Chem 110, First Exam Time : 90 min
2011 -
2
stterm
Model (A)
With the best wishes
General Chemistry Team work
Name:
Number:
Section:
Useful information:
NA=6 .02×1023 mol−1
[1] The halogen elements are found in ____ of the periodic table.
(A) Group 8A (B) Group 2A (C) 7th period (D) Group 7A *
[2] What is the number of carbon atoms in 0.35 mol of C6 H12O6
(A) 1.261024 atoms * (B) 11023 atoms (C) 2 atoms (D) 6 atoms
[3] Analysis of an unknown compound gave the following data: (C) 54.5%, (H) 9.09%, (O) 36.4%.
The molar mass is 88 g/mol. What is the molecular formula?
(A) C4H4O2
(B) C8H12O4
(C) C4H8O2 * (D) CHO
[4] The atomic masses of X(75.53%) and X(24.47%) are 34.968 amu and 63.956 amu, respectively. Calculate the average atomic mass of X element.
(A) 38.96 amu (B) 35.45 amu * (C) 38.47 amu (D) 71.92 amu
[5] Express 1x10-8 cm as nanometers.
(A) 1x10-19 nm (B) 1x101 nm (C) 1x10-10 nm (D) 1x10-1 nm *
Directions: for each of the following question, choose the letter that best answers the question and place it on your answer sheet
[6] Balanced the following equation in the smallest whole numbers:
-- KClO3 (s) ---KCl (s) + -- O2(g) (A) 1,1,3
(B) 2,1,2 (C) 2,2,3 * (D) 1,2,1
[7] Identify the ions and their charges Na2SO4
(A) Na+, SO4-
(B) Na+, SO42- * (C) Na+, SO4+
(D) Na2+, SO4+
[8] Calculate the percent of chlorine (Cl) in CHCl3
(A) 89.09% * (B) 78.09 % (C) 88.01 % (D) 99.09 %
[9] Which of these is SI-derived unit for density?
(A) Kg/m3 * (B) g/cm3 (C) g/mL (D) Kg/cm3
[10] What temperature is 77K when converted to ºC?
(A) 50 °C (B) -126 °C (C) 67.8 °C (D) -196 °C *
[12] How many grams of CS2 are there in 2.55 mol of CS2? (A) 621.3 g
(B) 119.4 g (C) 942.6 g (D) 194.2 g *
[13] Which of these quantities represents the largest mass?
(A) 0.05 Kg * (B) 500 mg (C) 5 x 103 µg (D) 5 g
[14] Which of these equations is correct?
(A) 0C= (0F + 32)/1.8 (B) 0C= (0F - 32)/1.8 * (C) 0C= (0F + 32) 1.8 (D) 0C= (0F + 32-1.8)
[15] What is the mass in grams of one atom of iron?
(A) 9.28 10-23 g * (B) 6.02 1023 g (C) 1.66 10-24 g (D) 5.81 10-23 g
] 16 Which of these elements is most likely to be a good conductor of electricity [
?
(A) N (B) He (C) Na * (D) H
[17] When 0.198 mol of N2 are reacted with 0.98 mol of H2 to form ammonia NH3, the actual yield of NH3 was 5.4g. Calculate the percent yield of the reaction.
(A) 75.4%
(B) 40.1%
(C) 48.1%
(D) 80.26%*
[18] The SI base unit of luminous intensity is...
(A) liter (B) meter (C) Candela * (D) mole
[19] Which is the correct formula for dichlorine hepoxide?
(A) Cl2(O)7
(B) Cl2O7 * (C) ClO7
(D) Cl2OH
[20] Which two of these ions have the same number or electrons?
(A) and
(B) and *
(C) and
(D) and
[21] The SI prefixes giga and micro represented respectively:
(A) 10-9 and 10-6 (B) 106 and 10-3 (C) 103 and 10-3 (D) 109 and 10-6 *
[22] Which pair of compounds has the same empirical formula?
(A) C2H6O3 and CH2O (B) C6H6 and CH4
(C) NO2 and N2O4 * (D) NO2 and N4O
[23] Determine the number of molecules of CO2 that present in 88g of CO2.
(A) 3.1 1024 molecules (B) 1.2 1024 molecules * (C) 2.4 1023 molecules (D) 4.2 1025 molecules [24] The correct name of NH4NO3 is....
(A) Ammonium nitrogen trioxide.
(D) Hydrogen nitrogen oxide.
[25] Which of these elements is metalloid?
(A) Ca (B) Mg (C) B * (D) Al
[26] Atoms of the same element with different mass numbers called:
(A) ions (B) isotopes * (C) neutrons
(D) chemical formula
[27] All the following statements are correct except:
(A) A chemical equation uses chemical symbols to show what happens during chemical reaction.
(B) The mass number indicates the total number of neutrons and protons in a nucleus.
(C) The molecular formula shows the number of atoms of each element in the simplest ratio of substance *.
(D) Elements in the same group of the periodic table exhibit similar properties.
[28] Which of the following molecule is a diatomic molecule?
(A) CH3O (B) CO * (C) C2H4
(D) CO2
[29] Given the following densities at 25ºC:
Magnesium: 1.7 g/cm3, iron: 7.9 g/cm3
A block of iron has a mass of 826g. What is the mass of a block of magnesium that has the same volume as the block of iron?
2NaCl + H2SO4 Na2SO4 + 2HCl (A) NaCl *
(B) H2SO4
(C) Na2SO4
(D) HCl
