Answer:
Small holes in plants that allow carbon dioxide in and oxygen and water vapor out
Explanation:
Stomata are tiny holes that open and close for the plant to breathe.
The ph of the best buffer is 4.74
The given acetic acid is a weak acid
The equation of the pH of the buffer
pH = pKa + log ( conjugate base / weak acid ).
For best buffer the concentration of the weak acid and its conjugate base is equal.
pH = pKa + log 1
pH = pKa + 0
pH = pKa
given Ka = 1.8 × 10⁻⁵
pKa = - log ka
pH = -log ( 1.8 × 10⁻⁵ )
pH = 4. 74
Hence the pH of the best buffer is 4.74
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Answer:
Nucleic acid is an important class of macromolecules found in all cells and viruses. Deoxyribonucleic acid (DNA) encodes the information the cell needs to make proteins.
A related type of nucleic acid, called ribonucleic acid (RNA), comes in different molecular forms that participate in protein synthesis.
Answer:
No
Explanation:
One mole of P₄ react with six moles of I₂ and gives 4 moles of PI₃.
When one gram phosphorus and 6 gram of iodine react they gives 8.234 g
ram of PI₃ .
Given data:
Mass of phosphorus = 1 g
Mass of iodine = 6 g
Mass of PI₃ = ?
Solution:
Chemical equation:
P₄ + 6I₂ → 4PI₃
Number of moles of P₄:
Number of moles = Mass /molar mass
Number of mole = 1 g / 123.9 g/mol
Number of moles = 0.01 mol
Number of moles of I₂:
Number of moles = Mass /molar mass
Number of moles = 6 g / 253.8 g/mol
Number of moles = 0.024 mol
Now we will compare the moles of PI₃ with I₂ and P₄.
I₂ : PI₃
6 : 4
0.024 :
4/6×0.024 = 0.02
P₄ : PI₃
1 : 4
0.01 : 4 × 0.01 = 0.04 mol
The number of moles of PI₃ produced by I₂ are less it will be limiting reactant.
Mass of PI₃ = moles × molar mass
Mass of PI₃ = 0.02 mol × 411.7 g/mol
Mass of PI₃ = 8.234 g
