11. What is the maximum number of electrons that an atomic orbital can contain?

1. The first four-legged animals to reach land were classified as

andrezito [222]

Explanation:

The first four-legged animals to reach land were classified as tetrapods the term tetra means four. So tetrapods refer to animals with four limbs.
Pangaea also known as Pangea was a supercontinent during the late Paleozoic and Mesozoic times. It incorporated almost the earth's land masses. The formation and breaking up of continents is a geological cyclic process. And there seemed to have many supercontinents that existed before Pangaea. And according to the sources it assembled from the earlier continental parts approximately 335 million of years ago.
Glaciation is a geographical term that explains the formation, movement, and recession of the glaciers and this process was much more evident in times when the world was covered with ice sheets. Glaciers are nothing but in simple words huge chunks of ice which gets accumulated over a period of time, whose movement is governed by its own weight. Due to this ice layers are built which keep on growing slowly together forming a thick mass of ice.
Waterbody never stops moving and this tidal movement brings a lot of changes in the environment around- flora and fauna. However, global warming causing the melting of ice and glaciers has impacted heavily on this causing the extinction of certain species.
Earlier when these environmental changes were not so rapid, marine life in terms of flora and fauna flourished underwater. There was no soil erosion, seawater contamination in terms of industrial waste being released and other contaminants causing loss of marine life.

5 0

3 years ago

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Using only the 1h nmr spectrum of the crude nitration product, determine if the product is mostly ortho-, meta-, or para- substi

tatiyna

<span>The nitartion of methyl benzoate is expected to proceed as given in the equation below:

</span>

In methyl benzoate there are 3 types of 1 H proton. The two ortho to the C=O group is a doublet at 8 ppm the 2 metal to the C=O is a multiple at 7.5 ppm and one para to the C=O is a multiplet at 7.5 ppm.

On nitration the ortho will probably show two signal one being a single with 3 proton integration and one a doublet with 1 H integration

The meta will show a highly down field singlet (coresponding to 1 proton), two unequal doublets (corresponding to 1 H each) and one multiplets (corresponding to 1H). This is the major product as seen from the 1H NMR.

The para isomer will come as two doublets which will be very close to each other there is a small signal for this set between 8.2 and 8.3 ppm.

7 0

3 years ago

Which of the following happens during a lunar eclipse?

Svetlanka [38]

Answer:

a. Earth casts a shadow on the moon.

Explanation:

Lunar eclipse occurs when Earth comes in between sun and moon. The sunlight falling on moon is blocked by Earth and the shadow of earth falls on moon. This happens on full moon day when sun, earth and moon align in one line.The moon passes through the shadow of earth and appears dark.

Thus, the correct option is a.

5 0

3 years ago

For the chemical reaction 2 HBr ( aq ) + Ba ( OH ) 2 ( aq ) ⟶ 2 H 2 O ( l ) + BaBr 2 ( aq ) 2HBr(aq)+Ba(OH)2(aq)⟶2H2O(l)+BaBr2(a

Katen [24]

Answer:

2H+ (aq) + 2OH-(aq)→ 2H2O (l)

Explanation:

Step 1: the balanced equation

2HBr(aq) + Ba(OH)2(aq) ⟶ 2H2O(l)+BaBr2(aq)

Step 2: The net ionic equation

The net ionic equation, for which spectator ions are omitted - remember that spectator ions are those ions located on both sides of the equation - will , after canceling those spectator ions in both side (Ba^2+ and Br-), look like this:

2H+ (aq) + 2OH-(aq)→ 2H2O (l)

7 0

2 years ago

To predict the products of a single replacement reaction one uses a(n) _______.

boyakko [2]

Answer:

spoon

Explanation:

7 0

2 years ago