Answer:
After 90 minutes 5.15625 g amount left from total of 165 g.
Explanation:
Given data:
Technetium-104 half life = 18.0 min
Total amount of sample = 165 g
Amount left after 90.0 min = ?
Solution:
First of all we will calculate the number of half lives passes.
Number of half lives = T elapsed / Half life
Number of half lives = 90 min /18.0 min
Number of half lives = 5
Amount left:
At time 0 = 165 g
At first half life = 165 g/ 2= 82.5 g
At 2nd half life = 82.5 g/2 = 41.2 g
At 3rd half life = 41.2 g/ 2 = 20.625 g
At 4th half life = 20.625 g/ 2 = 10.3125 g
At 5th half life = 10.3125 g /2 = 5.15625 g
Thus, after 90 minutes 5.15625 g amount left from total of 165 g.
H - 1.01
C - 12.01
0 - 16.00
2(1.01) + 12.01 + 2(16.00) = 46.03 g/mol
Answer :
the amount of heat,in joules, required to increase the temperature of a 49.5-gram sample of wanted from 22°c to 66°c is 9.104 Joules.
Explanation:
The answer can be calculated using the formula
Q = mCрΔT
where
Q is the amount of heat required in joules to raise the temperature.
m is the mass of the sample in Kg.
Cp is the specific heat of the sample in J/Kg°C.
ΔT is the change in temperature required.
Here, m = 49.5-gram = 0.0495 kg
Cp = 4.18 J/Kg°C (for water)
T₁ = 22°C ; T₂ = 66°C
ΔT = 66 - 22 = 44
Substituting values in Q = mCрΔT
Q = (0.0495)(4.18)(44)
Q = 9.104 J
It's not the valences electrons themselves, but the number of valence electrons that determines the chemical properties of an element
