Answer:
1) chemical indicators won't work above it's pH range so therefore it probably won't change colour.
2) the solution should be clear and colourless to see colour change.
3) indicators tend to be of low accuracy so it's not 100% reliable.
The last row going across
Answer:
Mn (s) + NiCl2 (aq) → MnCl2 (aq) + Ni
Explanation:
The order of displacement of metals from aqueous solution by another metal is defined by the activity series of metals.
The activity series arranges metals in order of reactivity and increasing electrode potentials. The less negative the electrode potential of a metal is, the less reactive it is and the lower it is found in the activity series.
Nickel has a less negative electrode potential than manganese hence it is displaced from an aqueous solution of its salt by manganese spontaneously.
Answer:
ΔH°_rxn = -195.9 kJ·mol⁻¹
Explanation:
4NH₃(g) + 3O₂(g) ⟶ 2N₂(g) +6H₂O(g)
ΔH°_f/(kJ·mol⁻¹): -45.9 0 0 -241.8
The formula relating ΔH°_rxn and enthalpies of formation (ΔH°_f) is
ΔH°_rxn = ΣΔH°_f(products) – ΣΔH°_f(reactants)
ΣΔH°_f(products) = -6(241.8) = -1450.8 kJ
ΣΔH°_f(reactants) = -4(45.9) = -183.6 kJ
ΔH°_rxn = (-1450.8 + 183.6) kJ = -1267.2 kJ
