From,
RAM=element×its relative abudance/total abudance
=((107×13)+(12×109))/25
The answer is=107.96
The chalk particles embed themselves into the small pores on the surface.
Although a chalkboard seems smooth to the touch, it is quite rough at the microscopic level, with <em>pores</em> that reach below the surface.
When you drag chalk across the board, friction causes small particles of chalk to rub off onto the surface.
If you leave the markings for a long time, some of the chalk particles will work their way into the pores.
A brush will remove the surface particles, but <em>it will not be able to get at the particles in the pores</em>.
I believe that it most likely would be D.
Answer:
Water has a higher boiling point because the hydrogen bonds that form water molecules are stronger than the Van der Waals interactions among methane molecules, therefor more energy must be provided in order to break the hydrogen bonds and allow the water molecules to escape the liquid state.
Explanation:
Answer:
the equilibrium constant is 1.8 x 10⁻5 and strongly favor the reactants.
Explanation:
the chemical reaction provided for the two equation are the same but different direction i.e a reversible reaction. Assuming, the mass of reactants and product and temperature remain constant.
therefore, the equilibrium constant K, is 1.8 x 10⁻5. this is a very small value of K, thereby strongly favor the backward direction to form reactant.
