Very small semiconductor crystals, composed of approximately 1000 to 10,000 atoms, are palled quantum dots. Quantum dots made of the semiconductor CdSe are now being used in electronic reader and tablet displays because they emit light efficiently and in multiple colors, depending on dot size. The density of CdSe is 5.82 g/cm3
a. What is the mass of one 2.5-nm CdSe quantum dot?
b. CdSe quantum dots that are 2.5 nm in diameter emit blue light upon stimulation. Assuming
that the dot is a perfect sphere and that the empty space in the dot can be neglected,
calculate how many Cd atoms are in one quantum dot of this size.
c. What is the mass of one 6.5-nm CdSe quantum dot?
d. CdSe quantum dots that are 6.5 nm in diameter emit red light upon stimulation. Assuming that
the dot is a perfect sphere, calculate how many Cd atoms are in one quantum dot of this size.
e. If you wanted to make one 6.5-nm dot from multiple 2.5-hm dots, how many 2.5-nm dots
would you need, and how many CdSe formula units would be left over, if any?
Want to see the full answer?
Check out a sample textbook solutionChapter 3 Solutions
CHEMISTRY THE CENTRAL SCIENCE 14TH EDI
- A solution is prepared by dissolving 2.50 g of Co(NH3)2Cl2 in 500.0 mL solution which results in a yellow color solution with a wavelength of 93.8 nm. 1. Calculate the density of this solution 2. Calculate the molarity of this soultion. 3. Write the Noble gas electron configuration of the element X. 4. If an electron relaxes from the 6th energy level at this wavelength, what is the final energy level where this electron will reside? 5. Calculate the number of photons by determing the number of molecules in the sample of Co(NH3)2CI2 6. Calculate the total energy that the soultion will produce. 7. Is this solution exothermic or endothermic? 8. Determine the oxidation number of the metal in this complex. 9. Is the metal ion in this complex paramagnetic or diamagnetic?arrow_forward5. For sulfur, the fluorides SF2, SF4, and SF6 are known to exist, whereas for oxygen only OF2 is known to exist.arrow_forward7) The reason why can ionic substances conduct electricity when in solution or molten, but not when they are in the solid state is- O a. The ions are free to move but not free to move in the solid state. O b. The neutrons are free to move but not free to move in the solid state. O c. The protons are free to move, but not free to move in the solid state. O d. The atoms are free to move, but not free to move in the solid state.arrow_forward
- 1. What are the possible sets of quantum numbers that can describe a 2p electron in an atom? 2. Give the electron configuration of Be. Draw the orbital diagram.3. Give the electron configuration of B. Draw the orbital diagramarrow_forwardIt takes 242. kJ/mol to break a chlorine-chlorine single bond. Calculate the maximum wavelength of light for which a chlorine-chlorine single bond could be broken by absorbing a single photon. Be sure your answer has the correct number of significant digits. nm 0 10 Xarrow_forward1.Which compound is used in respirators since it reacts with CO2(g) to produce O2(g)? a.RbO2 b.CsO2 c.KO2 d.MgO 2.Which of the following ion has the MOST number of unpaired electrons in the 3d orbital? a.Cu2+ b.Zn2+ c.Fe3+ d.Cr3+arrow_forward
- 25. The photoelectric effect can be used to find which property? a. Electron Affinity b. Reactivity C. lonization Energy d. Atomic Radius 26. What charge will S have as in ion? 27. Order the following elements from most to least reactive. Mg, Si, O, Ne, K 28. Which is a true statement about solid nonmetals? a. They have a shiny and lustrous surface b. They conduct electricity and heat C. They are magnetic and ductile d. They are non-conductive, brittle, and non-ductile 29. Which statement best describes a valence electron. a. The electrons found close to the nucleus b. The electrons that are found in the outermost shell of the atom c. The total number of electrons d. Electrons that are not involved in chemical properties M SAMSUNGarrow_forwardWhich following element has the condensed electron configuration [Kr] 4d¹⁰ ? a. Germanium (Ge) b. Palladium (Pd) c. Gadolinium (Gd) d. Yttrium (Y) e. Vanadium (V)arrow_forwardDue to inert pair effect, the elements of group IV having electronic configuration ns’, np? will form A. M" cation i. B. M" cation c. M' cation D. M²" cation ii. Which of the following is not an alternative ozone depleting Chlorofluorocarbon (CFCS)? A. Hydrocarbons B. CO, C. Hydrofluorocarbons D. Perfluorocarbons(PFCS) iii. Double bond is formed as a result of: A. Addition Reaction B. Polymerization Reaction C. Substitution Reaction D. Elimination Reaction iv. Which region of electromagnetic spectrum is involved in NMR spectroscopy? A. Radio waves B. Ultraviolet C. Visible D. Microwaves v. Which of the following oxide is used as a Catalyst in Contact process? C. Fe,O3 Which of the following alcohols will be most easily dehydrated to give an alkene? B. 2-methyl 2-prepanol Which of the following can undergo Aldol Condensation reaction? A. V,0; В. Р.0, D. Mn;03 vi. A. 3- Propanol С. 1-prepanol D.2-prepanol vii. A. Benzaldehyde B. Trimethylacetaldehyde C. Formaldehyde D. Acetaldehyde…arrow_forward
- If a single C-C bond has a bond energy of 346 kJ/mol, could a single photon in the visible range with a wavelength of 550 nm break this bond? O it cannot be calculated or determined. O no. O yes. O only if the C-C bond is part of a large biomolecule. + Post a new auestion hulu stv MacBook Pro + 2$ & %3D 4 5 7 8. { Y U F G J. .. .-arrow_forwardPhotoelectron spectroscopy applies the principle of the photoelectric effect to study orbital energies of atoms and mol ecules. High-energy radiation (usually UV or x-ray) is absorbed by a sample and an electron is ejected. The orbital energy can be calculated from the known energy of the radiation and the mea sured energy of the electron lost. The following energy differences were determined for several electron transitions: ∆E2→1 = 4.098x10-17 J ∆E3→£1 = 4.854x10-17 J ∆E5→1 = 5.242x10-17 J ∆E4→2 = 1.024x10-17 J Calculate ∆E and l of a photon emitted in the following transitions: (a) level 3 → 2; (b) level 4 → 1; (c) level 5→4.arrow_forward5. Energy from radiation can cause chemical bonds to break. To break a nitrogen-nitrogen bond in N2 gas, 941kJ/mole is required. a. Calculate the wavelength of radiation that could break the bond. b. In what spectral range does this radiation occur?arrow_forward
- General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage Learning