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3 years ago

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What is the total number of neutrons in an atom of an element that has a mass number of 19 and an atomic number of 9?

1 answer:

FromTheMoon [43]3 years ago

7 0

Your answer should be B.) 10

The atomic mass of an element is the sum of the element's protons and neutrons. The atomic number of an element is equal to its number of protons. To find the amount of neutrons in an atom, subtract the atomic number from the atomic mass. 19 - 9 = 10.

Hope this helps!

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Answer:

<em>The second ball has four times as much kinetic energy as the first ball.</em>

Explanation:

<u>Kinetic Energy </u>

Is the type of energy an object has due to its state of motion. It's proportional to the square of the speed.

The equation for the kinetic energy is:

$\displaystyle K=\frac{1}{2}mv^2$

Where:

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v = speed at which the object moves

The kinetic energy is expressed in Joules (J)

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The kinetic energy of the first ball is:

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$\displaystyle K_1=\frac{1}{2}m\cdot 900$

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The kinetic energy of the second ball is:

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To find out how much, we find the ratio:

$\displaystyle \frac{K_2}{K_1}=\frac{1800m}{450m}$

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