CHM1045 Practice Q A 1 A tentative explanation for a set of observations that can be tested by further experimentation is referred to as a A theory b A law c A hypothesis d None of the above 2 Atoms of the same element with different mass numbers are called a Ions b Neutrons c Groups d Isotopes 3 Complete the following chart Electrons Atomic Number Protons Al3 S2 4 Write the empirical formula C6H14O 5 Write the formula Rubidium nitrite 6 Write the empirical formula C10H22O2 7 Write the formula Lead II Carbonate 8 Name the compound KOH 9 Write the formula Calcium hydrogen phosphate 10 Name the compound KMnO4 11 Name the compound FeCl3 6H2O 12 Is temperature an extensive or intensive property 13 Is sodium an alkali metal or alkaline earth metal 14 Hydrogen gas burns in oxygen gas to form water Is hydrogen burning a physical or chemical property 15 What isotope is used as the standard in establishing the atomic mass scale 16 Liquid nitrogen boils at 195 8 C Express the boiling point of liquid nitrogen in kelvin 17 The average distance from Earth to the sun is 9 3x107 miles How many kilometers is this Express your answer in scientific notation 18 Complete the following chart 14N3 Atom Ion 195Pt 26 Protons 28 Neutrons 24 Electrons 19 Bromine is extremely dense with density 3 10g cm3 How many liters will 2 12g of bromine occupy 20 Write the formula for the compound Magnesium nitride 21 Name the compound K2CO3 2H2O 22 Chlorine exists mainly as two isotopes 35Cl and 37Cl with atomic masses of 24 968 amu and 36 956 amu respectively Calculate the average atomic mass of chlorine knowing that 35Cl isotope is 75 53 abundant 23 Combustion analysis of 0 9437 gram sample of the compound ferrocene gave 2 233 grams of CO2 and 0 457 grams of H2O Ferrocene is composed of C H and Fe What is the empirical formula of ferrocene 24 Which of the following compounds is a strong electrolyte a H2O b Glucose C6H12O6 c NaCl d Acetic acid CH3COOH 25 What is the oxidation number of Cr in Cr2O72 26 Consider the following redox reaction Mg s 2H2O l Mg OH 2 aq H2 g a Assign oxidation numbers to the following elements Reactants Mg H Products Mg H in H2 b Which reactant is oxidized 27 Determine the number of hydrogen atoms that are present in 25 6 grams of NH4 3PO4 28 Determine the amount of heat in kJ given off when 1 26 x 104 g of NO2 are produced according to the equation 2 NO g O2 g 2 NO2 g H 114 6 kJ mol 29 When 0 1375g sample of solid magnesium is burned in a constant volume bomb calorimeter the temperature of the calorimeter rises from 25 0 C to 26 2 C a Is the combustion of magnesium endothermic or exothermic b If the heat capacity of the calorimeter is 3024 J C calculate the heat of reaction for the combustion of 0 1375g of Mg c What is the change of energy when 1 mole of Mg is burned 30 CO2 gas effuses into an evacuated chamber in 48 seconds An unknown gas effuses into the same chamber in 34 seconds Determine the molar mass of the unknown gas 31 For a hydrogen atom the energy of 3p orbital is circle one Lower than the same as higher than the energy of 3s orbital 32 Which of the following atoms would you expect to have the largest first ionization energy a Cs b Li c Na d Rb 33 Which of the following atoms ions is isoelectronic with O2 Circle all that apply a Ne b Na c F 34 Which of the following has the largest atomic radius a N b Si c P Electrons 10 14 54Fe2 26 28 24 13 16 Answers Protons 13 16 Atomic Number 1 C 2 D 3 Al3 S2 4 C6H14O 5 RbNO2 6 C5H11O 7 PbCO3 8 Potassium Hydroxide 9 CaHPO4 10 Potassium Permanganate 11 Iron III Chloride Hexahydrate 12 Intensive 13 Alkali metal 14 Chemical 15 12Carbon 16 77 4K 17 1 5 x 108 km 18 Atom Ion 14N3 Protons 7 Neutrons 7 Electrons 10 19 6 84 x 10 4 L 20 Mg3N2 21 Potassium Carbonate Dihydrate 22 35 45 amu 23 C10H10Fe 24 C 25 6 26 a Assign oxidation numbers to the following elements Reactants Mg 0 H 1 Products Mg 2 H in H2 0 b Which reactant is oxidized Mg 27 1 24 x 1024 atoms H 28 1 57 x 104 kJ 29 a exothermic b 3629 J c 641 2 kJ mol 195Pt 78 117 78 30 21 9g 31 the same as 32 B 33 A and B 34 B
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