Answer:
ion exchange is the exchange of ions of the same charge between an insoluble solid and a solution in contact with it, used in water-softening and other purification and separation processes.
Explanation:
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Answer:
Explanation:
Half life of Nobelium-253 is 97 seconds . That means after every 97 seconds half of the Nobelium amount will be disintegrated .
Time taken in bringing the sample to laboratory = 291 seconds
291 second = 291 / 97 half life
n = 3
N = 
N₀ is original mass , N is mass after n number of half life.
N = 5 mg x 
= .625 mg
Only 0.625 mg of Nobelium-253 will be left .
Answer:
c. Mercury is used in barometers because it has a high density
Explanation:
Chemical change -
It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .
The indication of any chemical change is the formation of some new substance.
Hence, from the question,
The process which does not involve chemical change is -
The use of mercury in barometer , to measure pressure , in this process no new substance is formed i.e. , now change in mercury.
Chemical reaction: 2Mg + O₂ → 2MgO. ΔH = -1204 kJ.
ΔH(reaction) = -233 kJ.
From chemical reaction we can se that two moles of magnesium oxide produce -1204 kJ, make proportion:
2 mol : -1204 kJ = n(MgO) : -233 kJ.
n(MgO) = 0,387 mol.
m(MgO) = n(MgO) · M(MgO).
m(MgO) = 0,387 mol · 40,3 g/mol.
m(MgO) = 15,596 g.
Answer:
20atm
Explanation:
according to boyles law P1V1= P2V2