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- Calculate the molecular mass of table sugar sucrose (C 12 H 22 O 11 ).
A. 342.30 amu C. 320.05 amu B. 160.03 amu D. 171.15 amu
- How many oxygen atoms are in 34.5 g of NaNO 3?
A. (^) 2.34 1023 atoms C. (^) 7.33 1023 atoms B. (^) 5.81 1026 atoms D. (^) 8.2 1 1022 atoms
- Calculate the mass percent of oxygen in the amino acid, serine, which has the molecular formula C 3 H 7 NO 3.
A. 0.46% C. 13.33%
B. 15.22% D. 45.67%
- Aluminum chloride is 20.2% aluminum by mass. Calculate the mass of aluminum in a 35.0 gram sample of aluminum chloride.
A. 6.49 g C. 7.07 g B. 20.4 g D. 5.24 g
- A laboratory analysis of citric acid (compound responsible for the sour taste of lemons) determined the following mass percent composition 37.51% carbon, 4.20% hydrogen and 58.29% oxygen. Find the empirical formula.
A. C 3 H 4 O 3 C. C 6 H 8 O 5
B. C 6 H 8 O 7 D. C 5 H 8 O 7
- A compound has an empirical formula of CH 2 O and the molar mass of the compound is 180g/mol. What is the molecular formula?
A. CH 12 O C. C 6 H 12 O 6
B. C 6 H 6 O D. C 12 H 24 O 12
- Consider the following unbalanced chemical equation. When properly balanced, what is the coefficient of HCl?
HCl( aq ) + O 2 ( g ) → H 2 O( l ) + Cl 2 ( g )
A. 1
B. 2
C. 3
D. 4
- How many moles of NaBr are needed to react with 0.75 moles of Fe according to the following reaction?
Fe + 3NaBr → FeBr 3 + 3Na
A. 0.75 moles C. 0.25 moles B. 1.50 moles D. 2.25 moles
- Urea (CH 4 N 2 O) is a common fertilizer that can be synthesized by the reaction of ammonia with carbon dioxide:
2NH 3 ( aq ) + CO 2 ( aq ) → CH 4 N 2 O( aq ) + H 2 O( l )
Starting with 50.0 g of NH 3 , how many grams of CO 2 are required for the NH 3 to be completely consumed?
A. 64.6 g C. 1.47 g B. 129 g D. 25.0 g
- Solutions of calcium hydroxide, Ca(OH) 2 , and sodium phosphate, Na 3 PO 4 , are mixed. Write the balanced complete ionic equation for the reaction:
___Ca(OH) 2 ( aq ) + ____Na 3 PO 4 ( aq ) →
A. Ca2+( aq ) + 2OH( aq ) + 3Na+( aq ) + PO 43 ( aq ) → 3Na+( aq ) + 2OH( aq ) + CaPO 4 ( s ) B. 3Ca2+( aq ) + 2OH( aq ) + 3Na+( aq ) + 2PO 43 ( aq ) → 3Na+( aq ) + 2OH( aq ) + Ca 3 (PO 4 ) 2 ( s ) C. 3Ca2+( aq ) + 6OH( aq ) + 6Na+( aq ) + 2PO 43 ( aq ) → 6Na+( aq ) + 6OH( aq ) + Ca 3 (PO 4 ) 2 ( s ) D. 3Ca2+( aq ) + 2PO 43 ( aq ) → Ca 3 (PO 4 ) 2 ( s )
- It requires 23.56 mL of 0.105 M sodium hydroxide to neutralize 15.00 mL of a sulfuric acid (H 2 SO 4 ) solution. Determine the concentration of the sulfuric acid (H 2 SO 4 ) solution.
A. 0.0825 M C. 0.169 M
B. 0.0401 M D. 0.311 M
- What is the oxidation number of sulfur in SO 4 2−?
A. +4 C. +
B. − 2 D. +
- Which of the following are redox reactions?
I. CuSO 4 + 2NaOH → Cu(OH) 2 + Na 2 SO 4 II. 2Al + 3MgSO 4 → 3Mg + Al 2 (SO 4 ) 3 III. 2(NH 4 ) 3 PO 4 + 3Ba(NO 3 ) 2 → Ba 3 (PO 4 ) 2 + 6NH 4 NO 3 IV. 2HNO 3 + 3H 3 AsO 3 → 2NO + 3H 3 AsO 4 + H 2 O
A. I and II C. All of them B. III and IV D. II and IV
- Convert 32 pounds per square inch (psi) into mmHg. (Note: 14.7 psi = 1 atm, 1 Pa = 1N/m2, 1 atm = 101.325 Pa, 1mmHg = 1 torr)
A. (^) 8.1 102 mmHg C. 1.7 × 103 mmHg B. (^) 1.0 105 mmHg D. 2.2 mmHg
- A balloon has an initial volume of 3.45 L. What will the volume be if the temperature is raised from 24°C to 32°C?
A. 3.54 L C. 3.35 L
B. 4.60 L D. 2.58 L
- What is the volume occupied by 20.0 g of argon gas at a pressure of 1.05 atm and a temperature of 25.0 C?
A. 39.1 L C. 466 L
B. 11.7 L D. 0.978 L
- Determine the density in g/L of an unknown gas given that a 14.5 gram sample contains 2.00 moles at 25oC and 745 mmHg.
A. 0.00123 g/L C. 3.49 g/L B. 49.1 g/L D. 0.291 g/L
- A 1.00 L mixture of helium, hydrogen, and xenon gas has a total pressure of 645 torr at 298 K. If the partial pressure of helium is 341 torr and the partial pressure of hydrogen is 112 torr, how many moles of xenon are present in the mixture?
A. (^) 0.130 10 ^2 mol C. (^) 1.13 10 ^3 mol B. (^) 1.13 10 ^1 mol D. (^) 1.03 10 ^2 mol
- A system absorbs 185.5 kJ of heat as it expands to do 592 J of work (by the system) on the surroundings. What is the change in internal energy of the system?
A. 184.9 kJ C. 186.6 kJ B. (^) 409.9 kJ D. 722.9 kJ
- In recent years, scientists have become concerned about the quantity of which one of the following gases rising in the atmosphere and trapping heat, thus causing global warming?
A. CO C. NO 2
B. CO 2 D. CF 4
- What are the correct coefficients to balance the following equation and what is the oxidation number for Mn on the left (reactant)?
KMnO 4 + HCl → KCl + MnCl 2 + H 2 O + Cl 2
A. (1,8,1,1,7,3) ; 7 C. (2,16,6,4,7,2) ; +
B. (2,16,2,2,8,5) ; +7 D. (4,8,1,4,10,7) ; +
CHE 105 FALL 2012 Exam 2 key
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