Answer is: ph value is 3.56.
Chemical reaction 1: H₂CO₃(aq) ⇄ HCO₃⁻(aq) + H⁺(aq); Ka₁ = 4,3·10⁻⁷.
Chemical reaction 2: HCO₃⁻(aq) ⇄ CO₃²⁻(aq) + H⁺(aq); Ka₂ = 5,6·10⁻¹¹.
c(H₂CO₃) = 0,18 M.
[HCO₃⁻] = [H⁺<span>] = x.
</span>[H₂CO₃] = 0,18 M - x.
Ka₁ = [HCO₃⁻] · [H⁺] / [H₂CO₃].
4,3·10⁻⁷ = x² / (0,18 M -x).
Solve quadratic equation: x = [H⁺] =0,000293 M.
pH = -log[H⁺] = -log(0,000293 M).
pH = 3,56; second Ka do not contributes pH value a lot.
<u>The addtion of energy</u> <span>is usually needed to help a decomposition reaction occur</span>
It takes 0.26 minutes to travel 1000 feet
<u>Solution:</u>
Given that car traveling at a constant speed travels 175 miles in four hours
Distance = 175 miles
Time taken = 4 hours
Convert the units to feet and minute
Given that,
1 mile = 5280 feet
175 miles = 5280 x 175 feet = 918720 feet
Also we know that,
1 hour = 60 minutes
4 hours = 60 x 4 minutes = 240 minutes
Thus, we got,
Distance = 918720 feet
Time taken = 240 minutes
<em><u>Find the speed of car</u></em>
<em><u>Speed is given by formula:</u></em>


Thus speed of car is 3828 feet per minute
<em><u>How many minutes will it take for the car to travel 1000 feet?</u></em>
Let "x" be the minutes needed for 1000 feet
speed of car is 3828 feet per minute
1 minute = 3828 feet
x minute = 1000 feet
This forms a proportion. We can solve by cross multiplying

Thus it takes 0.26 minutes to travel 1000 feet