Asilver voltmeter, copper voltameter and oxygen voltameter are connected in series. given that 4.32g of silver is deposited during the electrolytic process, determine(i) the mass of copper deposited(ii) the volume of oxygen liberated (ag=108, cu=64, o=16, g. m.v=22.4dm³

Additional information: aqueous silver always has a +1 charge aqueous copper has a +2 charge in voltameters solids always have a 0 charge gaseous oxygen is diatomic and will be notated as oxygen2 *since subscript/superscript is not available full names are written out in place of atomic symbols to add clarity. 1) write a balanced equation (numbers in parenthesis indicate charge): total reaction: silver(+1) + copper(0) -> silver(0) + copper(+2) half reaction: silver (+1) + e- -> silver (0) half reaction: copper(0) -> copper (+2) + 2e- need to multiple the silver half reaction by two to balance the number of electrons: half reaction: 2silver (+1) + 2e- -> 2silver (0) half reaction: copper(0) -> copper (+2) + 2e- now the electrons cancel out for a total reaction of: 2silver(+1) + copper(0) -> 2silver(0) + copper(+2) 2) convert the amount of silver to moles using the molar mass of silver (make sure units cancel): 4.32g of silver x (1 mole of silver/108g) = 0.04 moles of silver 3) convert silver to copper using the stoichiometry of the balanced equation (make sure units cancel): 0.04 moles of silver x (1 mole copper / 2 moles of silver) = 0.02 moles of copper 4) cover moles of copper to the mass of copper using the molar mass of copper (make sure units cancel): 0.02 moles of copper (64g / 1 mole of copper) = 1.28 of copper Objects in a series will experience the same current so REPEAT FOR OXYGEN. 1) write a balanced equation total reaction: silver(+1) + oxygen(-2) -> silver(0) + oxygen2(0) balance the molecules in the reaction total reaction: silver(+1) + 2oxygen(-2) -> silver(0) + oxygen2(0) half reaction: silver (I) + e- -> silver (0) half reaction: 2oxygen(-2) -> oxygen2(0) + 4e- need to multiple the silver half reaction by four to balance the number of electrons: half reaction: 4silver (+1) + 4e- -> 4silver (0) half reaction: 2oxygen(-2) -> oxygen2(0) + 4e- now the electrons cancel out for a total reaction of: 4silver(+1) + 2oxygen(-2) -> 4silver(0) + oxygen2(0) 2) convert the amount of silver to moles using the molar mass of silver (make sure units cancel): 4.32g of silver x (1 mole of silver / 108g) = 0.04 moles of silver 3) convert silver to oxygen using the stoichiometry of the balanced equation (make sure units cancel). Remember to compare solid silver to gaseous, diatomic oxygen: 0.04 moles of silver x (1 mole oxygen2 / 4 moles of silver) = 0.01 moles of oxygen2 4) convert moles of oxygen to the liters of oxygen using the G.M.V. (make sure units cancel): 0.01 moles of oxygen x (22.4dm3 / 1 mole of oxygen) = 0.224 dm3 of copper

Answer: abeexplanation:

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.