Answer:
(A) 28
Explanation:
To solve this problem we use the <em>PV=nRT equation</em>, where:
- P = 800 mmHg ⇒ 800/760 = 1.05 atm
- R = 0.082 atm·L·mol⁻¹·K⁻¹
- T = 25.0 °C ⇒ 25.0 + 273.16 = 298.16 K
We<u> input the data</u>:
- 1.05 atm * 2.00 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K
And <u>solve for n</u>:
Now we calculate the gas' mass:
- Gas Mass = (Mass of Container w/ Gas) - (Mass of Empty Container)
- Gas Mass = 1052.4 g - 1050.0 g = 2.4 g
Finally we <u>calculate the unknown gas' molar mas</u>s, using<em> its mass and its number of moles</em>:
- Molar Mass = mass / moles
- Molar Mass = 2.4 g / 0.086 mol = 27.9 g/mol
So the answer is option (A).
its exothermic. exothermic means the reaction gives out heat. [exo meaning outside and thermic meaning heat] because its a combustion reaction, fire is there meaning lots of heat.
endothermic means it takes in heat. a good example is ammonium and water (NH3 +H20)
<span>most chemical reaction are exothermic</span>
