Answer:
Explanation:
The usefulness of a buffer is its ability to resist changes in pH when small quantities of base or acid are added to it. This ability is the consequence of having both the conjugate base and the weak acid present in solution which will consume the added base or acid.
This capacity is lost if the ratio of the concentration of conjugate base to the concentration of weak acid differ by an order of magnitude. Since buffers having ratios differing by more will have their pH driven by either the weak acid or its conjugate base .
From the Henderson-Hasselbach equation we have that
pH = pKa + log [A⁻]/[HA]
thus
0.1 ≤ [A⁻]/[HA] ≤ 10
Therefore the log of this range is -1 to 1, and the pH will have a useful range of within +/- 1 the pKa of the buffer.
Now we are equipped to answer our question:
pH range = 3.9 +/- 1 = 2.9 through 4.9
Answer:
32.3 dm³
Explanation:
Data given:
no. of molecules of Cl₂ = 8.7 x 10²³
Volume of chlorine gas (Cl₂) = ?
Solution:
First we have to find number of moles
For this formula used
no. of moles = no. of molecules / Avogadros number
no. of moles = 8.7 x 10²³ / 6.022 x 10²³
no. of moles = 1.44 moles
Now we have to find volume of the gas
for this formula used
no. of moles = volume of gas / molar volume
molar volume = 22.4 dm³/mol
Put values in above equation
1.44 moles = volume of Cl₂ gas / 22.4 dm³/mol
rearrange the above equation
volume of Cl₂ gas = 1.44 moles x 22.4 dm³/mol
volume of Cl₂ gas = 32.3 dm³
Answer:
Covalent bond.
Explanation:
There are two kinds of chemical bonds: covalent bonds and ionic bonds.
- A covalent bond is formed when two atoms share a pair of electrons (two electrons for each bond.)
- Ions are formed when one atom transfers an electron to another. Ionic bonds refer to the attraction between ions of opposite electric charges.
In this example, since the atoms are sharing atoms, the chemical bond between them would be a covalent bond.
738.1146 grams, your're welcome