Answer:
B). Allow efficient gathering of unobservable phenomena.
Explanation:
Surveys are described as the method of gathering information from a specified group of respondents for purposes like research or assessment of the truth of thoughts or opinions associated with a process.
As per the question, one of the most considerable benefits of the survey is that 'it allows the efficient gathering of unobservable phenomena'. The data associated with phenomena like stated preferences, behaviors, beliefs, and factual information are unobservable and can not be collected through observation but surveys help in doing so as well as in the assessment of the validity or reliability of the existing propositions about such phenomena. Thus, <u>option B</u> is the correct answer.
Answer:
Mass = 8 g
Explanation:
Given data:
Mass of MgO formed = 20 g
Mass of oxygen needed = ?
Solution:
Chemical equation:
2Mg + O₂ → 2MgO
Number of moles of MgO:
Number of moles = mass/molar mass
Number of moles = 20 g/ 40 g/mol
Number of moles = 0.5 mol
Now we will compare the moles of MgO and O₂ from balance chemical equation:
MgO : O₂
2 : 1
0.5 : 1/2×0.5 = 0.25 mol
Mass of oxygen required:
Mass = number of moles × molar mass
Molar mass of O₂ is 32 g/mol
Mass = 0.25 mol × 32 g/mol
Mass = 8 g
Answer:
(<em>n</em> = 7) ⟶ (<em>n</em> = 4)
Explanation:
1. Convert the energy to <em>joules per mole of electrons</em>.
<em>E</em> = 55.1 × 1000 = 55 100 J/mol
2. Convert the energy to <em>joules per electron
</em>
<em>E</em> = 55 100/(6.022 × 10²³)
<em>E</em> = 9.150 × 10⁻²⁰ J/electron
3. Use the Rydberg equation to <em>calculate the transition
</em>
Rydberg's original formula was in terms of wavelengths, but we can rewrite it to have the units of energy. The formula then becomes
where
= the Rydberg constant = 2.178 × 10⁻¹⁸ J
and 
are the initial and final energy levels.
