Answer:
H2O> NH3> CH4
Explanation:
According to valence shell electron pair repulsion theory (VSEPR), bond angles and repulsion of electron pairs depends on the nature of electron pairs on the central atom of the molecule. Lone pairs cause more repulsion (and distortion of bond angles) than bond pairs). Lone pair- lone pair repulsion is greater than lone pair bond pair repulsion.
Water contains two lone pairs on oxygen hence it experiences the greatest repulsion. Ammonia has only one lone pair on nitrogen hence there is lesser repulsion between lone pairs and bond pairs. Methane possess only bond pairs of electrons hence it has the least repulsion.
Answer: A “system in exchange of matter with its environment, presenting import and export, building-up and breaking-down of its material components.”
Explanation:
In chemistry:
The <u>molar mass</u> is the mass of a chemical element or compound divided by the amount of substance in the element.
That table salt has a high melting point and mercury's melting point is low.
Answer:
1.51 x 10²⁴molecules
Explanation:
Given parameters:
Number of moles of NaCl = 2.5moles
Unknown:
Number of molecules = ?
Solution:
The number of molecules that can be found in a given mole is given as the Avogadro's constant;
1 mole of substance = 6.02 x 10²³ molecules
2.5 mole of NaCl = 2.5 x 6.02 x 10²³ molecules
= 1.51 x 10²⁴molecules
