A 36.0−g sample of an unknown metal at 99°C was placed in a constant-pressure calorimeter containing 70.0 g of water at 24.0°C.
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Answer:
0.41 moles.
Explanation:
Given that:
Mass of helium = 4.00 g
Initial Volume = 24.4 L
initial Temperature = 25.0 °C =( 25 + 273) = 298 K
initial Pressure = 1.00 atm
The volume was reduced to :
i.e
final volume of the helium - 10.4 L
Change in ΔV = 24.4 - 10.4 = 10.0 L
Temperature and pressure remains constant.
The new quantity of gas can be calculated by using the ideal gas equation.
PV = nRT
n =
n =
n = 0.4089 moles
n = 0.41 moles.
Answer:
Explanation:
Half life of Nobelium-253 is 97 seconds . That means after every 97 seconds half of the Nobelium amount will be disintegrated .
Time taken in bringing the sample to laboratory = 291 seconds
291 second = 291 / 97 half life
n = 3
N =
N₀ is original mass , N is mass after n number of half life.
N = 5 mg x
= .625 mg
Only 0.625 mg of Nobelium-253 will be left .