Answer:
2835 J
Explanation:
Take the specific heat capacity of water as 4.2 J/ g°C.
Energy (heat) = mass x specific heat capacity x change in temperature
(E= mcΔT)
E = 27 x 4.2 x (45-20)
E = 2835 J
Answer:
The correct answer is option a.
Explanation:
Equilibrium concentration cadmium ions = ![[Cd^{2+}]=0.0585 M](https://tex.z-dn.net/?f=%5BCd%5E%7B2%2B%7D%5D%3D0.0585%20M)
Equilibrium concentration fluoride ions = ![[F^{-}]=0.117 M](https://tex.z-dn.net/?f=%5BF%5E%7B-%7D%5D%3D0.117%20M)
Molar solubility is the maximum concentration of salt present in water in ionic form beyond that no more salt will exist in its ionic form and will settle down in bottom of the solution.
The molar solubility of the solid cadmium fluoride = 0.0585 M
..[1]
Due to addition of sodium fluoride will increase concentration of fluoride in the solution.And due to common ion effect the equilibrium will shift in backward direction in [1], that is precipitation of more cadmium fluoride.
Hence, decrease in solubility will be observed.
Answer:
- <u>1. Since the temperature of your body is higher than the temperature of the air and of the water, heat will flow from your body to the air and pool.</u>
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- <u>2. The pool feels cooler than air because the water can absorb heat energy faster than the air, due to liquids are better conductors than gases.</u>
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Explanation:
Heat always flows from warmer substances to colder ones.
The normal body temperature is 98ºF. Therefore, the heat will flow from your body to the air and pool, which are at a lower temperature of 80ºF. In both cases, you will lose thermal energy and the external parts of your body will cool down.
The difference between both cases is in the heat conduction capacity of both air and water.
Liquids (and solids) are better <em>thermal conductors </em>than gases because the conduction of heat occurs as result of the direct contact between the particles of matter: the atoms or molecules in hot matter vibrate faster than their neighbors and transmit them kinetic energy by direct contact.
Therefore, the liquid water in the swimming pool, at the same temperature than the air, will be able to absorb more heat in the same time from the body.
In conclusion, the body will cool down faster in water than in air which is why the pool feels cooler than air.
<u>Answer</u>:
The inner walls of a vacuum flask have a silver coating to reduce heat loss by radiation.
<u>Explanation</u>:
The vacuum flask has an inner silver lining to prevent the transfer of heat by radiation. Radiation is a process where the emission or transformation of energy happens in the form of wave or the particles through the material medium.
Vacuum flask being working as thermal insulator helps in maintaining the substance its actual temperature for a long time. The silver lining acts as a reflector .It prevents the heat radiation to released out of the flask.
Answer:
HYDROGEN BONDING
Explanation:HYDROGEN BONDING is the major intermolecular force and interaction taking place when water and ethanol are mixed.
Hydrogen bond is a weak inter-molecular force of attraction which occurs when the partially charged Negative end of an oxygen atom from one oxygen molecule attracts and interacts with the partially charged Positive end of the Hydrogen atom in another Molecule, Hydrogen bonds are also known as dipole-dipole bonds.
