Answer:
The salt is Zn(NO3)2
When the residue is allowed to cool, its colour changes from yellow to white
The equation of the reaction is; 2Zn(NO3)2(s) --->2ZnO(s) + 4NO2(g) + O2(g)
Explanation:
Decomposition of Zn(NO3)2 is one of the routes by which ZnO is obtained. ZnO is a white insoluble powder which has a yellow colour when hot and a white colour when cold. It is an amphoteric substance used as a white pigment in paints and as a filler for rubber.
In a very pure form, it is used in cosmetic powders and creams as well as in medicinal ointments and lotions.
Also recall that NO2 is a brown gas and oxygen gas rekindles a glowing splint.
Single replacement reaction
Since the sign is positive, the entropy increased by 88.48 J/K.
Examine the phases of the species present to determine whether a physical or chemical process will cause an increase or decrease in entropy. Keep in mind "Silly Little Goats" to aid you in telling.
[1 Sf K+1 + 1 Sf Br-1 (aq)] ([1Sf(KBr (s))])
[1(102.5) + 1(82.42)] - [1(96.44)] = 88.48 J/K
If the entropy has grown, we say that Delta S is positive, and if it has dropped, we say that Delta S is negative. Due to its ionic nature, KBr is soluble in water and causes the 'K(+)' ions to hydrate.
Learn more about Entropy here-
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A substance where almost all have the same atomic number of protons
Answer:
The mass of nickel is 48μg
Explanation:
Parts per billion is a way to describe small concentrations and is defined as the ratio between μg of solute and kg of solvent.
If a solution of nickel in propanol is 20ppb, contains 20μg of nickel in 1 kg of propanol.
Thus, a sample of 2.4kg of propanol will contain:
2.4kg × (20μg nickel / 1kg) = 48μg nickel
<h3>The mass of nickel is 48μg</h3>