidden in it called latent heat whereas the boiling water does not have this hidden heat.
karan bisht (30)
GIVE REASON
Q-NAPTHALENE BALLS DISAPPEAR WITH TIME WITHOUT LEAVING ANY SOLID?
ans-because napthalene balls sublime and directly change into vapour state without leaving any solid
we can get the smell of perfumesitting several meters away?
ANS-because in perfume they contaion voltile solvent and diffused faster and can reach seveeal meter away
Q- Arrange the following substances in increasing order of force of attracting between the particles water,suger,oxygen.
Ans oxygen,water and suger.
Q what is trhe physical state of water at-
Ans (a) 25c is liquid
(b) 0c is solid or liquid.
(c) 100c is liquid and vapour.
Q Give reason
(a) water at room temperature is a liquid.
(b) An iron almirah is a solid at room temperature.
Ans (a) water at room temperature is a liquid beacuse its freezing point is 0c and boiling point is 100c.
(b) An iron almirah is a solid at room temperature because melting point of iron isa higher than room temperature
Q Why is ice at 273 k more effective in cooling than water at the same temperature ?
Ans Ice at 273 k Will take latent heat from the medium to overcome the fusion and then after gaining some more heat, it will become water, hence the cooling effect of ice is more than the water at same temperature because water does not take this extra heat from the medium .
Q What produces more serve burns, boiling water or steam?
Ans Steam at 100c will produce more servere burns as it has extra heat hidden in it called latent heat whereas the boiling water does not have this hidden heat.
Ans oxygen,water and suger.
Q what is trhe physical state of water at-
Ans (a) 25c is liquid
(b) 0c is solid or liquid.
(c) 100c is liquid and vapour.
Q Give reason
(a) water at room temperature is a liquid.
(b) An iron almirah is a solid at room temperature.
Ans (a) water at room temperature is a liquid beacuse its freezing point is 0c and boiling point is 100c.
(b) An iron almirah is a solid at room temperature because melting point of iron isa higher than room temperature
Q Why is ice at 273 k more effective in cooling than water at the same temperature ?
Ans Ice at 273 k Will take latent heat from the medium to overcome the fusion and then after gaining some more heat, it will become water, hence the cooling effect of ice is more than the water at same temperature because water does not take this extra heat from the medium .
Q What produces more serve burns, boiling water or steam?
Ans Steam at 100c will produce more servere burns as it has extra heat hidden in it called latent heat whereas the boiling water does not have this hidden heat.
Friday, 15 April 2016
abhishek.singh Roll.no.-21
THIS IS MY HOMEWORK PAGE .
I WILL DO MY HOMEWORK PAGE
Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. We talk about the difference between mass and weight in another section. Matter is sometimes related to light and electromagnetic radiation. Even though matter can be found all over the Universe, you will only find it in a few forms on Earth. We cover five states of matter on the site. Each of those states is sometimes called a phase. There are many other states of matter that exist in extreme environments. Scientists will probably discover more states as we continue to explore the Universe.
Five States of Matter
GIVE REASONS
Q1-WHY TABLE IS HARD
Ans
TABLE IS HARD BECAUSE the molecule in the table are paked to gether.
It has fixed shape & fixed volume .So,the is hard .it can be cut with a scissor
Q2- Diver is able to cut water
Ans
The moleucules are lossely paked
Tere is intermolecular space.Take the shape of container & fixed volume.
Q3-The smell of hot sizzleing food reacher our nose
Ans
There might be several reasons for this.
Two possible explanations I can think of:
1) Particles at high temperatures carry a lot of energy. Because of this, they move about a lot more than cold particles. To say it another way, the kinetic energy (and thus their velocity) is a lot higher than that of colder particles, and so they are more mobile.
The particles that make up the food (in particular the molecules that trigger our sense of smell) also get more mobile if the food gets hotter, and therefor, they are able to reach us from a greater distance.
2) Food often contains large quantities of water. When food is cooked, this water evaporates and the water vapor is able to carry the food molecules over a great distance. Try to visualize it as tiny droplets of water containing the food's smell molecules and carrying them from the food to your nose.
Two possible explanations I can think of:
1) Particles at high temperatures carry a lot of energy. Because of this, they move about a lot more than cold particles. To say it another way, the kinetic energy (and thus their velocity) is a lot higher than that of colder particles, and so they are more mobile.
The particles that make up the food (in particular the molecules that trigger our sense of smell) also get more mobile if the food gets hotter, and therefor, they are able to reach us from a greater distance.
2) Food often contains large quantities of water. When food is cooked, this water evaporates and the water vapor is able to carry the food molecules over a great distance. Try to visualize it as tiny droplets of water containing the food's smell molecules and carrying them from the food to your nose.
Latent heat of fusion
the heat absorbed by a unit mass of a given solid at its melting point that completely converts the solid to a liquid at the same temperature: equal to the heat of solidification. Compare latent heat. heat of fusion in Science Expand.
Latent heat of soild
Solid
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a gas does. The atoms in a solid are tightly bound to each other, either in a regular geometric lattice (crystalline solids, which include metals and ordinary ice) or irregularly (an amorphous solid such as common window glass).
The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics(which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids.Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identification andchemical composition.
Evaporation
Evaporation is a type of vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase that is not saturated with the evaporating substance. The other type of vaporization is boiling, which is characterized by bubbles of saturated vapor forming in the liquid phase. Steam produced in a boiler is another example of evaporation occurring in a saturated vapor phase. Evaporation that occurs directly from the solid phase below the melting point, as commonly observed with ice at or below freezing or moth crystals (napthalene orparadichlorobenzene), is called sublimation.
----------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------------------------
Factors affecting the rate of evaporation
Factors affecting the rate of evaporation Mouseover the pictures to learn more
Subscribe to:
Posts (Atom)