An empty beaker is weighed and found to have a mass of 323 6 grams A piece of metal is then placed inside the beaker which is then reweighed and found to have a mass of 366 7 grams The metal is then removed and 50 7 milliliters of water is added to the beaker The metal is then placed back inside the beaker and the new volume on the beaker reads 55 9 milliliters a Calculate the density of the metal in g mL c What volume in nL does a sample of the metal with a mass of 548 kg occupy b Convert this density to cg m3 1 2014 Marcus Jennings 2 An unknown substance containing only carbon hydrogen and oxygen is burned to produce 6 46 grams of carbon dioxide and 2 64 grams of water The total mass of the compound before combustion was 4 40 grams a What mass in grams of carbon was in the sample b What mass in grams of hydrogen was in the sample c What mass in grams of oxygen was in the sample d What is the empirical formula of the compound e If the molar mass of the compound is 180 2 g mol what is the molecular formula f Write a balanced chemical equation representing this scenario 2014 Marcus Jennings There are two known stable isotopes of bromine 79Br and 81Br The average atomic mass of bromine is 79 904 amu a Calculate the percent abundance of each isotope b How many moles of bromine are in one mole of magnesium bromide c How many bromine atoms are in 2 37 grams of ammonium bromate d What is the percent composition of bromine in hypobromous acid 3 2014 Marcus Jennings 4 A solution of copper II sulfate is made by dissolving 75 0 grams of copper II sulfate in 650 milliliters of water Solid zinc metal is then placed in the solution a What is the molarity of the copper II sulfate solution before zinc is added b Write a balanced net ionic equation the represents this scenario c What mass in grams of zinc is required to completely with all of the copper II ions in the solution d Write the half reactions for each element that experiences a change in oxidation state 2014 Marcus Jennings 5 250 milliliters of a 0 97 M hydrochloric acid solution is added to 320 mL of a 0 37 M barium hydroxide solution The initial temperature of each solution was 23 1 C After the solutions are mixed the temperature increases to 32 9 C Assume that the heat capacity and density of the solution are the same as water 4 184 J g C and 1 00 g mL respectively a Write a balanced net ionic equation that demonstrates this situation b Determine the pH of the solution of the solution after the two solutions are mixed c Calculate the enthalpy of reaction for the combination of hydrochloric acid and barium hydroxide d What volume of the original acid solution would be required to obtain 23 8 grams of hydrochloric acid e Suppose that acetic acid was used instead of hydrochloric acid What would the identity of the conjugate acid and the conjugate base be 2014 Marcus Jennings 86 2 grams of magnesium metal is placed in a solution of strong acid and reacts completely a Write a balanced net ionic equation for this process b What volume of gas is produced if the reaction happens at STP c Calculate the work done by this gas d Write the half reactions for each element that experiences a change in oxidation state 6 2014 Marcus Jennings The work function for gold is 8 17 x10 19 Joules The mass of an electron is 9 11 x10 31 kg a What is the maximum wavelength in nm of light required to dislodge an electron from gold b Suppose that radiation with a wavelength of 200 nm is used to irradiate the gold Calculate the velocity of the ejected electron c What is the de Broglie wavelength of this electron 7 2014 Marcus Jennings Inside of a hydrogen lamp electricity is used to excite hydrogen atoms Electrons transition from the n 7 to the n 1 a Calculate the change in energy when electrons transition from the excited state to the ground state in the hydrogen lamp b What is the wavelength in nm of the associated photon c Is this photon absorbed or emitted d How many moles of these photons are required to heat 100 grams of water from 25 C to the boiling point 8 2014 Marcus Jennings Consider the formation of magnesium bromide from its elements The enthalpy of reaction for the formation of magnesium bromide is 1048 6 kJ The heat capacity of iron is 0 444 J g C a Write the reactions associated with a Born Haber cycle that can be used to calculate the lattice energy of this compound b How much heat is released when 500 grams of magnesium bromide are formed c To what temperature can 100 grams of iron be heated to if the initial temperature of the iron is 10 0 C and all the heat released from forming 500 grams of magnesium bromide is transferred to the iron 9 2014 Marcus Jennings 10 Explain the following a The atomic radius of beryllium is smaller than that of barium b The first ionization energy of nitrogen is less than that of fluorine and neon c The electron affinity of magnesium is positive whereas the electron affinity of sulfur is negative d The electron configuration of copper is Ar 4s13d10 2014 Marcus Jennings 11 Consider the following bromine tribromide silicon tretrafluoride nitrogen pentahydride and the nitrate ion a Draw the Lewis structure s for each of these b What are the electron domains of each of these c What are the molecular geometries of each of these d Describe the type of bonding in terms of the hybridization that the central atom experiences in each of these molecules 2014 Marcus Jennings 12 Below is a graph of the energy required for successive ionizations The element lies in the second period a What is the general electron configuration for the elements that would exhibit this type of trend in ionization energies ex nsx n 1 dy b What is the identity of the element c To what element is this atom isoelectronic to if only the first 3 ionizations occur d Of the two which is larger and why 2014 Marcus Jennings See provided Lewis structure of 4 pentynoic acid a How many sigma and pi bonds are in this molecule b What is the hybridization of the carbon that is attached to both oxygen atoms c How much energy in kJ mol would be required to completely break this molecule up into atoms 13 2014 Marcus Jennings 14 Consider the following N2H2 and CF2H2 a Draw each structure so that it does not exhibit a dipole moment b Draw each structure so that it does exhibit a dipole moment c Consider the following reaction 3 N2H2 2N2 2NH3 What …
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