To determine the amount of heat needed to evaporate a certain amount of water at its boiling point, we use the equation,
H = m(Hv)
where H is the heat, m is the mass (in grams), and Hv is the latent heat of vaporization. Substituting the known values,
H = (105 g)(540 cal/g)
H = 56700 cal
H = 56.7 kcal
Answer: 56.7 kcal
Answer:
The sun is a star but It is the brightest in the sky because it is the closest star to earth.
I don't know how to compare it to street lights though...
Explanation:
Answer:
4.9 × 10²³ molecules
Explanation:
Given data:
Number of molecules = ?
Number of moles of oxygen = 0.815 mol
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules
0.815 mol × 6.022 × 10²³ molecules / 1 mol
4.9 × 10²³ molecules
The top number on elements in the periodic table is the atomic number, so when you look at the periodic table you can see that 42 is Mo (Molybdenum), and this is the only element with that atomic number.
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