An endothermic chemical reactions products tend to have a higher potential energy than the reactants. Thus making the /\ H positive, not negative.
Answer:
At -13
, the gas would occupy 1.30L at 210.0 kPa.
Explanation:
Let's assume the gas behaves ideally.
As amount of gas remains constant in both state therefore in accordance with combined gas law for an ideal gas-

where
and
are initial and final pressure respectively.
and
are initial and final volume respectively.
and
are initial and final temperature in kelvin scale respectively.
Here
,
,
,
and
Hence 



So at -13
, the gas would occupy 1.30L at 210.0 kPa.
1) START counting for sig. figs. On the FIRST non-zero digit.
2) STOP counting for sig. figs. On the LAST non-zero digit.
3) Non-zero digits are ALWAYS significant.
4) Zeroes in between two non-zero digits are significant. All other zeroes are insignificant.
Answer:
It is getting thicker and keeping the Earth warmer.
1)False
2)Meters allow scientists to be more accurate.
3)Air resistance.
4)C
5)Two stars very close together.
6)Rolling Friction
7)A elevator coming to a stop in order to stop at the top floor.
8)Size of the ofject