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>
Answer:
whah the other dude said :) also stay safe
Explanation:
Thickness of cooper sheet is 0.048 cm (Approx.)
Given that;
Density of copper = 8.96 g/cm³
Measures of copper sheet = 5.5 cm × 5.5 cm
Mass of of copper sheet = 12.96 gram
Find:
Thickness of cooper sheet
Computation:
Volume = Mass / Density
Volume of cooper = 12.96 / 8.96
Volume of cooper = 1.4464
Volume of cooper = 1.45 cm³ (Approx.)
Volume of cooper sheet = 5.5 cm × 5.5 cm x Thickness
5.5 cm × 5.5 cm x Thickness = 1.45
Thickness of cooper sheet = 0.04793
Thickness of cooper sheet = 0.048 cm (Approx.)
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brainly.com/question/24235924?referrer=searchResults
Answer:
Scientific experiments need to be repeated so that scientists can make sure the results are as accurate as possible.
Explanation:
The point of a scientific experiment is to find the answer to a question. If a scientist performs an experiment only one time, they might find an answer to their question. However, they might have messed something up, so the answer is completely wrong. Doing an experiment momre than once can help a scientist make sure that their answer is correct. I hope this helps!
Answer:
C. Double Replacement
Explanation:
A. Wrong because SR uses a compound and element. This equation is a compound and compound.
B. Wrong because it does not have O2 in the formula. All combustion reactions must have O2.
C. Correct because it is a compound reacting with a compound.
D. Wrong because the reactants did not form a single product. ex. (x + y > xy)
E. Wrong because the equation did not start with a single compound and break down. ex. (xy > x + y)
