[H_{3}O^{+}] = 0.00770 M
The equilibrium equation representing the dissociation of 

Given [H_{3}O^{+}] = 0.00770 M
Let the initial concentration of acid be x and change y
So y =
=
= 0.00770 M



0.00257 x - 0.00001979 = 0.00005929
x = 0.031 M
Therefore, initial concentration of the weak acid is <u>0.031 M</u>
Many elements show very strong similarities to each other.<span>For example, lithium (Li), sodium (Na), and potassium (K) are all soft, very reactive metals.
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Answer: The elements with properties intermediate between those of metals and nonmetals are called semimetals (or metalloids).
Answer: This is known as substitution cipher.
Explanation: