Answer: 2.186 m
Explanation:
formula for molality: (mol solute)/(kg solvent)
Na2CO3 = solute
510g Na2CO3 * ( 1 mol / 106 g) = 4.811 mol solute
ethylene glycol = solvent
2.2 * 10^3 g * ( 1 kg / 1000 g) = 2.2 kg
(4.811/2.2) = 2.186
3 elements are in one chemical
Answer:
KO is the limiting reactant.
0.11 mol O₂ will be produced.
Explanation:
4 KO₂ + 2 H₂O ⇒ 4 KOH + 3 O₂
Find the limiting reagent by dividing the moles of the reactant by the coefficient in the equation.
(0.15 mol KO₂)/4 = 0.0375
(0.10 mol H₂O)/2 = 0.05
KO₂ is the limiting reagent.
The amount of product produced depends on the limiting reagent. To find how much is produced, take moles of limiting reagent and multiply it by the ratio of reagent to product. You can find the ratio by looking at the equation. For every 4 moles of KO₂, 3 moles of O₂ are produced.
0.15 mol KO₂ (3 mol O₂)/(4 mol KO₂) = 0.1125 mol O₂
0.11 mol O are produced.
Answer: Amount of Gallium = 0.127g
Explanation:
Electrolysis equation is:
Ga3+ + 3e- ------> Ga
To calculate the charge
t = 40.0 min = 40.0 x 60 s = 2400 s
time, t = 2400s
Q = I*t =
= 0.22A x 2400s
= 528 C
1 mol of Ga requires 3 mol of electron
1 mol of electron = 1 Faraday =96485 C
So,1 mol of Ga requires 96485x 3= 289455 C
mol of Gallium = 528/289455 = 0.00182 mol
Molar mass of Ga = 69.72 g/mol
mass of Ga = number of moles x molar mass
= 0.00182mol * 69.72
g/mol
= 0.127g
or you can use this direct formula
m=(current*time/Faraday's)*(molar mass/no of electrons transferred)
keeping in mind Ga3+ + 3e- → Ga
n=3
m=(It/F)*(mew/n)
m =(0.22 x 2400/96485) x (69.72/3)
m=0.127 g
