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quester [9]
3 years ago
15

How many neutrons does element X have if its atomic number is 23 and its mass number is 90?

Physics
2 answers:
givi [52]3 years ago
4 0

Answer:

67

Explanation:

- The atomic number (Z) of an atom is equal to the number of protons in the nucleus

- The mass number (A) of an atom is equal to the sum of protons and neutrons in the nucleus

Therefore, calling p the number of protons and n the number of neutrons, for element X we have:

Z = p = 23

A = p + n = 90

Substituting p=23 into the second equation, we find the number of neutrons:

n = 90 - p = 90 - 23 = 67

Zina [86]3 years ago
4 0
<h2>Answer:</h2>

<u>The number of neutrons is </u><u>67</u>

<h2>Explanation:</h2>

As we know that the atomic number is the number of protons. If we subtract the atomic number from the mass number, we can actually find the number of neutrons.

So

Number of neutrons = Mass number - atomic number

Neutrons = 90 - 23 = 67

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Determine the kinetic energy of a 2000 kg roller coaster car that is moving at the speed of 10 ms
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\boxed {\boxed {\sf 100,000 \ Joules}}

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Kinetic energy is energy due to motion. The formula is half the product of mass and velocity squared.

E_k= \frac{1}{2} mv^2

The mass of the roller coaster car is 2000 kilograms and the car is moving 10 meters per second.

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Substitute these values into the formula.

E_k= \frac{1}{2} (2000 \ kg ) \times (10 \ m/s)^2

Solve the exponent.

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E_k= 1000 \ kg  \times (100 \ m^2/s^2)

Multiply again.

E_k= 100,000 \ kg*m^2/s^2

  • 1 kilogram square meter per square second is equal to 1 Joule.
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Answer:

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