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Alla [95]
3 years ago
8

A balloon filled with helium gas contains 8.89 moles of helium. How many atoms are present in the balloon? Show all of your work

, including starting quantity, conversion factor, and units.
Chemistry
1 answer:
NNADVOKAT [17]3 years ago
7 0

There are 5.35 × 10²⁴ atoms in 8.89 moles of Helium.

<u>Explanation:</u>

Given that number of moles of Helium = 8.89 moles

Moles and Avogadro's number are related to each other by multiplying those two we can convert moles into atoms, molecules and Particles .

We have to convert the moles into atoms by multiplying the molar amount by Avogadro's number as,

Number of atoms = 8.89 × 6.022 × 10²³ atoms

                             = 5.35 × 10²⁴ atoms

So there are 5.35 × 10²⁴ atoms in 8.89 moles of Helium.

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How many atoms are present in 0.0845 moles of tungsten?
klasskru [66]
1 mole tungsten ------------- 6.02 x 10²³ atoms
0.0845 moles ---------------- ( atoms tungsten )

atoms tungsten = 0.0845 x ( 6.02 x 10²³) / 1

atoms tungsten = 5.08 x 10²² / 1

= 5.08 x 10²² atoms of tungsten

hope this helps!
6 0
3 years ago
Which statements accurately describe Dmitri Mendeleev’s contributions to the development of the periodic table? Check all that a
Varvara68 [4.7K]

Answer:

  • <em><u>Mendeleev produced the first orderly arrangement of known elements.</u></em>

  • <em><u>Mendeleev used patterns to predict undiscovered elements.</u></em>

Explanation:

  • <u>Mendeleev produced the first orderly arrangement of known elements and used patterns to predict the undiscovered elements.</u>

        Those two statments are true.

For the time being there were some 62 known elements. Before Medeleev some schemes to order part of the elements were proposed, but Medeleev showed the relationship between the atomic mass and the properties of the elements (supports second choice). This arrangement is known as the periodic table.

More importantly, Mendeleev predicted correctly the existance and properties of unknown elements, which is his major contribution: he left blanket spaces which where gradually filled when new elements where discovered (this supports the fourth choice).

The first modern chemistry book was written by Antoine Lavoisier (this discards first option).

Mendeleev ordered the elements by increasing mass number (this discards third choice), which was corrected later by the scientist Henry Moseley, who ordered the elements by increasing atomic number (number of protons).

Isotopes were not known by Mendeleev times, so this discards the last option.

8 0
3 years ago
Read 2 more answers
How is the modern periodic table arranged?
oksano4ka [1.4K]
By increasing atomic number
5 0
3 years ago
Which term represents a type of nuclear reaction?
wel
D)natural transmutation
7 0
3 years ago
Read 2 more answers
F 2.50 × 10−2 g of solid Fe(NO3)3 is added to 100. ML of a 1.0 × 10−4 M NaOH solution, will a precipitate form? (ksp=4 × 10−38 f
vladimir1956 [14]

Answer:

A precipitate will be formed

Explanation:

The Ksp equilibrium of Fe(OH)₃ is:

Fe(OH)₃ (s) ⇄ Fe³⁺(aq)+ 3OH⁻(aq)

And its expression is:

Ksp = 4x10⁻³⁸ = [Fe³⁺] [OH⁻]³

<em>Where the concentrations are concentrations in molarity in equilibrium,</em>

We can write Q as:

Q = [Fe³⁺] [OH⁻]³

<em>Where [] are actual concentrations in molarity of each specie.</em>

<em />

When Q>= Ksp; a precipitate is formed,

When Q< Ksp no precipitate is produced:

[OH⁻] = [NaOH] = 1.0x10⁻⁴M

[Fe²⁺] = 2.50x10⁻²g * (1mol / 179.85g) / 0.100L = 1.39x10⁻³M

<em>179.85g/mol is molar mass of Fe(NO₃)₂ and the volume of the solution is 0.100L = 100mL</em>

<em />

Q = [Fe³⁺] [OH⁻]³

Q = [ 1.39x10⁻³] [ 1.0x10⁻⁴]³

Q = 3.8x10⁻¹⁵

As Q >> Ksp; A precipitate will be formed

7 0
3 years ago
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