Answer:
Photon of light
Explanation:
According to Bohr's model of the atom, electrons in atoms are found in specific energy levels. These energy levels are called stationary states, an electrons does not radiate energy when it occupies any of these stationary states.
However, an electron may absorb energy and move from one energy level or stationary state to another. The energy difference between the two energy levels must correspond to the energy of the photon of light absorbed in order to make the transition possible.
Since electrons are generally unstable in excited states, the electron quickly jumps back to ground states and emits the excess energy absorbed. The frequency or wavelength of the emitted photon can now be measured and used to characterize the transition. This is the principle behind many spectrometric and spectrophotometric methods.
all the elements in group 18 are Nobel gases or inert gases . all the elements such as neon , helium, argon etc. ,their outermost shell is completely filled . The noble gases have the largest ionization energies, reflecting their chemical inertness
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Answer:
A. to determine the efficiency of the reaction
Explanation:
- Percentage is the ratio of the actual yield to theoretical yield as a percentage. It is calculated by dividing the actual yield by theoretical yield then multiplying by 100%.
- Calculation of percentage yield is important as it helps in the determination of efficiency of a reaction. For example in most industries for the purpose of making the most product with the least waste.
- Additionally, calculating the percentage yield helps in determining other products that may be formed during the reactions.
Answer:
58.0 g/mol
Explanation:
The reaction that takes place is:
- MCl₂ + 2AgNO₃ → 2AgCl + M(NO₃)₂
First we <u>calculate how many moles of silver chloride</u> were produced, using its <em>molar mass</em>:
- 6.41 g AgCl ÷ 143.32 g/mol = 0.0447 mol AgCl
Then we <u>convert AgCl moles into MCl₂ moles</u>, using the <em>stoichiometric ratio</em>:
- 0.0447 mol AgCl *
= 0.0224 mol MCl₂
Now we<u> calculate the molar mass of MCl₂</u>, using the original<em> mass of the sample</em>:
- 2.86 g / 0.0224 mol = 127.68 g/mol
We can write the molar mass of MCl₂ as:
- Molar Mass MCl₂ = Molar Mass of M + (Molar Mass of Cl)*2
- 127.68 g/mol = Molar Mass of M + (35.45 g/mol)*2
Finally we<u> calculate the molar mass</u> of M:
- Molar Mass of M = 57 g/mol
The closest option is 58.0 g/mol.
