Answer:
1034 yrs
Explanation:
The equation to use in this question is:
t = -2.303/k log (A/A₀) where
A= present number of disintegrations
A₀ = intial number of disintegrations
k = decay constant
The decay constant we will obtain it from the given hal-life:
k: 0.693/t₁/₂, t₁/₂ = half-life ⇒
k: 0.693 / 5730 y = 1.209 x 10⁻⁴ /y⁻¹
t = - 2.303 / 1.209 x 10⁻⁴ /y⁻¹ x log (13.1/15.3) = 1034 yrs
Answer:
Mass percent N₂ = 89%
Mass percent H₂ = 11%
Explanation:
First we <u>use PV=nRT to calculate n</u>, which is the total number of moles of nitrogen and hydrogen:
- 1.03 atm * 7.45 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 305 K
So now we know that
- MolH₂ + MolN₂ = 0.307 mol
and
- MolH₂ * 2 g/mol + MolN₂ * 28 g/mol = 3.49 g
So we have a <u>system of two equations and two unknowns</u>. We use algebra to solve it:
Express MolH₂ in terms of MolN₂:
- MolH₂ + MolN₂ = 0.307 mol
Replace that value in the second equation:
- MolH₂ * 2 g/mol + MolN₂ * 28 g/mol = 3.49
- (0.307-MolN₂) * 2 + MolN₂ * 28 = 3.49
- 0.614 - 2MolN₂ + 28molN₂ = 3.49
Now we calculate MolH₂:
- MolH₂ + MolN₂ = 0.307 mol
Finally, we convert each of those mol numbers to mass, to <u>calculate the mass percent</u>:
- N₂ ⇒ 0.111 mol * 28 g/mol = 3.108 g N₂
- H₂ ⇒ 0.196 mol * 2 g/mol = 0.392 g H₂
Mass % N₂ = 3.108/3.49 * 100% = 89.05% ≅ 89%
Mass % H₂ = 0.392/3.49 * 100% = 11.15% ≅ 11%
Answer:
a
No
b
100 mm Hg
Explanation:
From the question we are told that
The vapor pressure of CHCl3, is 
The temperature of CHCl3 is 
The volume of the container is 
The temperature of the container is 
The mass of CHCl3 is m = 0.380 g
Generally the number of moles of CHCl3 present before evaporation started is mathematically represented as
Here M is the molar mass of CHCl3 with the value 
=> 
=> 
Generally the number of moles of CHCl3 gas that evaporated is mathematically represented as
Here R is the gas constant with value 
So
Given that the number of moles of CHCl3 evaporated is less than the number of moles of CHCl3 initially present , then it mean s that not all the liquid evaporated
At equilibrium the temperature of CHCl3 will be equal to the pressure of air so the pressure at equilibrium is 100 mmHg
Six protons, six electrons, and six neutrons. The atom you are looking for is Carbon. The mass number is 12.
Mass number = protons + neutrons
