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What is the pH of a 2.5 M solution of acetic acid at equilibrium? (Balanced eq: HC2H3O2(aq) + H2O(l) + ⇌ H3O+(aq) + C2H3O2−(aq);  Ka of HC2H3O2 is 1.8 × 10−5  Note, X is much smaller than original concentration, therefore you do NOT need to perform the quadratic equation.  [Hint: What is the definition of pH?]

50.0 grams of arsenic powder is mixed with 50.0 grams of oxygen gas, as noted by the following balanced equation.  How many grams of diarsenic trioxide is produced?  (Molecular masses: Arsenic = 74.92 g/mol; Oxygen = 16.00; Diarsenic trioxide = 197.84 g/mol) Balanced Equation:  4As(s) + 3O2(g) –> 2As2O3(s) [HINT: How many equations are required to determine the answer?]  

Which of the following chemical reactions (numbered 1 – 3) depict(s) the forward reaction of a weak acid? Reaction 1: HCl → H+ (aq) + Cl− (aq) Reaction 2: HC2H3O2 ⇌ H+ (aq) + C2H3O2− (aq) Reaction 3: NH3(aq) + H + (aq) ⇌ NH4 + (aq) [Hint: Firstly, how do you identify a compound as an acid?]

Which collision factor most directly benefits from heating a reaction mixture?

A lab assistance prepares 2.50 liters of a 0.5000 M KCl solution.  What mass of KCl was used to prepare this particular solution? (Molar masses of K = 39.098 g/mol, Cl = 35.45 g/mol)  — [HINT: What units can you use to “M”?]

In the interest of enhanced buffering capacity, what is the best way to prepare an acidic buffer? [HINT: Read the each answer in its entirety]

Consider the function on R2 (R is the set of Real numbers) u(x,y)=min{x2y,xy}. What is the maximizer of f in the set {(x,y): x+5y=10}? (Hint: consider a vector in the hyperplane (1 5).(x,y)=10; when can this vector be a maximizer of u if x2y>xy? What if x2y

Given a function g:X->R (R is the set of Real numbers), the binary relation associated with g, is defined as follows: {(x,y):g(x) ≥ g(y)}. Let f:R->R be the function f(x)=x2. Which of the following functions has the same associated binary relation as f?

Let f:Rn->R (here R is the set of Real numbers) be a continuous functions. Let x in Rn and consider the set A={y in Rn: f(y) ≥ f(x)}. Then,

Consider the function u(x1,x2)=min{x12,x2}. Let p=(1 2) and w=1. Among the vectors {x≥0:p.x≤1}, which one maximizes u?