Answer:
Four electrons are present in the valence shell of Silicon.
Explanation:
Valence shell electrons are those electrons which are present in the outermost shell of an atom. These valence shell electrons are responsible for in the formation of bonds with other atoms.
Silicon having atomic number 14 has fourteen electrons in its neutral state and has the electronic configuration as follow;
1s², 2s², 2p⁶, 3s², 3p²
In given configuration the valence shell (outermost shell) is 3 and the number of electrons present in it are four i.e. 3s² and 3p² (2 + 2 = 4) respectively.
Answer:
True => ΔH°f for C₆H₆ = 49 Kj/mole
Explanation:
See Thermodynamic Properties Table in appendix of most college level general chemistry texts. The values shown are for the standard heat of formation of substances at 25°C. The Standard Heat of Formation of a substance - by definition - is the amount of heat energy gained or lost on formation of the substance from its basic elements in their standard state. C₆H₆(l) is formed from Carbon and Hydrogen in their basic standard states. All elements in their basic standard states have ΔH°f values equal to zero Kj/mole.
The maximum height at which nitrogen molecule will go before coming to rest is 14 kilometers.
Given:
The nitrogen gas molecule with a temperature of 330 Kelvins is released from Earth's surface to travel upward.
To find:
The maximum height of a nitrogen molecule when released from the Earth's surface before coming to rest.
Solution:
- The maximum height attained by nitrogen gas molecule = h
- The temperature of nitrogen gas particle = T = 330 K
The average kinetic energy of the gas particles is given by:

The nitrogen molecule at its maximum height will have zero kinetic energy as all the kinetic energy will get converted into potential energy
- The potential energy at height h =

- Molar mass of nitrogen gas = 28.0134 g/mol
- Mass of nitrogen gas molecule = m

- The acceleration due to gravity = g = 9.8 m/s^2
- The maximum height attained by nitrogen gas molecule = h
- The potential energy is given by:


The maximum height at which nitrogen molecule will go before coming to rest is 14 kilometers.
Learn more about the average kinetic energy of gas particles here:
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Answer:
The amount/type of stain
Explanation:
You would want to ensure that the stain was the same in both samples.