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3 years ago

How many atoms are found in 12.0 grams of Helium?

2 answers:

3 0

Each mole contains Avagodro's number of atoms i.e. 6.023x10^23, so

3 moles x 6.023x10^23 atoms/mole = 18.069x10^23 atoms = 1.8x19^24 atoms

Furkat [3]3 years ago

3 0

One mole of helium has a mass of 4.0 grams. In 12 grams there are 3 moles of He. Each mole contains 6.022x10^23 atoms of helium. Therefore, 3 moles of He will contain 3 times as many atoms or 1.806x10^24 atoms.

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An element has six valence electrons available for bonding which group of the periodic table does this element most likely belon

professor190 [17]

Elements in groups 16 has six valance electrons.

8 0

3 years ago

Read 2 more answers

An animal can ____.

e-lub [12.9K]

The answer is B!! hope this helps(: an example is a zebra or a lion

4 0

2 years ago

A container is filled with hydrogen gas. It has a volume of 4 liters and a pressure of 2 atm. If the pressure of the container i

Dennis_Churaev [7]

Answer:

1.33 L.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and T are constant, and have different values of P and V:

(P₁V₁) = (P₂V₂)

Knowing that:

V₁ = 4.0 L, P₁ = 2.0 atm,

V₂ = ??? L, P₂ = 6.0 atm.

Applying in the above equation

(P ₁V₁) = (P₂V₂)

∴ V₂ = P ₁V₁/P₂ = (2.0 atm)(4.0 L)/(6.0 atm) = 1.33 L.

4 0

3 years ago

Which element has a smaller ionic radius than magnesium (Mg)?

barxatty [35]

Answer:

Na has atomic number 11

which is less than magnesium has atomic number 12

ANSWER IS D

Explanation:

aluminum or Al is atomic 13 and Ca or calcium is atomic number 20 and rubidium or Rb is atomic number 37

6 0

3 years ago

Consider a 100-gram sample of radioactive cobalt-60.

svetlana [45]

It will take 5.2 years to decay.

The half life of cobalt-60 is 5.2 years. The half life is the time taken for the mass of the substance to decrease by a half.

here, the amount of remaining substance is 50%,

so, $(\frac{1}{2} )^{n} = 0.5$

n. log (0.5) = log (0.5)

n = 1

So it would take 1 half lives to decay this much, which is 1 x 5.2 which is 5.2 years.

what do you mean by radioactive decay ?

The process through which an unstable atomic nucleus loses energy via radiation is known as radioactive decay, also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration. A material that has unstable nuclei is considered as radioactive.

Learn more about decay here:-

brainly.com/question/13853996

#SPJ1

7 0

1 year ago