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Question
What is the pH of a buffered system made by dissolving 17.42 g of KH2PO4 and 20.41 g of K2HPO4 in water to give a volume of 200.0 mL? The Ka2 for dihydrogen phosphate is 6.2 10-8 and the equilibrium reaction of interest is
H2PO4-(aq) + H2O(l) 
H3O+(aq) + HPO4-(aq).
A) 7.03
B) 7.17
C) 7.38
D) 7.58
Answer
This answer is hidden. It contains 1 characters.
Related questions
Q:
In the following picture of an oxide, darkly-shaded spheres represent oxygen atoms or ions and lightly-shaded spheres represent atoms or ions of a third-row element in its highest oxidation state. Tell whether the oxide is covalent or ionic and whether the oxide is acidic or basic. A) covalent and acidic
B) covalent and basic
C) ionic and acidic
D) ionic and basic
Q:
Picture (a) shows p-orbital overlap between carbon and oxygen atoms; picture (b) shows p-orbital overlap between silicon and oxygen atoms. Based on these pictures, it is expected that
A) carbon and oxygen form better σ bonds than silicon and oxygen, so C-O single bonds are stronger than Si-O single bonds.
B) silicon and oxygen form better σ bonds than carbon and oxygen, so Si-O single bonds are stronger than C-O single bonds.
C) carbon and oxygen form better π bonds than silicon and oxygen, so C=O double bonds are stronger than Si=O double bonds.
D) silicon and oxygen form better π bonds than carbon and oxygen, so Si=O double bonds are stronger than C=O double bonds.
Q:
Which element shown on the periodic table above forms an interstitial binary hydride with the formula MXx?
A) element A
B) element B
C) element C
D) element D
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B) element B
C) element C
D) element D
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Q:
When 3.600 grams of anhydrous magnesium chloride were exposed to moist air, water was absorbed by the sample. If the resulting hydrated compound has a mass of 4.962 grams, what is the chemical formula of the hydrate?
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Q:
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B) H2SO4
C) CoCl2 6 H2O
D) Cu(OH)2
Q:
Indicate the coefficient in front of H2O2 when the following redox equation is balanced in an acidic medium.H2O2(aq) + MnO4-(aq) -> O2(g) + Mn2+(aq)A) 2B) 3C) 5D) 7
Q:
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B) H2O2
C) O2
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Q:
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Q:
Which of the following is a peroxide?
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B) a peroxide.
C) a superoxide.
D) an oxide and a superoxide.
Q:
Which of the following oxides has the highest melting point?
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C) D) SO3
Q:
Which will is least likely to form an interstitial hydride?
A) Si
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Which element most readily forms nonstoichiometric hydrides?
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Which transition metal hydride is commonly used in the purification of hydrogen gas?
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Q:
Covalent hydrides of the type MH3 are likely to form with elements of what group?
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Q:
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Q:
The bright colors of anodized titanium are due toA) electrodeposition of organic dyes on the titanium surface.B) the formation of a titanium alloy with chromium and copper.C) iridescence involving the semitransparent outer layer of TiO2.D) trapping of organic dye molecules in a spongy TiO2 matrix.
Q:
Chromium can be electroplated from an aqueous solution containing sulfuric acid and chromic acid, H2CrO4. What current is required to deposit chromium at a rate of 1.25 g/min?
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B) 38.7 A
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Q:
How many grams of chromium metal are plated out when a constant current of 8.00 A is passed through an aqueous solution containing Cr3+ ions for 40.0 minutes?
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Q:
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Q:
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Q:
A steel pipe can be protected from corrosion by attaching the pipe to a piece of magnesium because
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B) magnesium is more easily oxidized than iron.
C) magnesium is inert.
D) magnesium and steel form a corrosion resistant alloy.
Q:
Which of the following statements concerning the rusting of iron is false?
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B) The metal is reduced.
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D) Salt increases the rate of corrosion by providing ions to carry the current.
Q:
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