OC userin ChemistryΒ·17 Dec 2017102. A metal with a threshold frequency of 6.71 x 104 semits an electron with a velocity of 6.95 X 10m/s when radiation of 1.01 x 10155 strikes the metal. Calculate the mass of the electron.
OC userin ChemistryΒ·14 Dec 201784. What mass of lead sulfate is formed in a lead-acid storage bat- tery when 1.00 g of Pb undergoes oxidation?
OC userin ChemistryΒ·13 Dec 2017Q2. Which statement is true for voltaic cells? a) Electrons flow from the anode to the cathode. b) Electrons flow from the more negatively charged electrode to the more positively charged electrode. c) Electrons flow from higher potential energy to lower potential energy d) All of the above are true.
OC userin ChemistryΒ·13 Dec 20173. Three 5 L flasks each contain 4 g of gas at room temperature. Flask 1 contains H2. Flask 2 contains He and Flask 3 contains CH4. Which of the following statements is true? a) The molecules of flask 3(CH4) have the highest average kinetic energy. b) The flasks all contain equal moles of gases. c) The pressure in Flask 3(CH4) is the highest. d) The density of Flask 3(CH4) is the highest. e) The collision frequency is greatest in Flask 1 (H2).
OC userin ChemistryΒ·12 Dec 201710. Find the pH of a buffer prepared by mixing 200.0 mL of 0.200 M NaCN with 400.0 mL of 0.150 M HCN. K. (HCN) 4,00 x 10-10 [3 marks]
OC userin ChemistryΒ·10 Dec 201714. Does a large positive electrode potential indicate a strong oxidiz- ing agent or a strong reducing agent? What about a large nega- tive electrode potential?
OC userin ChemistryΒ·12 Dec 2017111. Which statement is true? a. A spontaneous reaction is always a fast reaction. b. A spontaneous reaction is always a slow reaction. c. The spontaneity of a reaction is not necessarily related to the speed of a reaction.
OC userin ChemistryΒ·9 Dec 201740. Give each ionic compound an appropriate name. a. BaS b . FeCl3 c. Pb14 d. SrBr2
OC userin ChemistryΒ·10 Dec 2017127. The ratio of oxygen to nitrogen by mass in NO2 is 2.29. The ratio of fluorine to nitrogen by mass in NF3 is 4.07. Find the ratio of oxygen to fluorine by mass in OF.
OC userin ChemistryΒ·10 Dec 20175. There are two naturally occurring isotopes of chlorine with ratios of 76% and 24%. One mole of PCI is made using a sample of isotopically pure chlorine gas (containing only one of the two isotopes). The product weighs 142 g. If chlorine gas containing the other isotope were used, one mole of the PC13 would weigh: (a) 136 g (b) 139 g (c) 145 g (d) 133 g (e) 127 g
OC userin ChemistryΒ·8 Dec 20176) Consider 5.72 g of propane (CzH; FW = 44.1 g/mol) b) Calculate the number of carbon atoms in the sample.
OC userin ChemistryΒ·9 Dec 201793. These reactions are important in catalytic converters in automobiles. Calculate AGΒΊ for each at 298 K. Predict the effect of increasing temperature on the magnitude of AGΒ°. a. 2 CO(g) + 2NO(g) = N2(g) + 2 CO2(8) b. 5 H2(g) + 2 NO(g) β> 2 NH3(g) + 2 H2O(g) c. 2 H2(g) + 2NO(g) = N2(g) + 2 H2O(8) d. 2 NH3(g) + 2 02(g) β> N2O() + 3 H2O(g)
OC userin ChemistryΒ·9 Dec 20171. Explain why lizards become sluggish in cold weather. How is this phenomenon related to chemistry?
OC userin ChemistryΒ·9 Dec 2017135. What relative masses of dimethyl amine and dimethyl ammo- nium chloride do you need to prepare a buffer solution of pH = 10.43?
OC userin ChemistryΒ·9 Dec 201757. Which buffer system is the best choice to create a buffer with pH = 7.20? For the best system, calculate the ratio of the masses of the buffer components required to make the buffer. HC2H302/KC2H302 NH/NH4Cl HCIO2/KCIO HCIO/KCIO