The average atomic mass of element X is 14.007 u.
The average atomic mass of X is the <em>weighted average</em> of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its <em>relative importance</em> (i.e., its % abundance).
Thus,
0.996 36 × 14.003 u =13.952 03 u
0.003 64 × 15.000 u = <u>0.054 60 u</u>
__________TOTAL = 14.007 u
We are given that 1 teaspoon is equivalent to 5 mL,
therefore 0.75 teaspoon is:
0.75 teaspoon * (5 mL / 1 teaspoon) = 3.75 mL
So the mass is density times volume:
mass = (12.5 mg/5 ml) * 3.75 mL
<span>mass = 9.375 mg</span>
Answer:
4.42x10⁻¹⁹ J/molecule
Explanation:
At a double bond, there's sigma and a pi bond, and at a single bond, there's only a sigma bond. Thus, if the energy to break both sigma and pi is 614 kJ/mol, and the energy to break only the sigma bond is 348 kJ/mol, the energy to break only the pi bond is:
E = 614 - 348 = 266 kJ/mol
Knowing that 1 kJ = 1000 J, E = 266,000 J/mol
By Avogadro's number, 1 mol = 6.02x10²³ molecules, thus:
E = 266,000 J/mol * 1mol/6.02x10²³ molecules
E = 4.42x10⁻¹⁹ J/molecule
Answer:
See explanation
Explanation:
According to the Bohr model of the atom, electrons are found in energy levels. Energy is absorbed or emitted when an electron moves from one energy level to another.
During flame test, electrons absorb energy and move to higher energy levels; they quickly return to ground state and emit the energy previously absorbed as a photon of light. This is seen as the colour imparted to the flame by the metal.
The emission spectrum tells us about the range of wavelengths emitted by an atom or compound when it is excited. At an atomic level, the electrons are moved to higher energy levels and as they return to ground state, they emit the various wavelengths that comprise the emission spectrum of any particular substance.
Answer
Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.
