Ihave trouble figuring out these questions

1. a metal ball has a mass of 2kg and a volume of 6m to the third power. what is its density?

2. a certain gas expands to fill a 3l container. its madd is measures to be 0.6 kg what is the density?

3. a solid is 5cm tall, 3 cm wide and 2 cm thick it has a mass of 129g. what is its density?

4. in terms of volume, how do ml and cm to the third power relate to one another?

5. a graduated cylinder is filled to an initial volume of 12.7 ml. a rock is dropped into the graduated cylinder. the final volume of the graduated cylinder is 18.2 ml what is the rocks volume?
what method was used to determine this?

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

6.4 cm (max) - 25 cm (min)