Answer:A) cotton
A fiber if available in trace or appropriate amount can link a suspect to a crime.Solubility is a preliminary test performed for identification of the type of fiber. In this method small amount of fiber evidence is dissolved in the suitable solvent to identify it's type. Some fibers completely get solublize in the solvent, some get partially soluble and other can only change their color or do not dissolve at all.
According to the given situation, the fiber dissolved in hydrochloric acid can be cotton. As the fibers of cotton are soft and slender and will get easily solubilize in hydrochloric acid.
The volume of the 0.279 M Ca(OH)₂ solution required to neutralize 24.5 mL of 0.390 M H₃PO₄ is 51.4 mL
<h3>Balanced equation </h3>
2H₃PO₄ + 3Ca(OH)₂ —> Ca₃(PO₄)₂ + 6H₂O
From the balanced equation above,
- The mole ratio of the acid, H₃PO₄ (nA) = 2
- The mole ratio of the base, Ca(OH)₂ (nB) = 3
<h3>How to determine the volume of Ca(OH)₂ </h3>
- Molarity of acid, H₃PO₄ (Ma) = 0.390 M
- Volume of acid, H₃PO₄ (Va) = 24.5 mL
- Molarity of base, Ca(OH)₂ (Mb) = 0.279 M
- Volume of base, Ca(OH)₂ (Vb) =?
MaVa / MbVb = nA / nB
(0.39 × 24.5) / (0.279 × Vb) = 2/3
9.555 / (0.279 × Vb) = 2/3
Cross multiply
2 × 0.279 × Vb = 9.555 × 3
0.558 × Vb = 28.665
Divide both side by 0.558
Vb = 28.665 / 0.558
Vb = 51.4 mL
Thus, the volume of the Ca(OH)₂ solution needed is 51.4 mL
Learn more about titration:
brainly.com/question/14356286
<h3>
Answer: Choice A) 0-7</h3>
Explanation:
If the pH is between 0 and 7, then we have an acid.
If the pH is between 7 and 14, then we have an alkaline base.
If pH = 7, then it's neutral.
<span>The number of neutrons bromine will have are equal to
= protons + neutrons
so,
80-35=45</span>
Well, figures for efficiency vary a lot, but according to Bicycling Science it’s lubrication that matters most – lubing a dry chain can add 5% to the efficiency.
More interestingly (and I hadn’t read this bit in the book before) it varys a lot depending on gear ratio – bottom gear (22-28) is 99% efficient, top gear (42-11) is 88%. That’s a big difference