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3 years ago

Which of the following are true about the SETI program?

1 answer:

3 0

B and D. SETI stands for "Search for Extra Terrestrial Intelligence". They use satellite dishes (like the big one in Areciebo) to listen for any signals aliens might be sending us.

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Radioactive decay can be described by the following equation where is the original amount of the substance, is the amount of the

soldi70 [24.7K]

Answer:

Iron remains = 17.49 mg

Explanation:

Half life of iron -55 = 2.737 years (Source)

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{2.737}\ year^{-1}$

The rate constant, k = 0.2533 year⁻¹

Time = 2.41 years

$[A_0]$ = 32.2 mg

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

So,

$[A_t]=32.2\times e^{-0.2533\times 2.41}\ mg$

$[A_t]=32.2\times e^{-0.610453}\ mg$

$[A_t]=17.49\ mg$

<u>Iron remains = 17.49 mg</u>

8 0

3 years ago

How can you tell the difference between non metals from metals on the periodic element chart with no colors

Leni [432]

You can tell the difference by How shiny it is and by how heavy it is

6 0

3 years ago

The element Osminum has a density of 22.6 g/cm3. the mass of a block of Osmium with three sides of 1.01cmx0.223 cm x 0.648 cm is

Alika [10]

Volume of osmium = 1.01(0.223)(0.648) = 0.14595 cm3

Density = mass / volume
So density x volume = mass of osmium
22.6 x 0.14595 = 3.29845 g

6 0

3 years ago

For the 52nd electron must pair with one of the<br> electrons in the 5p orbital.

Umnica [9.8K]

Answer:

This question is incomplete

Explanation:

This question is incomplete, however, the element that has 52 electrons only is Tellurium (Te) and when the electronic configuration of elements with more than 52 electrons are written, the 52nd electron is indicated/paired the same way the 52nd electron of Te is indicated/paired. Hence, while writing the electronic configuration of Te, it is written as

[Kr] 4d¹⁰ 5s² 5p⁴ where [Kr] is the electronic configuration of krypton. Based on this, we can deduce that the 52nd electron will be in the first orbital of the P subshell (as attached in the picture). This is because when indicating the electrons in the subshell, one electron will be spread across each orbital and if any electron is still remaining, it will be added starting from to the first orbital of the subshell, however no two electrons in an orbital in a subshell can have the same spin and hence must face opposite direction based on pauli's exclusion principle (as seen in attached); thus for the 5p-orbital of elements with 52 or more electrons, when one electron each is represented in each box (3 boxes in total) in the 5p-orbital, the remaining electron is paired with the the first electron in the first box of the 5p-orbital

5 0

4 years ago

Methane is a major component of natural gas, which is used as a fuel in homes. write a balanced equation for the complete oxidat

Likurg_2 [28]

CH4 +2 O2 ----> CO2 +2H2O

8 0

4 years ago