Answer:
2.25g of NaF are needed to prepare the buffer of pH = 3.2
Explanation:
The mixture of a weak acid (HF) with its conjugate base (NaF), produce a buffer. To find the pH of a buffer we must use H-H equation:
pH = pKa + log [A-] / [HA]
<em>Where pH is the pH of the buffer that you want = 3.2, pKa is the pKa of HF = 3.17, and [] could be taken as the moles of A-, the conjugate base (NaF) and the weak acid, HA, (HF). </em>
The moles of HF are:
500mL = 0.500L * (0.100mol/L) = 0.0500 moles HF
Replacing:
3.2 = 3.17 + log [A-] / [0.0500moles]
0.03 = log [A-] / [0.0500moles]
1.017152 = [A-] / [0.0500moles]
[A-] = 0.0500mol * 1.017152
[A-] = 0.0536 moles NaF
The mass could be obtained using the molar mass of NaF (41.99g/mol):
0.0536 moles NaF * (41.99g/mol) =
<h3>2.25g of NaF are needed to prepare the buffer of pH = 3.2</h3>
I think the charge is +2
Hope this helps
Answer:
Explanation:
Speed is distance covered per unit time.it is a scaler quantity. It unit is m/s.
Velocity is speed in a given direction.it is a vector quantity. It unit is m/s.
Acceleration is the rate of increase in velocity.it is a vector quantity.it unit is m/s^2
A ratio of 0.89% w / v or 0.0089 in fraction means that
there is 0.89 weight of NaCl pero volume of solution. Therefore the mass of
NaCl is:
mass NaCl = 0.0089 * 200
<span>mass NaCl = 1.78 grams</span>
Answer:
2
Explanation:
Tried out 1, but couldn't get whole numbers on the right side then, so went up to 2, worked
all four numbrrs: 2, 7, 4, 6
The 7 for oxygen got adjusted in the last step of the thinking, because it's the simplest to adjust.
since there are different prime numbers (or rather numbers that don't share prime factors) in the set, the numbers can't be revived by the same number and still give whole numbers as results (they can't be smaller)
