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Chemical reaction that release energy in the form of heat, light and sound are called exothermic reaction.Reaction that observed energy or required energy in order to proceed is called endothermic reaction

Exothermic reaction :An exothermic reaction is a chemical reaction that releases energy in the form of light or heat.It gives net energy to its surroundings. That is, the energy needed to initiate the reaction is less than the energy that is subsequently released.

reactants → products + energyExamples of exothermic reactions:

Calcium oxide reacts vigorously with water to produce slaked lime(Calcium hydroxide) used in white washing releasing large amount of heat.

Burning of natural gas:when methane reacts with oxygen it releases vast amount of heat and cabon oxide and water.

2. Endothermic reaction :An endothermic reaction is any chemical reaction that absorbs heat from its environment.

reactants + energy → productsExample of endothermic reactions :

Melting of ice: Ice takes heat from the surroundings and turns in to liquid water.

Decomposition of Calcium Carbonate: When limestone is heated at above 900ºC it decomposes into quick lime and releases carbondioxide. CaCO3(limestone)-------------> CaO(quick lime) + CO2

Many chemical reactions release energy in the form of heat, light, or sound. These areexothermic reactions. Exothermic reactions may occur spontaneously and result in higher randomness orentropy(ΔS > 0) of the system. They are denoted by a negative heat flow (heat is lost to the surroundings) and decrease in enthalpy (ΔH < 0).

eg:

An example of an exothermic reaction is the mixture of sodium and chlorine to yield table salt. This reaction produces 411 kJ of energy for each mole of salt that is produced:

Na(s) + 0.5Cl2(s) = NaCl(s)

There are other chemical reactions that must absorb energy in order to proceed. These areendothermic reactions. Endothermic reactions cannot occur spontaneously. Work must be done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured during the reaction.

Endothermic reactions are characterized by positive heat flow (into the reaction) and an increase in enthalpy (+ΔH).

eg: Photosynthesis

sunlight + 6CO2(g) + H2O(l) = C6H12O6(aq) + 6O2(g)

exothermic reaction means- heat is evolved in that particular reaction where as endothermic reaction means - heat is absorbed in that particular reaction...

Anexothermicprocess releases heat, causing the temperature of the immediate surroundings to rise. An endothermicprocess absorbs heat and cools the surroundings.”

REACTION WHICH REQUIRES ENERGY EITHER IN THE FOR OF HEAT LIGHT AND ELECTRICITY IS KNOWN AS ENDOTHERMIC REACTION

REACTION WHICH RELEASES ENERGY IN THE FORM OF HEAT LIGHT IS KNOWN AS EXOTHERMIC REACTION

Distillationis a widelyusedmethod for separatingmixturesbased on differences in theconditionsrequired to change the phase of components of themixture. Toseparate a mixtureof liquids, the liquid can be heated to force components, which have different boiling points, into the gas phase.

Atomicity is the total number of atoms present in one molecule of an element, compound or a substance. For example, in O2, there are 2 atoms of oxygen.

Atomic number is the number of protons or electrons normally found in an atom of a given chemical element. The higher the atomic number, the heavier the atom is. In a neutral atom, the number of protons and electrons is the same.

Isotopes are atoms that have the same number of protons and electrons but different numbers of neutrons and therefore have different physical properties.

1.The kabadiwala is a scrap dealer. He is a true friend of nature as his profession is to trade generally with domestic non-biodegradable and useless wastes. The kabadiwala purchases these wastes from our house and further sell them to big traders for recycling which otherwise would not have been possible by an individual and might have stored as junk that will not perish with natures helps.

2.Yes, it isbetter to use compost instead of chemical fertilizersbecause byusing compost, we are reusing our garbage As,Compostis nature's way of recycling organic material back into the environment. ... Alsocompostis cheap and less harmful to thanchemical fertilizers.Compostfeeds the microfauna in the soil.

Some substances, like magnesium catches fireand burnswith a dazzling whiteflamewhen heated in air. Similarly, when a piece of per is brought near acandle flame, itburns, producing heatandlight. The charcoaland coalbums in air producing carbon dioxide, heatandlight.

2 and 3 question

An exothermic reaction is a chemical reaction that releases energy through light or heat. It is the opposite of an endothermic reaction

in exothermic reaction heat is evolved

Unlike many otherendothermic reactions,photosynthesisdoes not absorb energy as heat. Instead, during plants absorb energy from sunlight to turn carbon dioxide and water into oxygen and glucose, which is a type of sugar molecule. The energy is stored in the glucose molecules, ready to be used when needed.

Exothermic reaction.

Exothermic rxn

burning of natural gas is exothermic reaction

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Mg+2Hcl= mgcl2+ H2thanks

Mg+2HCl=Mgcl2+H2 answer of your questions

Wateris a betteracid than alcoholbecause of the electron donating nature of the alkyl group attached to the oxygen which destabilizes the hydroxide(in the case ofalcohol,Alkoxide) ion and makes it tougher for the oxygen to donate the proton.

option (d)

The combustion of methaneis an example of anexothermicreaction.

No alkanes are not soluble in water.Water is a polar solvent and has hydrogen bonding. For any compound to be soluble in water , it should be polar or have hydrogen bonding in it.Alkanes lack Polarity and Hydrogen bonding , so insoluble in water.

Effects of deforestation____Roots hold the soil and does not allow the process of soil erosion. As trees gets cut soil starts to move and get carried by water, air etc thus reducing the fertility if soil and water retaining capacity of the soil. Soil is no longer able to store the water within it and water gets evaporated by the heart of sun thus causing the process of desertification (For more__Desertification is the process in which land gets converted into desserts or marshy lands by human activities or Natural process.)

10q so much

a) water + chalk is the correct answe

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Bulb of a thermometer is always kept above the surface of water while determining the boiling point so as to make sure that the bulb doesn't breaks due to very high temperatureif the bulb is kept inside the boiling water it may break and the temperature cannot be taken

1) decomposition2) combination3) displacement4) displacement

option (d) is correct.

Graphite is more stable than diamond and energy is needed to convert graphite into diamond. The extra energy that has to be provided ends up in the tetrahedral structure of diamond.The energy content of diamond is slightly higher than that of graphite. Also the activation energy for this conversion is very high.

option (b) is also correct.

To decompose requires water to be split into H and O.

This is similar to decomposition of any other molecule, to break it apart, to make it no longer what it was before that.

Either way, to decompose water would be an endothermic reaction because you need to put a lot of energy into the system to break the H-O bond.

The system does not release any energy during this process (making it an endothermic reaction). To decompose water most effectively, electrolysis should be used.

Uses of Ethanol are as follows:1) Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic. 2) Ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores.3) The alcohol that we drink is simply ethanol.4) It is also used as a fuel. It burns in air to give carbon dioxide and water and can be used in combination with gasoline.

Uses of baking soda:1.Relieve insect bites2.Relieve heartburn3.Use as an Antacid4.Simple Air Freshener

Bond orderis the number of chemicalbondsbetween a pair of atoms.Forexample, in diatomic nitrogen N≡N the bond order is 3for O2 O=O bond order is 2

The central atom is sp² hybridized with one lone pair. Ozone is a polar molecule with a dipole moment of 0.53 D. The bonding can be expressed as a resonance hybrid with a single bond on one side and double bond on the other producing an overall bond order of1.5for each side.

Thank you very much

If the molecule is H2- , then there are ,3 electrons..

so, the last electron will move to the ABMO , above.. which has been shown vacant in the image below.

so, B.O = (2-1)/2 = 1/2.

It is a displacement reaction. Due to high reactive metal zinc displaced copperfrom its ion.

Thereactionofan acidwith a base iscalleda neutralizationreaction.

neutralization reaction take place salt and water are the product.Hence, option "a" is the right answer.

the reaction of an acid witha base results in formation of salts is called neutralization reaction . So "A" is the right answer.

Adecomposition reactionis a type of chemicalreactionwhere one reactant yields two or more products. The general form for adecomposition reactionis. AB → A + B.Decomposition reactionsare also known as analysisreactionsor a chemical breakdown.

Chemical decomposition, analysis or breakdown is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds. Chemical decomposition is usually regarded and defined as the exact opposite of chemical synthesis.

Bridging does not allow the other 2 variants to exist. Total no. of stereoisomers of M = 2

The chemical formula of ammonium ion is [NH4]+. Thevalencyis almost always +1 as it has one electron free on the central N atom.

Ans :- The slightest quirk creates acolored diamond: a bit of boron makes a blue diamond; nitrogen makes a yellow diamond; natural radiation form nearby rocks trap electrons to create a green surfacecolor; pink or red shadesarethought tobedue to changes to the electron structure during the voyage to the surface.

this ans has think by u or google it

as this is a first order reaction

75=50+25=30min

50+25+12.5=87.5=60min

50+25+12.5+6.25=93.75=120min

hence option b

Firstly find out rate of reaction K using,K=(2.303/60) * log (100/40)Now take this k, which come out to be 0.0152 per minute.

For finding time for 50%, you can use any of the 2 approach:

1) you can use the same formual above and substitute the value of k to find time, here log will have different values.

t= (2.303/0.0152)*log(100/50)t= 45.6 minutes.

2) you can use half life formula for first order reaction.

t=0.693/kt=0.693/0.0152t=45.6 minutes.

I hope this answers the question.

The latent heat of vaporisation is the heat energy required to change 1 kg of liquid to gas at atmospheric pressure at it's boiling point.whereasThe latent heat of fusion is the heat energy required to change 1 kg of solid to gas at atmospheric pressure at it's melting point.

latent heat of vaporisation is 1kg liquid change into gas and latent heat of fusion is 1kg of solid change into gas.

isotones have same no of neutrone- in Ge = 76-32 = 44 so, option i→ 77-33 = 44 , option iii→ 78-34 = 44 option A

Two common forms oflatent heatarelatent heatof fusion (melting) andlatent heatof vaporization (boiling). These names describethedirection of energy flow when changing from one phase tothenext: from solid to liquid, and liquid to gas.

Steps

Bayer process. The Bayer process is the principal industrial, means of refining bauxite to produce alumina (aluminium oxide). Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide