THE CITY UNIVERSITY OF NEW YORK Chemistry 1040 July 2, 2018 BROOKLYN COLLEGE Fou
ID: 704596 • Letter: T
Question
THE CITY UNIVERSITY OF NEW YORK Chemistry 1040 July 2, 2018 BROOKLYN COLLEGE Fourth Examination Name PART I. TURN OFF ALL CELL PHONES!!! YOU MAY NOT LEAVE DURING THE TEST! . Which of the following is not an example of a colligative property of a solution? a. boiling point depression c. osmotic pressure b. freezing point depression d. all are examples 2. Which of the following is a weak base? a. NHy b. NaC c. HF d. NaOH 3. Which of the following will influence the rate of a reaction? a. increasing the concentration of reactants c. addition of a catalyst b. decreasing the temperature d. all of the above 4. Which of the following solutions has the greatest osmolarity? a. 0.1 M NaCI b. 0.2 M CaCh c. 0.3 M glucose d. 0.4 M NH, 5. As the concentration of HyO decreases, the a. pH increases b. pH decreases c. pOH increases d.the pH remains the same 6. Which is not an example of a solution? a. soda b. air c. milk d. salt water 7. The energy required initiate a chemical reaction is called a. specific heat b. heat of fusion c. activation energy d. ionization ener 8 An organic molecule which changes color in different chemical environments is called b. indicator c. amphiprotic d. acid a. isotope at 25 C, the solution is considered to be a. saturated 9. The solubility of sugar is 67 /100 mL at 25°C. If 67 g of sugar is placed in 150 mL o b. unsaturatedExplanation / Answer
1. The answer is a.As it is not boiling point depression,it is boiling point elevation.which means that the temperature of a solution is more than pure solvent.
2.The answer is a. As NH3 doesn't completely dissociates in water.NaCl is a salt,HF is a weak acid,NaOH is a strong base.
3.The answer is d.As increase in concentration of reactant increase rate , adding a catalys lowers down the activation energy hence increase rate of reaction,decrease in temperature lowers the collision and lower rate of reaction.
4. The answer is b.
osmolarity = molarity x number of particle upon dissociation
osmolarity of 0.1 M NaCl = 2 x 0.1 =0.2 osmole
0.2 M CaCl2 = 3 x 0.2 = 0.6 osmoles
for glucose osmolarity = molarity =0.3 because it is not an electrolyte.
osmolarity of nh3 = 0.4 x 1 = 0.4 osmoles
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