Answer:
negative
Explanation:
Entropy is a measure of the "disorder" in a system.
In this reaction, the amount of disorder decreases. This is because one gas molecule (NH₃) has more order than two gas molecules (N₂ and H₂). Therefore, the entropy change should be negative.
Answer:
Carbon, germanium, tin and lead.
Explanation:
The silicon is belong to the carbon family. There are five elements in carbon family carbon, silicon, germanium, tin and lead. These five elements are present in same group i.e group fourteen. The elements present in same group have same number of valance electrons.
For example.
Carbon electronic configuration:
C₆ = [He] 2s² 2p²
Silicon electronic configuration:
Si₁₄ = [Ne] 3s² 3p²
Germanium electronic configuration:
Ge₃₂ = [Ar] 3d¹⁰ 4s² 4p²
Tin electronic configuration:
Sn₅₀ = [Kr] 4d¹⁰ 5s² 5p²
Lead electronic configuration:
Pb₈₂ = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p²
we can see that in case of all elements there are four valance electrons, which are equal to the valance electrons of silicon.
Sound travels in waves and the height of the wave is the loudness of the sound.
To decrease sound, you need to make the waves not so high, so you can
- decrease the amplitude
- decrease the height of the crest (lower the top of the wave down)
- increase the height of the trough (bring the bottom of the wave up)
It's all about getting the wave to be closer to the center, to not be so high and low, but to be flatter.
(picture taken from sound . eduation website)
The tall trees much of the sun
have you ever been in a forest? if you have, you’ve probably noticed that it’s usually very shady, and not a lot of sunlight hits the ground. That’s cause the tall trees are so dense, the sunlight doesn’t reach the ground
During summer, the Earth's orbit brings Australia closer to the sun (as compared to Europe during its summer), resulting in an additional 7% solar UV intensity. Coupled with our clearer atmospheric conditions, this means that Australians are exposed to up to 15% more UV than Europeans.
