What is the pH of a buffer made by combining 45.0 mL of 0.150 M nitrous acid and 20.0 mL of 0.175 M sodium nitrite? The Ka of nitrous acid, HNO2, is 4.5×10–4.   

For the reaction of nitrogen and oxygen to form nitrogen dioxide, N2(g) + 2O2(g) ⇌ 2NO2(g)   Kc = 1.5×103 If the reaction mixture is found to contain 2.0 M NO2 and 0.10 M N2 and 0.10 M O2, what is the value of Q and what does this mean?

What mass (in grams) of iron (Fe, molar mass = 55.85 g/mol) is needed to experimentally produce 50.0 g of iron(III) oxide (Fe2O3, molar mass = 159.70 g/mol) in excess oxygen if the percent yield is 78.7%?                              4Fe(s) + 3O2(g) → 2Fe2O3(s)

Which atomic orbital corresponds to this set of quantum numbers in a ground state atom of boron?                         (2, 1, –1, ½)

Which molecular compound could be dinitrogen monoxide?

If a 1.0 L flask is filled with 0.22 mol of N2 and 0.22 mol of O2 at 2000°C, what is [NO] after the reaction establishes equilibrium? Kc = 0.10 at 2000°C N2(g) + O2(g) ⇌ 2NO(g)

Consider the reaction potential energy diagram. What describes the uncatalyzed reverse reaction pathway?

For the galvanic cell: Zn(s) + 2Tl+(aq) → 2Tl(s) + Zn2+(aq)   Eocell = 0.42 V If the standard reduction potential for: Zn2+(aq) + 2e– → Zn(s)   Eored = –0.76 V What is the standard reduction potential for: Tl+(aq) + e– → Tl(s)   Eored = ? V

A weak species is titrated with a strong acid or base. Was the species a weak acid or a weak base and what is the corresponding pKa or pKb?

Which molecule has 4 sigma (σ) bonds?