Answer:
4.823 x 10^-19 J
Explanation:
Energy is calculated by E = hv where h - Planck's constant in joule.s
v - frequency.
in this particular question the wave length is 4.12 x 10^-7 m. to exhaustively use this we need a relation between wave length & frequency. c=wv where C is approximately 3 x 10^8m/s
-v = c/w = 3x10^8m/s / 4.12 x 10^-7m = 7.28 x 10^14 Hz or 1/sec
now we can simply use Planck's constant in E=hv =
(6.626 x 10^-34) x (7.28 x 10^14Hz) = 4.823 x 10^-19 J.
Answer:
Number of moles of solute = 0.6 mole
Mass =13.8 g
Explanation:
Given data:
Number of moles of sodium = ?
Volume = 2.0 L
Molarity = 0.30 M
Mass in gram of sodium= ?
Solution:
<em>Number of moles:</em>
Molarity = number of moles of solute / volume in litter
Number of moles of solute = Molarity × volume in litter
Number of moles of solute = 0.30 M × 2.0 L
Number of moles of solute = 0.6 mole
<em>Mass in gram:</em>
Mass = Number of moles × molar mass
Mass = 0.6 mole× 23 g/mol
Mass =13.8 g
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We can calculate the final temperature from this formula :
when Tf = (V1* T1) +(V2* T2) / (V1+ V2)
when V1 is the first volume of water = 5 L
and V2 is the second volume of water = 60 L
and T1 is the first temperature of water in Kelvin = 80 °C +273 = 353 K
and T2 is the second temperature of water in Kelvin = 30°C + 273= 303 K
and Tf is the final temperature of water in Kelvin
so, by substitution:
Tf = (5 L * 353 K ) + ( 60 L * 303 K) / ( 5 L + 60 L)
= 1765 + 18180 / 65 L
= 306 K
= 306 -273 = 33° C
