The percentage abundance is a measure of ratio of the number of each isotope and the total number of the element. The percentage abundance of each isotope is :
- Le - 19 = 0.32
- Le - 17 = 0.44
- Le - 15 = 0.24
Number of each isotope in the sample :
- Le - 19 = 16
- Le - 17 = 22
- Le - 15 = 12
Total number of sample = 50
The percentage natural abundance of the isotopes can be calculated :
Number of each isotope ÷ total number of sample
Percentage abundance of Le isotopes
- Le - 19 =
- Le - 17 =
- Le - 15 =
Therefore, the percentage abundance of Le - 19, Le - 17 and Le - 15 isotopes are 0.32, 0.44 and 0.24 respectively.
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Answer:
B. Equal to 7.
Explanation:
Hydrobromic acid is a strong acid that decreases pH and ammonia is a strong base that increases pH.
As the initial pH of water is 7,0 the addition of 35.0mL of 0.400M HBr will produce a pH less than 7,0. But, the same effect of decreasing pH is reverted for the addition of 35.0mL of 0.400M HNO3.
That means the net effect of the two addition is to have a pH:
B. Equal to 7.
I hope it helps!
ENERGY WOULD BE RELALISED, MEANING BONDS ARE BEING BROKEN, SO IT IS AN EXOTHERMIC REACTION
Given:
n = 12 moles of oxygen
T = 273 K, temperature
p = 75 kPa, pressure
Use the ideal gas law, given by
where
V = volume
R = 8.3145 J/(mol-K), the gas constant
Therefore,
Answer: 0.363 m³
