<u>Answer:</u>
Exothermic Reaction are those reaction, in which energy is released while in endothermic reaction are those, in which energy is absorbed.
<u>Explanation:</u>
First Reaction:
As in this reaction, energy is released
½H2(g) + ½I2(g) → HI(g), ΔH = +6.2 kcal/mole
so it is <em>exothermic reaction</em>
Second reaction:
As in this reaction, energy is absorbed
21.0 kcal/mole + C(s) + 2S(s) → CS2(l)
so it is <em>endothermic reactions</em>.
Answer:
4. Atmospheric pressure decreases as altitude increases.
Explanation:
hope this helps and is right. p.s i really need brainliest :)
As it dissolves a large number of solid, liquid and gaseous substances it's called a universal solvent. It's important for living thing because all of them depend on water to survive. For example, many organisms live in the water and they find some of the nutrients that are necessary for live dissolved in water - gases included.
Answer:

Explanation:
To solve this problem, we can use the Combined Gas Laws:

Data:
p₁ = 1.7 kPa; V₁ = 7.5 m³; T₁ = -10 °C
p₂ = ?; V₂ = 3.8 m³; T₂ = 200 K
Calculations:
(a) Convert temperature to kelvins
T₁ = (-10 + 273.15) K = 263.15 K
(b) Calculate the pressure

They have the same number of electrons in their outer shells. Elements in the same group often share similar chemical properties because the outer electrons generally determine a lot of their properties