When referring to mass sum of the atomic masses of the atoms represented by the formula of a molecular substance, the correct term used is A. atomic mass B. formula weight C. molecular mass D. molecular weight 12. A mole of CO2 contians A. 6.02 x 1023 ions C. 6.02 x 1023 formula ions B. 6.02 x 1023 molecules D. 6.02 x 1023 atoms 13. The mass of the products in a chemical reaction depends on the amount of A. excess reactant B. limiting reactant C. oxidizing agent D. reducing subtannce 14.
(c) Calculate the mass of water formed when 20 g of methane undergoes complete combustion. 6 Deduce the empirical formulae of the following: Moles and empirical formulae 1 Calculate the molar mass of these compounds. (Relative atomic masses H = 1; N = 14; O = 16; Mg = 24; S = 32; Ca = 40; K =39; Cr = 52; Fe = 56.) (a) calcium ethanoate, Ca(CH3CO2)2 (b) chromium sulfate Cr2(SO4)3 (c) magnesium hydroxide, Mg(OH)2 (d) potassium cyanoferrate(III), K3Fe(CN)6 2 When 2.4 g of magnesium
8.1 10) The halogens, alkali metals, and alkaline earth metals have __________ valence electrons, respectively. A) 7, 4, and 6 B) 1, 5, and 7 C) 8, 2, and 3 D) 7, 1, and 2 E) 2, 7, and 4 Answer: D Diff: 2 Page Ref: Sec. 8.1
If 63% of the mass of pyrolusite is due to manganese, what is the empirical formula of pyrolusite? • MnO • Mn2O • Mn2O2 • MnO2 4. A compound with an empirical formula of C2H4Br has a molar mass of 215.90 g/mol. What is the molecular formula? • C4H8Br2 • C2H4Br • CHBr • C6H12Br3 5.
Practice Test for 6.1-6.3 1. Complete the following molarity calculations: a. What is the molarity of a solution containing 25.3 grams of copper (II) chloride dissolved in 140 mL of water? b. How many grams of sodium hydroxide are needed to make 2 L of a 0.05 M solution?
Data Table 2: Mass, Volume and Temperature during Dissolution of Urea (To calculate Keq) Mass of Urea(g) (±0.01g) | Initial Temperature(Cº) (±0.2 Cº) | Final TemperatureCº) (±0.2 Cº) | Initial Volume(mL)(±0.05 mL) | Final Volume(mL)(±0.05 mL) | 3.76 | 21.4 | 22.9 | 5.02 | 7.14 | Processing Raw Data * Determining the Final temperature of dissolution of Urea in the Styrofoam cup. Graph 1: The Change in temperature due to the Dissolution of Urea In order to calculate the final temperature of the dissolved mixture, the linear fit of the graph was utilized. The final time measure was 600 seconds. Substituting the value of time in to the linear equation:- Temp= 0.008997 ºC/s (600) + 17.25 ºC Final Temperature= 17.8 ºC ±0.2 ºC * Calculation of enthalpy change Using the formula Q = m * C * (∆T) m= mL of Water C= Heat Capacity ∆T= Change in Temperature m = 50.0 mL ± 0.01 mL c = 4.184 J g-1 ºC-1 ∆ T= 17.4 Cº (±0.2 C) - 21. 8 Cº
14.1 Multiple-Choice and Bimodal Questions 1) Consider the following reaction: [pic] The average rate of appearance of B is given by[pic]. Comparing the rate of appearance of B and the rate of disappearance of A, we get [pic] A) -2/3 B) +2/3 C) -3/2 D) +1 E) +3/2 Answer: B Diff: 1 Page Ref: Sec. 14.2 2) Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: [pic] In a particular experiment at 300 °C, [pic]drops from 0.0100 to 0.00650 M in [pic] The rate of appearance of [pic] for this period is __________ M/s. A) [pic] B) [pic] C) [pic] D) [pic] E) [pic] Answer: A Diff: 1 Page Ref: Sec. 14.2 3) Which substance in the reaction below either appears or disappears the fastest?
Identify the condensed formula of the following structure: A) (CH3)2CHCHClCH(CH3)2 B) CH3CH(CH3)CHClCH(CH3)2 Ans: C C) D) (CH3)2CHCHClC(CH3)3 (CH3)3CCHClCH(CH3)3 9. What is the chemical formula of the following carbon skeleton diagram? A) C8H14 Ans: C B) C8H16 C) C8H18 D) C8H20 10. How many hydrogen atoms are there on carbon atoms 1 and 2, respectively, in the structure below? A) 4, 1 B) 4, 0 Ans: D C) 3, 1 D) 3, 0 11.
Physics: Principles and Applications, 6e Giancoli Chapter 17: Electric Potential Conceptual Questions 1) Which of the following is not a vector? A) electric force B) electric field C) electric potential D) electric line of force Answer: C Diff: 1 Type: MC Var: 1 Page Ref: Sec. 17.1-17.8 2) One joule per coulomb is a A) newton. B) volt. C) electron-volt.
Which one of the following molecules has tetrahedral geometry? A. CF4 B. XeF4 C. BF3 D. NH3 E. AsF5 63. A molecule with 3 single bonds and 0 lone pairs of electrons is predicted to have which type of molecular geometry? A. Trigonal planar B. Trigonal pyramidal C. Bent D. Trigonal bipyramidal E. Linear 64. A central atom with 4 electron pairs (single bonds and/or lone pairs of electrons) could have which of the following molecular geometries?