Answer:
The correct option is d.
Explanation:
The reaction in the question is that for the formation of ammonia. The arrow in the reaction should be a reversible arrow. Because of the negative ΔH value, the forward reaction is exothermic while the reverse reaction is endothermic.
An increase in temperature of a system at equilibrium favors the endothermic reaction, hence the reverse reaction (the reactants) is favored. And when the reverse reaction is favored, more reactants are produced. Hence, product formation (at equilibrium) is not favored as the temperature is raised.
Answer:If we dissolve NaF in water, we get the following equilibrium:
text{F}^-(aq)+text{H}_2text{O}(l) rightleftarrows text{HF}(aq)+text{OH}^-(aq)
The pH of the resulting solution can be determined if the K_b of the fluoride ion is known.
20.0 g of sodium fluoride is dissolve in enough water to make 500.0 mL of solution. Calculate the pH of the solution. The K_b of the fluoride ion is 1.4 × 10 −11 .
Step 1: List the known values and plan the problem.
Known
mass NaF = 20.0 g
molar mass NaF = 41.99 g/mol
volume solution = 0.500 L
K_b of F – = 1.4 × 10 −11
Unknown
pH of solution = ?
The molarity of the F − solution can be calculated from the mass, molar mass, and solution volume. Since NaF completely dissociates, the molarity of the NaF is equal to the molarity of the F − ion. An ICE Table (below) can be used to calculate the concentration of OH − produced and then the pH of the solution.
Explanation:
Answer: Option C) 4 moles
Explanation:
The reaction below shows the decomposition of 2 moles of water to yeild 2 moles of hydrogen and 1 mole of oxygen respectively.
2H2O(l) --> 2H2(g) + O2 (g)
So, if 2 moles of H2O produce 1 mole of O2
8 moles of H2O will produce Z mole of O2
To get the value of Z, cross multiply
2 x Z = 1 x 8
2Z = 8
Z = 8/2
Z = 4
Thus, 4 moles of O2 is produced from the complete decomposition of 8 moles H2O .
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