1) What is the molar concentration of a solution that is made by dissolving 6.30g of sodium chloride and diluting 1.00L?Report your answer to three significant figures.
2) In an experiment, 6.00g of Mg(s) was reacted completely with O2(g) to form MgO(s) and 148.5kJ of heat was evolved. What is the molar emthalpy of formation of MgO(s)? Report your answer in kJ/mol,to three significant figures.
3) What is the de Broglie wavelength of an electron travelling at 4.0X10^7 m/s? Report your answer in metres, in scientific notion, to two significant figures. (Me=9.109X10^-31 kg)
4) What is the energy of a photon having a wavelength of 610nm? Report your answer in joules, in scientific notion, to two significant figures.
5) Write the electron configuration of selenium.
6) Write the chemical equation for the reaction of CO2 with water.
7) What is the electron configuration o a Cu^3+ ion.
8) List the following ions in order of increasing ionic radius: O^2-, F-, Na+, Mg^2+.
9) List the following compounds in order of increasing lattice energy: NaCl, NaBr, MgO, CaO.
10) Draw a Lewis structure for PO4^3- that minimizes formal charges.© BrainMass Inc. brainmass.com October 24, 2018, 10:18 pm ad1c9bdddf
Assorted general chemistry problems are solved showing full working.
Chemistry: Orbitals and Electron Configurations, deBroglie Wavelengths
The following 5 problems concern electron configuration, the shape of orbitals, and calculation of Bohr wavelengths. Please see the attached file for the fully formatted problems.
1. A hydrogen atom in a certain excited state has its electron in a 5f subshell. The electron drops down to the 3d subshell, releasing a photon in the process.
a) For each of these subshells. Give the n and 1 quantum numbers, and give the range of possible ml quantum numbers.
b) How many radial nodes and how many angular nodes does each of the orbitals in part a) have?
c) Determine the wavelength of light that would be emitted by this process.
d) The hydrogen atom now has a single electron in the 3d subshell. Calculate the energy (in kJ/mol) required to ionize this (excited state) hydrogen atom. This is the energy required to remove the electron completely from the atom.
a) Write the ground-state electron configuration and count the number of unpaired electrons in cesium.
b) The photoelectric binding energy of cesium is 183.7 kJ/mol. Light having a wavelength of 2.4 x iO in falls upon a cesium surface in an evacuated tube. Calculate the minimum deBroglie wavelength of the emitted photoelectrons.
3. For each of the following orbitals, provide a perspective sketch of the orbital in the Cartesian x, y, z coordinate system. Determine the number of angular nodes and the number of radial nodes in the orbital, and describe where those nodes fail. (For instance. the 2Px orbital has an angular node in the yz-plane.)
a) 1s b) 3px c) 3dx2-y2 d) 3dxz
4. Write the ground-state electron configuration and count the number of unpaired electrons in:
Si, Ni, Ir, and Gd
5. Identify the atom or ion corresponding to each of the following descriptions:
a) An atom with ground-state electron configuration [Kr]4d105s25p1
b) An atom with ground-state electron configuration [Xe]4f 145d66s2
c) An ion with charge ?2 and ground-state electron configuration [Ne]3s23p6
d) An ion with charge +4 and ground-state electron configuration [Ar]3d3