Which quantity of heat is equal to 200. joules

Uranium-238 decays to lead-206 with a half-life of 4.5 x 109 yr. Determine how much uranium-238 decays in milligrams (to three s

Mamont248 [21]

Answer:

2.15 mg of uranium-238 decays

Explanation:

For decay of radioactive nuclide-

$N=N_{0}.(\frac{1}{2})^{\frac{t}{t_{\frac{1}{2}}}}$

where N is amount of radioactive nuclide after t time, $N_{0}$ is initial amount of radioactive nuclide and $t_{\frac{1}{2}}$ is half life of radioactive nuclide

Here $N_{0}=4.60 mg$ , $t=4.1\times 10^{9}yr$ and $t_{\frac{1}{2}}=4.5\times 10^{9}yr$

So, $N=(4.60mg)\times (\frac{1}{2})^{\frac{4.1\times 10^{9}}{4.5\times 10^{9}}}$

so, N = 2.446 mg

mass of uranium-238 decays = (4.60-2.446) mg = 2.15 mg

3 0

2 years ago

6. According to Crystal Field Theory, what should be the color of an aqueous solution of the ion [Y(H2O)6]3

UkoKoshka [18]

Answer:

Colourless

Explanation:

We know that Y^3+ has the electronic configuration of;

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 (the 5s and 4d levels are empty).

According to the crystal field theory, the colour of complexes result from transitions between incompletely filled d orbitals.

As a result of this, complexes with empty or completely filled d orbitals are colourless. Thus, [Y(H2O)6]3 is colourless according to the Crystal Field Theory.

4 0

2 years ago

3) During the day at 27°C a cylinder with a sliding top contains 20.0 liters

tatiyna

Answer:

$T_2=12\°C$

Explanation:

Hello there!

In this case, according to the Charles' law equation which help us to understand the directly proportional relationship between volume and temperature:

$\frac{T_2}{V_2}=\frac{T_1}{V_1}$

Thus, by solving for the final temperature, T2, and making sure we use the temperatures in Kelvin, we can calculate the final temperature as shown below:

$T_2=\frac{T_1V_2}{V_1} \\\\T_2=\frac{(27+273)K*19L}{20.0L}\\\\T_2=285-273\\\\T_2=12\°C$