Answer:
0.056moles HF and 0.70M
Explanation:
When a strong acid is added to a buffer, the acid reacts with the conjugate base.
In the system, NaF and HF, weak acid is HF and conjugate base is NaF. The reaction of NaF with HCl (Strong acid) is:
NaF + HCl → HF + NaCl
Initial moles of NaF and HF in 60.0mL of solution are:
NaF:
0.0600L × (0.80mol / L)= 0.048 moles NaF
HF:
0.0600L × (0.80mol / L)= 0.048 moles HF
Then, the added moles of HCl are:
0.0200L × (0.40mol / L) = 0.008 moles HCl.
Thus, after the reaction, moles of HF produced are 0.008 moles + the initial 0.048moles of HF, moles of HF are:
<em>0.056moles HF</em>
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In 20.0mL + 60.0mL = 80.0mL = 0.0800L, molarity of HF is:
0.056mol HF / 0.0800L = <em>0.70M</em>
Answer:
D is the correct answer.
Explanation:
I took the test on A pex. Everyone make sure you look at your answers. They are NOT always in the same order.
To go from molecules to moles divide by Avogadro's number [<span>6.02x10^23]</span>
Example:
1.50x10^23 divided by 6.02x10^23 = 0.249 moles rounded to three significant figures
Atoms are electrically neutral because they have equal numbers of protons positively charged and electrons negatively charged.if an atom gains or loses one or more electrons it becomes an ion
