Shown below is a balance. Based on this instrument, identify from the following list all the statements that are true if you wer
e to use
this balance to measure the mass of a sample. (Note, the balance in the picture currently reads "0.00")
Choose one or more:
A. a mass measured on this balance will always have 3 significant digits.
B. the uncertainty is in the hundredth place.
C. the uncertainty is in the ones place.
D. a mass measured on this balance will always have 4 significant digits.
E. the uncertainty is in the tenths place.
F. the mass measured on this balance is known exactly.
G. a mass that falls between 1 gram and 9 grams measured on this balance will always have 3 significant figures.
H. a mass that falls between 10 grams and 80 grams measured on this balance will always have 3 significant figures.
I. a mass that falls between 100 and 200 grams measured on this balance will have 5 significant figures.
this balance to measure the mass of a sample. (Note, the balance in the picture currently reads "0.00")
Choose one or more:
A. a mass measured on this balance will always have 3 significant digits.
B. the uncertainty is in the hundredth place.
C. the uncertainty is in the ones place.
D. a mass measured on this balance will always have 4 significant digits.
E. the uncertainty is in the tenths place.
F. the mass measured on this balance is known exactly.
G. a mass that falls between 1 gram and 9 grams measured on this balance will always have 3 significant figures.
H. a mass that falls between 10 grams and 80 grams measured on this balance will always have 3 significant figures.
I. a mass that falls between 100 and 200 grams measured on this balance will have 5 significant figures.
1 answer:
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Answer:
a) [H₃O⁺] = 1.8x10⁻⁵ M
b) pH = 4.75
c) % rxn = 3.5x10⁻³ %
Explanation:
a) The dissociation reaction of HCN is:
HCN(aq) + H₂O(l) ⇄ H₃O⁺(aq) + CN⁻(aq)
0.5 M - x x x
The dissociation constant from the above reactions is given by:
By solving the above quadratic equation we have:
x = 1.75x10⁻⁵ M = 1.8x10⁻⁵ M = [H₃O⁺] = [CN⁻]
Hence, the [H₃O⁺] is 1.8x10⁻⁵ M.
b) The pH is equal to:
Then, the pH of the HCN solution is 4.75.
c) The % reaction is the % ionization:
Therefore, the % reaction or % ionization is 3.5x10⁻³ %.
I hope it helps you!