If a disease strikes the snake population in the food chain shown, what will happen to the populations of hawks?
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Answer: 2.7 grams
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Given: mass of sodium hydrogen carbonate = 3.4 g
mass of acetic acid = 10.9 g
Mass of reactants = mass of sodium hydrogen carbonate+ mass of acetic acid = 3.4 + 10.9= 14.3 g
Mass of reactants = Mass of products in reaction vessel + mass of carbon dioxide (as it escapes)
Mass of carbon dioxide = 14.3 - 11.6 =2.7 g
Thus the mass of carbon dioxide released during the reaction is 2.7 grams.
Answer:
a. The pH of a sample of lemon juice with [H⁺] = 3.8*10⁻⁴ M is 3.4, indicating acidity.
b. The pH of a commonly available window-cleaning solution with [OH⁻] = 1.9*10⁻⁶ M is 8.28, indicating basicity.
c. The [H⁺] is 1.74*10⁻⁴ M.
d. The [OH⁻] is 1.51*10⁻⁵ M.
Explanation:
pH is a measure of acidity or alkalinity that indicates the amount of hydrogen [H⁺] or hydronium [H₃O⁺] ions present in a solution or substance. Mathematically the pH is the negative logarithm of the molar concentration of the hydrogen or proton ions (H⁺) or hydronium ions (H₃O⁺):
pH= -log₁₀ [H⁺]= -log₁₀ [H₃O⁺] or pH= -log [H⁺]= -log [H₃O⁺]
The pH scale ranges from 0 to 14. Values less than 7 indicate the acidity range and those greater than 7 indicate alkalinity or basicity. Value 7 is considered neutral.
<u><em>Case a</em></u>
You know [H⁺]= 3.8*10⁻⁴ M. Then:
pH= -log (3.8*10⁻⁴)
pH=3.42
<em>The pH of a sample of lemon juice with [H⁺] = 3.8*10⁻⁴ M is 3.4, indicating acidity.</em>
<u><em>Case b</em></u>
Like pH, pOH (or OH potential) is a measure of the basicity or alkalinity of a solution.
The pOH indicates the concentration of hydroxyl ions [OH-] present in a solution:
pOH= -log₁₀ [OH⁻]= -log [OH⁻]
The pOH is related to the pH by the formula:
pH + pOH= 14
In this case you know [OH⁻]=1.9*10⁻⁶ M. Then:
pOH= -log(1.9*10⁻⁶)= 5.72
So pH + 5.72= 14
pH= 14 - 5.72
pH= 8.28
<em>The pH of a commonly available window-cleaning solution with [OH⁻] = 1.9*10⁻⁶ M is 8.28, indicating basicity.</em>
<u><em>Case c</em></u>
You know pH=3.76. Then:
3.76= -log [H⁺]
-3.76= log [H⁺]
[H⁺]=
[H⁺]= 1.74*10⁻⁴ M
<em>The [H⁺] is 1.74*10⁻⁴ M.</em>
<u><em>Case d</em></u>
You know that pH + pOH=14 and pH is 9.18. Then
9.18 + pOH=14
pOH=14 - 9.18
pOH= 4.82
You know pOH= - log [OH⁻]. Then:
4.82= -log [OH⁻]
-4.82= log [OH⁻]
[OH⁻]=
[OH⁻]= 1.51*10⁻⁵ M
<em>The [OH⁻] is 1.51*10⁻⁵ M.</em>