1) One mole represents  a) 2.06 x 10^23 b) 6.02 x 10^23 c) 0.62 x 10^23 d) 10.23 x 62 2) The International Committee for Weights and Measures (ICWM) defines one mole as the number of atoms in exactly: a) 12 grams of any metal b) 1 gram of any metal c) 1 gram of carbon-12 (12C) d) 12 grams of carbon-12 (12C) 3) Since 12C’s molar mass is 12 grams, 48 grams of 12C atoms would be equal to ____ moles. a) 2 b) 4 c) 6 d) Answer can not be determined 4) Avogadro’s number acts as the conversion factor for converting between the number of moles in a sample and the number of molecules in the sample. a) True b) False 5) If there are 0.20 moles in 8.9 grams of CO2, what is the number of CO2 molecules? Use this equation to find the answer: Moles in sample (mol) x Avogadro's number (6.022 x 1023) = Number of sample molecules a) 0.20 x 10^23 b) 1.2 x 10^23 c) 8.9 x 10^23 d) 20 x 10^23 6) An element’s molar mass and atomic weight are always equal. a) True b) False 7) The element Vanadium has two stable isotopes 50V and 51V. The mass and abundance of these isotopes are 50V = 49.9472 amu and .0025 abundance and 51V = 50.9440 amu and .9975 abundance. With this information, what is the atomic weight of Vanadium? a) 23 b) 49.947 c) 50.944 d) 50.9415 8) The atomic weight of Hydrogen is 1.0079 amu and the atomic weight of Oxygen is 15.999 amu. Using this information, what is the molecular weight of a molecule of water, H2O? a) 2.016 amu b) 17.007 amu c) 18.015 amu d) Unknown 9) The number of neutrons present in an atom of mass number 133 and atomic number 55 is a) 55 b) 78 c) 133 d) 188 10) At rtp the hydrogen gas will occupy in dm^3? a) 24 b) 273 c) 11.2 d) 100 e) 5.6 11) The mass of Sulphur in 6g of SO2 is a) 4g b) 3g c) 2.5g d) 2g e) 5g 12) 7.3g HCl(g) will occupy __________ at stp (in dm^3) a) 22.4 b) 11.2 c) 2.8 d) 2.24 e) 4.48 13) The empirical formula is a) the one found by the experiment b) the same as the molecular formula c) the simplest ratio of atoms d) none of the above 14) The relative formula mass of CO2 is a) 28 b) 32 c) 56 d) 44 15) What are true about ISOTOPES? a) different number protons b) different number neutrons c) different number of electrons d) different proton and neutron number 16) When limestone (CaC03) is heated, Calcium oxide (CaO) is formed. Calculate the mass of Ca) produced by heating 25g of limestone. (RAM of C=12, O=16 and Ca=40) a) 1.78g b) 0.56g c) 14g d) 28g 17) Calculate the volume of carbon dioxide produced at rtp when excess HCl is added to 1.00g of calcium carbonate. (RAMs: C=12, O=16, Ca=40) a) 24dm^3 b) 2.4dm^3 c) 0.24dm^3 d) 0.024dm^3 18) What is the maximum mass of aluminum which you could add to an excess of dilute hydrochloric acid so that you produce no more than 100cm^3 of hydrogen at rtp. a) 1333.33g b) 133.3g c) 0.00075g d) 0.075g 19) Find the empirical formula of a compound containing: 1.6g O, 12.8g Cu a) CuO b) Cu2O c) Cu2O2 d) Cu2O3 20) Find the percentage by mass of copper in malachite, CuCO3.Cu(OH)2 *RAM: Cu-64, C-12, O-16, H-1 a) 28.9% b) 58.2% c) 57.7% d) 64.0%

F3 Chemistry MOLES

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