# chemistry Gopalgc1993.

1. Which of the following examples illustrates a number that is correctly rounded to three significant figures?

A) 4.05438 grams to 4.054 grams

B) 0.03954 grams to 0.040 grams

C) 103.692 grams to 103.7 grams

D) 109,526 grams to 109 500 grams

E) 20.0332 grams to 20.0 grams

2. The cubic centimeter (cm3 or cc) has the same volume as a

A) cubic inch.

B) cubic liter.

C) milliliter.

D) centimeter.

E) cubic decimeter.

3. Mercury has a specific gravity of 13.6. How many milliliters of mercury have a mass of 0.35 kg?

A) 0.0257 mL

B) 0.026 mL

C) 25.7 mL

D) 26 mL

E) 4760 mL

4. When a volcano erupts, 175 g of steam at 100.0 °C is released. How many kilojoules are lost when the steam condenses, then freezes, at 0.0 °C?

(Heat Vaporization = 2260 J/g , Specific heat = 4.184 J/g0C, Heat of Fusion = 334 J/g)

5. A cheeseburger from a fast food restaurant contains 19 g of fat, 20. g of carbohydrate, and 28 g of protein. How many kcal of energy does the cheeseburger contain? (The accepted caloric values for foods are 4.0 kcal/g for carbohydrate, 9.0 kcal/g for fat, and 4.0 kcal/g for protein.) Report the answer to 2 significant figures.

a) 70. kcal

b) 360 kcal

c) 400 kcal

d) 630 kcal

d) 280 kcal

6. Which of the answers for the following conversions contains the correct number of significant figures?

a) 2.543 m × = 100.1942 in

b) 2 L × = 2.12 qt

c) 24.95 min × = 0.4158 hr

d) 12.0 ft × × = 370 cm

e) 24.0 kg × = 11 lb

7. How many calories are required to increase the temperature of 13 g of alcohol from 11 °C to 23 °C? The specific heat of alcohol is 0.588 cal/g °C.

a) 83 cal

b) 0.63 cal

c) 92 cal

d) 0.54 cal

e) 170 cal

8. A 2.5 g sample of smashed potatoes is placed in a calorimeter with 300.0 g of water at an initial temperature of 25 °C. After combustion of the potatoes, the water has a temperature of 47 °C. What is the caloric value (kcal/g) of the smashed potatoes?

9. How many calories are required to raise the temperature of a 35.0 g sample of iron from 25 °C to 35 °C? Iron has a specific heat of 0.108 cal/g °C.

10. A dose of mortrin of 5.0 mg per kilogram of body weight has been prescribed to reduce the fever of an infant weighing 7.5 pounds. Calculate the number of milligrams of mortrin that should be administered.

11. Identify the physical state(s) corresponding to the regions on the cooling curve below. 12. A sample of chlorine has two naturally occurring isotopes. The isotope Cl-35 (mass 35.0 amu) makes up 75.8% of the sample, and the isotope Cl-37 (mass = 37.0 amu) makes up 24.3% of the sample. What is the average atomic mass for chlorine?

13. In a sulfuric acid solution, where the [ H3O+] is 0.01 M, what is the pH?

14. Write the correctly balanced equation for the complete neutralization of H3PO4 with Ca(OH)2?

15.  In a neutralization reaction, how many moles of HClO4 react with 1 mole of Al(OH)3?

16. When solutions of KCl and Pb(NO3)2 are mixed, a precipitate forms. Write the balanced equation for the double replacement reaction that occurs?

17. What is the concentration, in m/v percent, of a solution prepared from 50. g NaCl and 2.5 L of water?

18. How many moles of CaCl2 are in 250 mL of a 3.0 M of CaCl2 solution?

19. Use the reaction for Q 19:

2AgNO3(aq) + H2SO4(aq) → Ag2SO4(s) + 2H2O(l).

What volume of 0.123 M AgNO3(aq) is needed to form 0.657 g of Ag2SO4(s)?

20. What is the pressure, in mmHg, of a 4.00 g sample of O2 gas, which has a temperature of 30.0 °C, and a volume of 3000 mL?

21. A gas sample contains 4.0 g of CH4 and 2.0 g of He. What is the volume of the sample at STP?

22. SO3 (g) + H2O (l) → H2SO4(l)

a. What is the classification of this reaction?

b. How many molecules of SO3 are present in 1.3 moles of SO3?

c. How many moles of water will be reacted with 2.5 g of SO3 when 15g of H2SO4 is produced?

23. Draw the lewis structures for H20, NH3, CO2, CCl4 and BH3 (show all the steps for each structure)

24. Name the following compounds

a. Na2SO4

b. SF6

c. N2O3

d. CCl4

e. Ba(NO2)2

25. Write the correct formula for following compounds.

a. Di phosphorous pentoxide

b. Hydrogen peroxide

c. Calcium sulfite

d. Hydrogen cyanide

26. Write the electron configuration for Ca, P, N3-, Ar, S2-

27. Zn(s) + 2 HCl(aq) → H2(g) + ZnCl2(aq)

When 25.0 g of Zn reacts, how many L of H2 gas are formed at 25 °C and a pressure of 854 mmHg?

28.  What is the abbreviated electron configuration for nickel (atomic number 28)?

A) [He]2s22p3

B) [Ar]4s23d8

C) [Kr]4s23d8

D) [Ar]4s24p4

E) [Ar]3d8

29. In which of the following would the particles move most rapidly?

A) ice at -20 °C

B) water at 20 °C

C) steam at 110 °C

D) boiling water

E) ice at 0 °C

30. Which of the following is NOT true for the atoms 13N, 14N, and 15N?

A) They all have the same mass number.

B) They are isotopes.

C) They all have the same atomic number.

D) They all have 7 protons.

E) They all have 7 electrons

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