4.1 h = 14760 s
<span>t 1/2 = ln 2 / k </span>
<span>k = rate reaction = 4.97 x 10^-5 </span>
<span>ln 0.045 / 0.36 = - 4.97 x 10^-5 t </span>
<span>2.08 = 4.97 x 10^-5 t </span>
<span>t = 41839.9 s = 11 h 37 min 19 s</span>
Answer: 1.414x10^24 molecules in 94.4g MgO
Explanation: molar mass MgO 40.204
molecules in 40.204 g MgO = avogadro number
molecules in 94.4 g MgO = (94.4/40.204)*avogadro number
(94.4/40.204)*6.02214076*10^23 = 14.14x10^23
Answer:
0.0457 M
Explanation:
The reaction that takes place is:
- 2HBr + Ca(OH)₂ → CaBr₂ + 2H₂O
First we<u> calculate how many moles of acid reacted</u>, using the <em>HBr solution's concentration and volume</em>:
- Molarity = Moles / Volume
- Molarity * Volume = Moles
- 0.112 M * 12.4 mL = 1.389 mmol HBr
Now we <u>convert HBr moles to Ca(OH)₂ moles</u>, using the stoichiometric ratio:
- 1.389 mmol HBr *
= 0.6944 mmol Ca(OH)₂
Finally we <u>calculate the molarity of the Ca(OH)₂ solution</u>, using the <em>given volume and calculated moles</em>:
- 0.6944 mmol Ca(OH)₂ / 15.2 mL = 0.0457 M
The elements that apply are argon, neon and helium. These elements are called inert gasses and have unique properties that make them unreactive. These elements are so unreactive that they are classified as chemically inert.
The elements belong to a group in the periodic table known as the Noble Gases. They belong to family 18 of the periodic table and have atoms with 8 valence electrons. This configuration causes the gases to be unreactive.
