Chemistry, 30.09.2019 04:30 desi0322

When 0.880 g of an organic compound containing carbon, hydrogen and oxygen is burned completely in oxygen, 1.760 g of co2 and 0.720 g h2 o are produced. what is the empirical formula of the compound?

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1) Balance of mass

CxHyOz + O2 ---> CO2 + H20

0.880 g + X = 1.760g + 0.720 g

=> X = 1.760g + 0.720g - 0.880g = 1.6 g of O2

2) C in CO2:

molar mass of CO2 = 44 g/mol

=> 12 g C / 44 g CO2 * 1.760 g CO2 = 0.480 g C

3) H in H2O

molar mass of H2O = 18.0 g/mol

2 g H / 18.0 g H2O * 0.720 g H2O = 0.080 g H

4) O

4a) O in CO2: 32gO / 44 g CO2 * 1.760 g CO2 = 1.280 g O

4b) O in H2O: 16gO / 18 gH2O * 0.720 g H2O = 0.640 g O

4c) O in CxHyOz = 1.280 g + 0.64 g - 1.6 g = 0.320 g O

5) Convert grams into moles

C: 0.480 g / 12 g/mol = 0.04 mol
H: 0.08 g / 1 g/mol = 0.08 mol
O: 0.32 g / 16 g/mol = 0.02 mol

6) Divide by the smallest number

C: 0.04 / 0.02 = 2
H: 0.08 / 0.02 = 4
O: 0.02 / 0.02 = 1

7) Use those numbers as subscripts for the empirical formula:

C2 H4 O

C2H4O

Answer from: Quest

the energy to form plasma comes from heat or electricity in the atmosphere!

sunny~ ☺

Answer from: Quest

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.