Why is the cathode ray tube connected to a vacuum pump?
1 answer:
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Answer:
Explanation:
Let A₀ = the original amount of ⁵⁵Co .
The amount remaining after one half-life is ½A₀.
After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.
After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.
The general formula for the amount remaining is:
A =A₀(½)ⁿ
where n is the number of half-lives
n = t/t_½
Data:
A = 1.90 ng
t = 45 h
t_½ = 18.0 h
Calculation:
(a) Calculate n
n = 45/18.0 = 2.5
(b) Calculate A
1.90 = A₀ × (½)^2.5
1.90 = A₀ × 0.178
A₀ = 1.90/0.178 = 10.7 ng
The original mass of ⁵⁵Co was .
Answer:
The volume of the neon gas is 17.07 L.
Explanation:
The ideal gas equation describes the relationship among the four variables P, V, T, and n. An ideal gas<u> is a hypothetical gas whose pressure-volume-temperature behavior can be completely accounted for by the ideal gas equation</u>.
In order to calculate the volume, first we need to convert the grams of neon to moles:
28.18 g Ne ------ 1 mol Ne
5.0 g Ne---------- <u>x= 0.25 mol Ne</u>
Now, using the ideal gas equation we calculate the volume:
V= 17.07 L