Astatine-218 has a half-life of 1.6 seconds. If you begin with a 1.7 g sample of astatine-218, how much of the sample remains after 3.2 seconds?​

Answer:d

Explanation:

Answer:

d] 74.1 cm²

Explanation:

Product means that the values given must be multiplied.

13 cm × 5.7 cm = 74.1 cm²

Let's check the equation

[tex]\\ \sf\longmapsto {CH_4\atop 1mol}+{4S\atop 4moles}\longrightarrow {CS_2\atop 1mol}+{2H_2S\atop 2moles}[/tex]

[tex]\\ \sf\longmapsto 10.6(0.25)=2.65moles\:of\:CS_2[/tex]

Archaea (Archaeon ): Single-celled microorganisms without nuclei and with membranes different from all other organisms. Once thought to be bacteria.

Unicellular organism

-A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms.

a.

The atomic radius of iridium is 1.355 Å

For a face-centered cubic unit cell, with edge length, a and atomic radius r,

we have a² + a² = (4r)²

2a² = 16r²

r² = a²/8

r = a/√8

Since a = 3.833 Å,

Substituting this into the equation, we have

r = a/√8

r = 3.833 Å/√8

r = 3.833 Å/2.828

r = 1.355 Å

So, the atomic radius of iridium is 1.355 Å

b.

The density of iridium metal is 22.67 g/cm³

To find the density of the iridium metal, we need to find the mass of atoms per unit cell.

So, for the face centered cubic iridium atom, there are 6 faces per unit cell × 1/2 atoms per face + 4 corners per unit cell × 1/4 atoms per corner = 3 atoms + 1 atom = 4 atoms per unit cell.

So, the mass of the atoms in the unit cell is m = number of atoms/cell × number of moles/atom × molar mass of Iridium

= 4 atoms/cell × 1 mol/6.022 × 10²³ atoms × 192.22 g/mol

= 768.88/6.022 × 10²³ g/cell

= 127.68 × 10⁻²³ g/cell

= 1.2768 × 10⁻²¹ g/cell

Next, we need to find the volume of the unit cell which is V = a³

= (3.833 Å)³

= (3.833 × 10⁻¹⁰ m)³

= 56.314 × 10⁻³⁰ m

= 5.6314 × 10⁻²⁹ m

So, the density of iridium = mass of unit cell/volume of unit cell

= m/V

= 1.2768 × 10⁻²¹ g/cell ÷ 5.6314 × 10⁻²⁹ m

= 0.2267 × 10⁸ g/m³

= 0.2267 × 10⁸ g/m³ × 10⁻⁶ m³/cm³

= 0.2267 × 10² g/cm³

= 22.67 g/cm³

So, the density of iridium metal is 22.67 g/cm³

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The cart with the greatest change in speed is the cart with a mass of 75 Kg

Acceleration is defined as the change in velocity of an object with time. Also, acceleration is related to the force and mass according to the following equation:

Acceleration (a) = Force (F) / mass (m)

To answer the question, we shall determine the acceleration of each cart.

a = F / m

a = 200 / 75

a = F / m

a = 200 / 125

a = F / m

a = 200 / 350

a = F / m

a = 200 / 450

From the above illustrations, we can see that the cart with a mass of 75 K has the greatest change in speed (i.e 2.67 m/s²)

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Answer:

D

Explanation:

F. 200-75=125

G. 20-125=75

H. 350-200=150

J. 450-200=250

250 is the biggest number so it has the biggest change

Answer:

where are the answers?

Explanation:

Answer:

True

Explanation:

its true don't lie on here please

In giant covalent structures such as graphite or diamond, the atoms form strong bonds by sharing electrons. Therefore, the given statement is true.

A covalent bond can be defined as a chemical connection formed by the sharing of electron sets between particles. A covalent bond can be created by the mutual sharing of electrons from both atoms.

The pair of electrons that are shared in this kind of bonding is known as the shared or bonding pair. Covalent bonds are the sharing of bonding pairs of electrons that will provide the stability of the atom in its outer shell.

Elements that have very high ionization energies are incapable of exchanging electrons or elements having low electron affinity cannot accept electrons. Covalent bonding between two non-metallic atoms is characterized by the equal sharing of electrons between the atoms and covalent bonds with an electronegativity difference of participating atoms is more than 2.0.

Therefore, a giant structure like a diamond has strong covalent bonds that require a lot of energy to break.

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#SPJ2

Answer:

Molecule.

Explanation:

carbon and fluorine. Based on the bonding, a unit of carbon dioxideis described as a molecule.

Answer:

0.185moles

Explanation:

1mole of bicarbonate produces 1mole of CO2

so 0.185 mole produces 0.185 moles of CO2

C9H8O. .....................

Answer:

the left one

Explanation:

heavier means it goes faster

Answer:

Soda and wine is the answer to your question.

Explanation:

yo make salt you need a base and an acid. in this case the base is soda and the wine is acid. hope that helps :)

Answer:

C. Al and O2

Explanation:

The reactants are the elements or compounds that is becoming the result

So Al and O2

Hope this helps!

Answer:

Mass of 0.5 moles of CO2 is 22 gm.

Explanation:

1 mole of CO2 = 44 gm

0.5 mole of CO2 = 0.5 × 44 = 22 gm

Answer:

Quadrilateral because there is no parallel and equal

Answer:

Dived the numbers by each other

Explanation:

25.3/19.9

Answer:

It is strongly recommended that students do NOT wear contacts lenses in the laboratory. Chemical vapors may penetrate the contact lens material and cause the lens to adhere to one's eye, which could be detrimental to the eye. Goggles are not vapor tight and do not completely eliminate this absorption.

A water heater can be regularly maintained by flushing it at least two times in a year.

A water heater is a device that is used to heat up water for home use. There are different types of water heaters but they all serve the same purpose at home. In order to maintain maximum efficiency, the water heater must be maintained regularly.

The following are routine maintenance operations on a water heater;

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Answer:  Antimony: Antimony is used to create firework glitter effects. Barium: Barium is used to create green colors in fireworks,

Explanation:

Answer:

Explanation:Antimony: Antimony is used to create firework glitter effects. Barium: Barium is used to create green colors in fireworks, 

Answer:

Covalent compounds (solid liquid solutions)  

non-metal elements are insulators but not conductors of electricity.

Explanation:

Metal elements and carbon (graphite) are conductors of electricity

Answer:

38 pounds of gold in cubic mile of seawater.

Answer:

Is there be suppose a file with this?

Explanation:

Explanation:

The Mechanical Hound is a robotic animal that firemen can deploy to hunt and catch fugitives. It can be trained and programmed to hunt its prey very quickly by smell. Once it catches its prey, the Hound injects the person with a sedative; unable to run, the drugged fugitive is easily captured.

Answer:

The first thing we have to do is change and state all the units so that we can use our ideal gas law equation ([tex]PV = nRT[/tex]).

650 mmHg is a pressure unit, we have to convert this to kiloPascals. We know that 760 mmHg gives us 101 kPa.

[tex]650 \ mmHg \ * \ \frac{101kPa}{760 mmHg} = 86 \ kPa[/tex]

P = 86kPa

T = 15°C + 273K = 288K

R (Gas constant) = 8.31 kj/mol  

Molar mass of Ammonia ([tex]NH_{3}[/tex]) = (1 x 3) + (14) = 17g/mol

n (moles) = [tex]\frac{mass}{molar \ mass}[/tex] [tex]= \frac{56.8}{17} =[/tex] 3.34 mol

V = ?

Rearrange the equation to solve for Volume:

[tex]V = \frac{nRT}{P}[/tex]

Substitute the values inside:

V = [tex]\frac{(3.34)(8.31)(288)}{(86)} = 93 L (rounded)[/tex]

Therefore 93 L of volume is occupied by the ammonia gas.