Answer:
Kₐ = 6.7 x 10⁻⁴
Explanation:
First lets write the equilibrium expression, Ka , for the dissociation of hydrofluoric acid:
HF + H₂O ⇄ H₃O⁺ + F⁻
Kₐ = [ H₃O⁺ ] [ F⁻ ] /[ [ HF ]
Since we are given the pH we can calculate the [ H₃O⁺ ] ( pH = - log [ H₃O⁺ ] , and because the acid dissociates into a 1: 1 relation , we will also have [F⁻ ]. The [ HF ] is given in the question so we have all the information that is needed to compute Kₐ.
pH = -log [ H₃O⁺ ]
1.68 = - log [ H₃O⁺ ]
Taking antilog to both sides of this equation:
10^-1.68 = [ H₃O⁺ ] ⇒ 2.1 X 10⁻² M= [ H₃O⁺ ]
[ F⁻ ] = 2.1 X 10⁻² M
Solving for Kₐ :
Kₐ = ( 2.1 X 10⁻² ) x ( 2.1 X 10⁻² ) / 0.65 = 6.7 x 10⁻⁴
(Rounded to two significant figures, the powers of 10 have infinite precision )
Heterotrophic cells must ingest biomass to obtain their energy and nutrition. Heterotrophic microorganisms mostly feed upon dead plants and animals, and are known as decomposers. ... Some animals also specialize on feeding on dead organic matter, and are known as scavengers or detritivores. Hope this was helpful.
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Temperature, cloud cover and thunder are all examples of weather.
<h3><u>Explanation:</u></h3>
Weather is described as conditions that prevail for a short period of time and the above-mentioned factors change variably throughout the day. Cloud cover simply describes the clouds coverage in the sky. It is one factor that is used to describe weather conditions since the type of clouds indicates prevailing weather.
For example, the presence of cirrus means there will be a storm in 24 to 48 hours. Weather conditions characterized by thunder is said to be stormy and it also has other conditions such as lightning, wind and fast rain with heavy raindrops. Temperature affects the warmness and coldness of the air and its movement. Moreover, it also affects all other aspects of weather conditions.
