Answer:
<em>If the Universe holds enough matter, including dark matter, the combined gravitational attraction of everything will gradually halt this expansion and precipitate the ultimate collapse. Over time, galaxies, then individual stars, will smash into each other more frequently, killing off any life on nearby planets.</em>
Some social patterns are helpful, while others are harmful.
The waxing crescent moon I believe
The distance from one crest to the next crest in a set of waves is called the wavelength. The distance from the crest of one wave to the equilibrium point is called frequency.
Hope that helped! =)
To find the temperature it is necessary to use the expression and concepts related to the ideal gas law.
Mathematically it can be defined as

Where
P = Pressure
V = Volume
n = Number of moles
R = Gas constant
T = Temperature
When the number of moles and volume is constant then the expression can be written as

Or in practical terms for this exercise depending on the final temperature:

Our values are given as

Replacing

Therefore the final temperature of the gas is 800K