Answer:
i. n = 5
ii. ΔE = 7.61 × 
KJ/mole
Explanation:
1. ΔE = (1/λ) = -2.178 × 
(
- 
)
(1/434 × 
) = -2.178 × (
)
⇒ 434 × = (1/-2.178 × )
But, 
= 2
434 × = (1/2.178 × )
434 × × 2.178 × = 
⇒ 
= 5
Therefore, the initial energy level where transition occurred is from 5.
2. ΔE = hf
= (hc) ÷ λ
= (6.626 × 10−34 × 3.0 × 
) ÷ (434 × )
= (1.9878 × 
) ÷ (434 × )
= 4.58 × 
J
= 4.58 × 
KJ
But 1 mole = 6.02×
, then;
energy in KJ/mole = (4.58 × KJ) ÷ (6.02×)
= 7.61 × KJ/mole
Answer:
0.077 M
Explanation:
Data Given :
The concentration of half normal (NaCl) saline = 0.45g / 100 g
So,
Volume of Solution = 100 g = 100 mL
Volume of Solution in Liter = 100 mL / 1000
Volume of Solution = 0.1 L
molar mass of NaCl = 58.44 g/mol
Molarity:
Molarity is the representation of the solution. It is amount of solute in moles per liter of solution and represented by M
Formula used for Molarity
M = moles of solute / Liter of solution . . . . . . . . . . (1)
Now to find number of moles of Nacl
no. of moles of NaCl = mass of NaCl / molar mass
no. of moles of NaCl = 0.45g / 58.44 g/mol
no. of moles of NaCl = 0.0077 g
Put values in the eq (1)
M = moles of solute / Liter of solution . . . . . . . . . . (1)
M = 0.0077 g / 0.1 L
M = 0.077 M
So the molarity of half-normal saline solution (0.45% NaCl) = 0.077 M
Sodium-22 remain : 1.13 g
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g
Answer:
Aluminium
Explanation:
Ionization energy is the amount of energy needed to remove an electron from a gaseous atom to form a gaseous ion.
The difference between the third and fourth ionization energies is great. This indicates a group III element which is in the third period.
This element is Aluminium (Al)
