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The gases: F2, H2, N2, and O2 at STP are represented in the plot. Which gas corresponds to curve II?   

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.

The systematic name for the compound Fe2(SO4)3 is ______.

Which arrow on the phase diagram corresponds to the particle-level phase change shown?       

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? N2(g) + O2(g) ⇌ 2NO(g)    Kc = 0.10 at 2000 °C  

The figure represents the initial contents of a reaction vessel mixture of nitrogen monoxide (NO) and oxygen (O2) at a pressure of 1 atm. Keeping the volume and temperature constant, what are the final total pressure (Ptot) and partial pressure of nitrogen dioxide (PNO2) when the reaction is complete (assuming a 100% yield)? 2NO(g) + O2(g) → 2NO2(g)   

What isotope is depicted in the figure?          

How many sigma (σ) and pi (π) bonds are in the molecule shown?   

Which of these are most important for the formation of the blood brain barrier?

Which of the following types of glands work by secreting its products by exocytosis?