Answer: 6.02214076 atoms Ca
Explanation:
Ca is monoatomic, so atoms in 1 mol = avogadro number
<span>The elastic potential energy stored in the stretched rubber band changes to kinetic energy.</span>
<span><em>Answer:</em>
A strontium-90 atom that has a lost two electrons has <u>38</u> protons, <u>52</u> neutrons, and <u>36</u> electrons.
<em>Explanation:
</em>Atomic number<em> of </em>Strontium (Sr) is 38.
<em>Atomic number = number of protons
</em>Hence, Strontium has 38 protons.
If the element is in neutral state,
number of protons = number of electrons.
Then, neutral Strontium atom should have 38 electrons.
But the question says Sr has lost 2 electrons. Hence, number of electrons should be 38 - 2 = 36.
Mass number = number of protons + number of neutrons.
The given mass number is 90. Hence, number of neutrons should be 90 - 38 = 52.</span>
Answer:
Explanation:
<u><em>What is the potential energy of a 2-kg book sitting on a shelf 2 meters above the ground?</em></u>
<em></em>
PE = MGH, that is, potential energy = mass x gravity x height.
2*2*9.8=
39.2 joules
