1 mole of h3bo3...........6.023*10²³ each h and B and 0 so we will have 3hydrogen+ 1 B+3 oxygen = 7*6.023*10²³ atoms
1 mole .......7*6.023*10²³atoms
4 moles ........x atoms
x=4*7*6.023*10²³.
Answer:
Explanation:
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In this case, since the standard enthalpy change for a chemical reaction is stood for the enthalpy of reaction, for the given reaction:
We set up the enthalpy of reaction considering the enthalpy of formation of each species in the reaction at the specified phase and the stoichiometric coefficient:
In such a way, by using the NIST database, we find that:
Thus, we plug in the enthalpies of formation to obtain:
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Answer:
Answer: (b) F
Explanation:
Sodium has 1, magnesium has 2 and Aluminium has 3 electrons in its outermost shell whereas Fluorine has 7 electrons in its outermost shell hence Fluorine does not lose electrons easily.
The electronic configuration of fluorine is 2,7.
Fluorine is the ninth element with a total of 9 electrons.
The first two electrons will go in the 1s orbital.
The next 2 electrons for F go in the 2s orbital.
The remaining five electrons will go in the 2p orbital. Therefore the F electron configuration will be 1s22s22p5.
I think its A because some scientist from the Department of Physics of Northeastern University found out that is not a part of Dalton's atomic theory.
Answer:
1)The molar mass of an atom is simply the mass of one mole of identical atoms. However, most of the chemical elements are found on earth not as one isotope but as a mixture of isotopes, so the atoms of one element do not all have the same mass.
2)Equally important is the fact that one mole of a substance has a mass in grams numerically equal to the formula weight of that substance. Thus, one mole of an element has a mass in grams equal to the atomic weight of that element and contains 6.02 X 1023 atoms of the element.
