A COVALENT BOND, FORMS BETWEEN ELEMENTS WITH SIMILAR ELECTRONEGATIVITY AS SHARING OF ELECTRON PAIRS BETWEEN ATOMS IS EASIER AS THEY ARE IDENTICAL.
Explanation:
Bonding atoms with similar electronegativity values form covalent bonds.
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
Covalent bonds form between two nonmetal atoms with identical or relatively close electronegativity values
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons, also it is the strength an atom has to attract a bonding pair of electrons to itself.
Pure covalent bonds result when two atoms of the same electronegativity bond. This occurs only when two atoms of the same element bond with each other.
Hydrogen gas(H2) has a molar mass of 2 g. Molar mass of a substance is defined as the mass of 1 mole of that substance. And by 1 mole it is meant a collection of 6.022*10^23 particles of that substance.
So number of moles of H2 are 0.5 in this case. And thus it means there are (6.022*10^23)*0.5 particles( here they are molecules) in 1g of H2.
Answer:
The correct option is C
Explanation:
From the question we are told that
The reaction is
Generally 
Here 
is the change in enthalpy
is the change in the internal energy
is the difference between that number of moles of product and the number of moles of reactant
Looking at the reaction we can discover that the elements that was consumed and the element that was formed is 
and 
and this are both gases so the change would occur in the number of moles
So
![\Delta H = \Delta U + [16 -23]* RT](https://tex.z-dn.net/?f=%5CDelta%20%20H%20%20%3D%20%20%5CDelta%20%20U%20%2B%20%5B16%20-23%5D%2A%20%20RT)
The negative sign in the equation tell us that the enthalpy
would be less than the Internal energy 
Answer: It will take 3 days for half of a 10 g sample to decay.
Explanation:
Half-life of sample of an isotope X = 3 days
Sample decayed = 
N=
, time = t
![\ln[5 g]=-0.231 day^{-1}\times t\ln[10]](https://tex.z-dn.net/?f=%5Cln%5B5%20g%5D%3D-0.231%20day%5E%7B-1%7D%5Ctimes%20t%5Cln%5B10%5D)
![\ln[\frac{5}{10}]=-0.231\times t](https://tex.z-dn.net/?f=%5Cln%5B%5Cfrac%7B5%7D%7B10%7D%5D%3D-0.231%5Ctimes%20t)
t = 3 days
It will take 3 days for half of a 10 g sample to decay.
