Half life is the time taken by a radioactive isotope to decay by half its original mass.
The original mass is 200 g
Time taken is 60 hours
Final mass is 25 g
Therefore;
Final mass = Original mass × (1/2)^n; where n is the number of half lives.
25 = 200 (1/2)^n
1/8 = (1/2)^n
n = 3
Three half lives = 60 hours
1 half lives = 20 hours
Therefore; the half life of the radioactive nucleus is 20 hours
Answer:
represents the additional driving force required to overcome barriers such as the large activation energy for the formation of a gas at a metal surface.
Answer:-
2328.454 grams
Explanation:-
Volume V = 18.4 litres
Temperature T = 15 C + 273 = 288 K
Pressure P = 1.5 x 10^ 3 KPa
We know universal Gas constant R = 8.314 L KPa K-1 mol-1
Using the relation PV = nRT
Number of moles of oxygen gas n = PV / RT
Plugging in the values
n = (1.5 x 10^3 KPa ) x ( 18.4 litres ) / ( 8.314 L KPa K-1 mol-1 x 288 K)
n = 11.527 mol
Now the balanced chemical equation for this reaction is
2KNO3 --> 2KNO2 + O2
From the equation we can see that
1 mol of O2 is produced from 2 mol of KNO3.
∴ 11.527 mol of O2 is produced from 2 x 11.527 mol of KNO3.
= 23.054 mol of KNO3
Molar mass of KNO3 = 39 x 1 + 14 x 1 + 16 x 3 = 101 grams / mol
Mass of KNO3 = 23.054 mol x 101 gram / mol
= 2328.454 grams
Cars might not be as insulated and as safe because of the need to get cooler air into the vehicle, and im not fully sure but refrigerators would still run on ice to cool food. Houses wouldnt be as insulated from heat so when winter came around you would be colder than normal <span />
Answer:
For 2. the answer is 15.0 mL
For other examples, you can solve by exact way as I have solved the 2nd example.
I have writen down all the balanced chemical reaction equation for examples 1, 3, 4, 5 for you. ( picture 2 )
Explanation:
Please see the step-by-step solution in the picture attached below.(picture 1)
Hope this answer can help you. Have a nice day!
