Answer:
72.57 grams
Explanation:
The mass percentage of gold in the ore is 0.19 %
The mass of ore used = 23 kg
The mass of gold in the ore = 
moles of gold in the given mass of ore =
As per given equation four moles of Au is giving four moles of complex compound on reacting with NaCN
Then in second reaction two moles of the complex is reacting with one mole of Zinc
Thus two moles of gold are reacting with one mole of Zinc
The moles of Zinc needed = 0.5 X 2.22 mol = 1.11 moles
The mass of Zinc needed = moles X atomic mass =1.11 X 65.38 = 72.57 grams
Answer:
P = 559.553 mmHg
Explanation:
Clasius-Clapeyron:
- Ln(P2/P1) = - ΔHv/R [ 1/T2 - 1/T1 ]
∴ P1 = 23.8 mmHg = 3.173 KPa
∴ T1 = 25°C ≅ 298 K
∴ ΔHv = 40.657 KJ/mol
∴ R = 8.314 E-3 KJ/K.mol
∴ T2 = 96°C ≅ 369 K
⇒ Ln P2/P1 = - (40.657 KJ/mol/8.314 E-3 KJ/K,mol) [(1/369 K) - (1/298 K) ]
⇒ Ln P2/P1 = - (4890.185 K) [ - 6.457 E-4 K-1 ]
⇒ Ln P2/P1 = 3.1575
⇒ P2/P1 = 23.511
⇒ P2 = (23.511)(3.173 KPa)
⇒ P2 = 74.601 KPa = 559.553 mmHg
When a substance changes into a different substance, you are observing its chemical properties.
In a physical change, the substance must <em>not </em>change into a different substance.
The physical and chemical properties of a substance do <em>not</em> change.
Using the VSPER theory, the effect of lone pairs on molecular shape can be discussed.
There are 3 types of electron pairs present in a molecular shape: bond pair -bond pair, lone pair - bond pair, lone pair - lone pair.
Strength of repulsions between these three types of pair follows the order:
lone pair- lone pair > lone pair - bond pair > bond pair - bond pair
Whenever there is an addition of lone pairs to the geometry, some distortions take place which decreases the bond angles and some asymmetry is attained in the original molecular shape.
Answer:
B
Explanation:
Noble gases are in group 18 (neon, argon, etc)
