The "Dawn horses" were actually not related to horses! Recent studies of fossils found that "Dawn Horses" were buried in the same rock layers as modern horses! evolutionists were shocked at first but then decided that the "Dawn horse" was related to rabbits! Now to answer your question no one really knows why they went extinct. Evolutionist believe they changed into rabbits and Creationists (people who believe God created the universe and that evolution is incorrect) believe they died out due to climate changes after the global flood of Noah.
The best way to do this is to google search each question, or look it up on quizlet.com
Answer:
answer is 12.18
Explanation:
(C2H5NH2, Kb = 5.6 x 10-4.)
<u>Answer:</u> The amount of sample left after 20 years is 288.522 g and after 50 years is 144.26 g
<u>Explanation:</u>
We are given a function that calculates the amount of sample remaining after 't' years, which is:
Putting values in above equation:
Hence, the amount of sample left after 20 years is 288.522 g
Putting values in above equation:
Hence, the amount of sample left after 50 years is 144.26 g
Answer:
CCl4- tetrahedral bond angle 109°
PF3 - trigonal pyramidal bond angles less than 109°
OF2- Bent with bond angle much less than 109°
I3 - linear with bond angles = 180°
A molecule with two double bonds and no lone pairs - linear molecule with bond angle =180°
Explanation:
Valence shell electron-pair repulsion theory (VSEPR theory) helps us to predict the molecular shape, including bond angles around a central atom, of a molecule by examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement which tends to minimize repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom are either bonding pairs of electrons, located primarily between bonded atoms, or lone pairs. The electrostatic repulsion of these electrons is reduced when the various regions of high electron density assume positions as far apart from each other as possible.
Lone pairs and multiple bonds are known to cause more repulsion than single bonds and bond pairs. Hence the presence of lone pairs or multiple bonds tend to distort the molecular geometry geometry away from that predicted on the basis of VSEPR theory. For instance CCl4 is tetrahedral with no lone pair and four regions of electron density around the central atom. This is the expected geometry. However OF2 also has four regions of electron density but has a bent structure. The molecule has four regions of electron density but two of them are lone pairs causing more repulsion. Hence the observed bond angle is less than 109°.
