Answer:
Explanation:
In CF4 and NF3, the valence electron groups on the central C and N atoms have a tetrahedral arrangement. The shapes of the molecules are determined by the number of bonding and nonbonding of electrons: since CF4 has four bonded atom(s) and zero lone pair(s) of electrons, the shape is tetrahedral.
Answer : The final pressure will be, 666.2 mmHg
Explanation :
Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

or,

where,
= initial pressure = 790 mmHg
= final pressure = ?
= initial volume = 101.2 mL
= final volume = 120 mL
Now put all the given values in the above equation, we get:


Therefore, the final pressure will be, 666.2 mmHg
<span>The theory general relativity was discovered by Albert Einstein </span>
Compounds are elements and its a pure substance with a gised composition.
Mixtures two or more subtances mixed to together.There are 2 type of mixtures.
Homegenous Mixtures (Solutions)-Two or more substances mixed but is uniform, you cant see the different mixtures.
Ex:Sugar mixed with water.The sugar dissolves and becomes one with the water.
Heterogeneous Mixtures-Two or more substances mixed but is not uniformed.You can see all the substances put into the mixture.
Ex:A salad, you can see whats all mixed in the sald and can pick it apart.
Answer:

Explanation:
Hello,
In this case, since the Lewis theory is based on the bonds formation between atoms via the valence electrons, we can verify the chemical formula of the compound formed by strontium and nitrogen by noticing that strontium has two valence electrons as it is in group IIA, for that reason, two nitrogens should be available for bonding. Therefore, since nitrogen is in group VA, it is said that three electrons are required to attain the octet (maximum amount bonded electrons), for that reason, three strontiums are should be available for bonding. In such a way, the formula should be:

Regards.