Answer : 135 grams of sodium has 5.869 moles.
Solution : Given,
Mass of sodium = 135 grams
Molar mass of sodium = 23 g/mole
Formula used :

Now put all the given values in this formula, we get

Therefore, the moles of sodium present in 135 grams of sodium is, 5.869 moles.
T = 14400 s
26.5 x 14400=381600 C
381600/96500=3.95 Faradays
Cu2+ + 2e- = Cu
3.95 faradays ( 1 mol/ 2 Faradays) = 1.97
mass = 1.97 x 63.55 g/mol=125 g
moles Au = 33.1 / 196.967 g/mol=0.168
Au+ + 1e- = Au
0.168 ( 1 Faraday/ 1mol)= 0.168 Faraday
0.168 x 96500=16217 Coulombs
16217 / 5.00=3243 s => 54 min
Melting? not really sure what type of answer they are going for but the substance is going through the melting phase
K₂CrO₄(aq) + Ba(NO₃)₂(aq) = BaCrO₄(s) + 2KNO₃(aq)
2K⁺ + CrO₄²⁻ + Ba²⁺ + 2NO₃⁻ = BaCrO₄ + 2K⁺ + 2NO₃⁻
spectator ions: K⁺, NO₃⁻