Answer:
Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]
Explanation:
According to Brönsted-Lowry acid-base theory:
- An acid is a substance that donates H⁺.
- A base is a substance that accepts H⁺.
When methylamine reacts with water, it behaves as a Brönsted-Lowry base, according to the following reaction.
CH₃NH₂(aq) + H₂O(l) ⇄ CH₃NH₃⁺(aq) + OH⁻(aq)
The basic equilibrium constant (Kb) is:
Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]
Answer: After three half-lives 1/8 (12.5%) of the original sample remains
The heat will flow from copper to aluminum because Cu is at higher temperature. The heat liberated is -7.60kJ
When two metals at different temperatures are kept in contact, heat flows from hotter metal to colder metal until thermal equilibrium is reached.
Here Copper is at a temperature of 60 degree Celsius and aluminum is at 40 degree Celsius. Thus, heat will flow from Cu to Al.
In order to calculate the amount of heat liberated following calculations are required.
m1=262 g
T1=87 oC
Cp=0.385 J/g oC
T2=11.8 oC
The heat liberated can be expressed as follows:
Q=mCp(T2-T1)
Q=262 g*0.385 J/goC(11.8-87)oC
Q=-7585 J
=-7.60kJ
To learn more about heat check the link below:
brainly.com/question/13439286
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