How many grams of aluminum sulfide can form from the reaction 9.00 g of aluminum with 8.00 g of sulfur

Answer : The mass of aluminum sulfide form from the reaction can be 12.5 grams.

Solution : Given,

Mass of Al = 9.00 g

Mass of = 8.00 g

Molar mass of Al = 27 g/mole

Molar mass of = 256 g/mole

Molar mass of = 150.2 g/mole

First we have to calculate the moles of Al and .

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

From the balanced reaction we conclude that

As, 3 mole of react with 16 mole of

So, 0.0312 moles of react with moles of

From this we conclude that, is an excess reagent because the given moles are greater than the required moles and is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of

From the reaction, we conclude that

As, 3 mole of react to give 8 mole of

So, 0.0312 moles of react to give moles of

Now we have to calculate the mass of

Therefore, the mass of aluminum sulfide form from the reaction can be 12.5 grams.

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.