Answer:
NH₃
Explanation:
The compound that is covalent from the given choices is NH₃.
Covalent compounds are usually formed between two atoms with similar values of electronegativities such that the difference is very small or zero.
- This bond type involves the sharing of electrons between two atoms with similar electronegativities.
- Nitrogen and hydrogen forms stable configuration that are isoelectronic with noble gases by sharing their valence electrons.
- The 3 hydrogen electrons are enough to make nitrogen isoelectronic with neon.
- Also, the nitrogen with 3 lone pairs of electrons provides the bonding hydrogen with needed electrons to attain a structure similar to helium.
The speed of sound at T=25°C is Vs=346 m/s. So the sound has to reach the cliff and return back to you so the path it needs to travel is s=2*440 m = 880 m.
Since the speed of sound is constant s=Vs*t, and t= s/Vs=880/346=2.54335 s. You will hear the echo after t=2.54335 s after you shouted.
Answer: The area of brick in contact with the floor is 1539 
.
Explanation:
Given: Length = 19 cm
Width = 9 cm
Height = 9 cm
As the brick is rectangular in shape. Hence, its area will be calculated as follows.
Substitute the values into above formula as follows.
Thus, we can conclude that area of brick in contact with the floor is 1539 .
<span>The repelling of the support magnet decreases friction. is the answer you're looking for . :)
hope i helped - beanz</span>
