<span>Selenium has 6 valence electrons, shares four of them with the four F atoms and has a pair of electrons left over, so has l0 electrons in its outer energy level. Choice A</span>
Answer:
6 moles of C atoms, 12 moles of H atoms and 6 moles of O atoms
Explanation:
A chemical formula represents the number of moles of atoms presents in 1 mole of the compound.
For example, for 1 mole:
CₐHₓ, you have a moles of carbon and x moles of hydrogen.
Thus, for the molecule:
C₆H₁₂O₆, you have <em>6 moles of C atoms, 12 moles of H atoms and 6 moles of O atoms</em>
Answer:
Ca(OH)2 will not precipitate because Q<Ksp
Explanation:
Ksp for Ca(OH)2 has already been stated in the question as 8.0 x 10-8mol2dm-6
The value of the reaction quotient depends heavily on the concentration of the reactants. As the initial concentration of the calcium carbide decreases considerably, the reaction quotient decreases until Q<Ksp hence the Ca(OH)2 will not precipitate from solution.
The reaction equation is:
CaC₂(s) + H₂O ⇒ Ca(OH)₂ + C₂H₂
From
Ca(OH)2= Ca2+ + 2OH-
Concentration of solution= 0.064×1/64= 1×10-3
Since [Ca2+] = 1×10-3
[OH-]= (2×10-3)^2= 4×10^-6
Hence Q= 4×10^-9
This is less than the Ksp hence the answer.
Answer:
Explanation:
Given:
Pressure = 745 mm Hg
Also, P (mm Hg) = P (atm) / 760
Pressure = 745 / 760 = 0.9803 atm
Temperature = 19 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (19 + 273.15) K = 292.15 K
Volume = 0.200 L
Using ideal gas equation as:
where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 0.0821 L.atm/K.mol
Applying the equation as:
0.9803 atm × 0.200 L = n × 0.0821 L.atm/K.mol × 292.15 K
⇒n = 0.008174 moles
From the reaction shown below:-
1 mole of 
react with 2 moles of 
0.008174 mole of react with 2*0.008174 moles of
Moles of = 0.016348 moles
Volume = 13.4 mL = 0.0134 L ( 1 mL = 0.001 L)
So,
