What is the missing part of the equation below?

Chemistry

2 answers:

Trava [24]2 years ago

4 0

Answer:

A) ⁴He₂

Explanation:

²³⁸U₉₂ → ²³⁴Th₉₀ + A

To obtain the missing element (A), we have to first find it's atomic and mass numbers.

The mass number is the sum total of the protons and neutrons in an atom. It is usually equal to the superscript in an atom. for example in ²³⁸U₉₂ the mass number is 238.

The atomic number is the total of the protons in an atom. It is usually equal to the subscript in an atom. for example in ²³⁸U₉₂ the atomic number is 92.

In a chemical eqation, there's conservation of mass.

With this, mass number of products = mass number of reactants. same thing for the atomic number.

Mass number of Product = 238

Mass number of Reactant = 234 + x

238 = 234 + x

x = 238 - 234 = 4

Atomic number of product = 92

Atomic number of reactant = 90 + y

92 = 90 + y

y = 92 -90 = 2

So the atomic number of the missing element is 2 and its mass number is 4. ⁴A₂.

Among the elements, the only match is ⁴He₂. So the correct option is A

Illusion [34]2 years ago

3 0

A. Missing part is ⁴He₂

You can also calculate it by adding/subtracting for atomic mass & atomic numbers

Hope this helps!

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Alveoli are tiny sacs of air in the lungs. Their average diameter is 4.50 × 10−5 m. Calculate the uncertainty in the velocity of

Arisa [49]

Answer: The uncertainty in the velocity of oxygen molecule is $4.424\times 10^{-5}m/s$

Explanation:

The diameter of the molecule will be equal to the uncertainty in position.

The equation representing Heisenberg's uncertainty principle follows:

$\Delta x.\Delta p=\frac{h}{2\pi}$

where,

$\Delta x$ = uncertainty in position = d = $4.50\times 10^{-5}m$

$\Delta p$ = uncertainty in momentum = $m\Delta v$

m = mass of oxygen molecule = $5.30\times 10^{-26}kg$

h = Planck's constant = $6.627\times 10^{-34}kgm^2/s^2$

Putting values in above equation, we get:

$4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg\times \Delta v=\frac{6.627\times 10^{-34}kgm^2/s}{2\times 3.14}\\\\\Delta v=\frac{6.627\times 10^{-34}kgm^2/s^2}{2\times 3.14\times 4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg}=4.424\times 10^{-5}m/s$