If you follow the octet rule, you know that an element must have 8 outside (or valence) electrons to be energetically favorable.
In CCl4, the carbon molecule forms four bonds; one for each chlorine atom. Each bond contains 2 electrons, so it is satisfied.
In PCl3, Phosphorous forms only 3 bonds with chlorine, which means in order to have 8 valence electrons, it also has a lone pair of electrons, not bonded with chlorine.
Now, in CCl4, picture the shape of the molecule like a plus sign, with the carbon in the middle and the chlorine at the four ends. It is symmetrical, and therefore is nonpolar.
In PCl3, the lone pair electrons <em>push</em>, so to speak, the 3 chlorine atoms away, making a T-shaped molecule. Since the chlorine is more electronegative than carbon, the molecule is unbalenced, making it polar.
Answer:
D. The coefficients give the ratio of mole reactant to moles product.
Explanation:
In stoichiometric calculations, the amount of product formed from reactants can be determined.
- Using this approach, the number of moles of reactants and products on both sides of the expression must be balanced.
- As a rule of thumb, the coefficients give the ratio of moles of reactants to moles of products.
- This is very useful in a number of calculations using the stoichiometric approach.
Answer:
the mas is .291 g
Explanation:
the mass of a object does not change. so when added the substance the beaker. you had the mass of both objects together. you know the mass of the beaker and you know the mass of both. since mass does not change. the beakers mass is still 74.605g. the mass of both objects is 74.896. all you have to do is subtract the mass of the beaker from the total mass. 74.896 - 74.605 equals .291g. so the mass of the unknown substance Is .291g
