Answer:
<em>The pKa is 13.0.</em>
Explanation:
pKa + pKb = 14
Given, Kb of trimethylamine = 6.3 ×
pKb = - log (6.3 × )
= 1.0
⇒ pKa = 14 - pKb = 14 - 1.0
<u>pKa = 13.0</u>
<em><u></u></em>
<em>Check: For most weak acids, pKa ranges from 2 to 13.</em>
Answer:
a
Explanation:
all elemental metals are made up of only one type of element
Initiation <span>occurs when mRNA, tRNA, and an amino acid meet up inside the ribosome. </span>Elongation occurs when amino acids are continually added to the line, forming a long chain bound together by peptide bonds.
<span>An atom's identity, that is, whether it is 'oxygen' or 'plutonium', for example, is determined solely by the number of protons in the nucleus. The number of neutrons also plays a part - a differing number of neutrons can change an atom from one isotope of an element into another, but the atoms would still remain the same element, albeit a different isotope. The number of electrons orbiting the atom does not change the identity of the atom, only it's electronic state. Take electrons away and it becomes a positively charged ion of the same element. Add electrons and it becomes a negatively charged ion, but still of the same element.</span>
Answer:
Explanation:
We want to convert from moles to grams, so we must use the molar mass.
<h3>1. Molar Mass</h3>
The molar mass is the mass of 1 mole of a substance. It is the same as the atomic masses on the Periodic Table, but the units are grams per mole (g/mol) instead of atomic mass units (amu).
We are given the compound PI₃ or phosphorus triiodide. Look up the molar masses of the individual elements.
- Phosphorus (P): 30.973762 g/mol
- Iodine (I): 126.9045 g/mol
Note that there is a subscript of 3 after the I in the formula. This means there are 3 moles of iodine in 1 mole of the compound PI₃. We should multiply iodine's molar mass by 3, then add phosphorus's molar mass.
- I₃: 126.9045 * 3=380.7135 g/mol
- PI₃: 30.973762 + 380.7135 = 411.687262 g/mol
<h3>2. Convert Moles to Grams</h3>
Use the molar mass as a ratio.
We want to convert 3.14 moles to grams, so we multiply by that value.
The units of moles of PI₃ cancel.
<h3>3. Round</h3>
The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we calculated, that is the tens place.
The 2 in the ones place tells us to leave the 9.
3.14 moles of phosphorous triiodide is approximately equal to <u>1290 grams of phosphorus triodide.</u>