Which of the following situations contains an example of a chemical reaction?
1 answer:
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Answer:
178.98 sq. feet
Explanation:
The path and the garden has been shown in the figure below. The green area is the garden and the area in brown is the path.
It has been given that,
Radius of garden = 8 feet
So, the area of garden = 3.14 × 8 × 8 = 200.96 sq. feet
The total radius of the land including garden and path = 8 + 3 = 11 feet
So, the total are of land including garden and path = 3.14 × 11 × 11 = 379.94 sq. feet
So, the area of path = Total area of the land - area of garden
Area of path = 379.94 - 200.96 = 178.98 sq. feet
Answer:
1) After adding 15.0 mL of the HCl solution, the mixture is before the equivalence point on the titration curve.
2) The pH of the solution after adding HCl is 12.6
Explanation:
10.0 mL of 0.25 M NaOH(aq) react with 15.0 mL of 0.10 M HCl(aq). Let's calculate the moles of each reactant.
There is an excess of NaOH so the mixture is before the equivalence point. When HCl completely reacts, we can calculate the moles in excess of NaOH.
NaOH + HCl ⇒ NaCl + H₂O
Initial 2.5 × 10⁻³ 1.5 × 10⁻³ 0 0
Reaction -1.5 × 10⁻³ -1.5 × 10⁻³ 1.5 × 10⁻³ 1.5 × 10⁻³
Final 1.0 × 10⁻³ 0 1.5 × 10⁻³ 1.5 × 10⁻³
The concentration of NaOH is:
NaOH is a strong base so [OH⁻] = [NaOH].
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log 0.040 = 1.4
pH = 14 - pOH = 14 - 1.4 = 12.6