Ahot dog bun (volume 215 cm3) with a density of 0.11 g/cm3 is crushed in a picnic cooler into a volume of 135 cm3. what is the new density of the bun?

The answer to your question is:  density = 0.175 g/cm3

Explanation:

Data

v1 = 215 cm3

density1 = 0.11 g/cm3

v2 = 135 cm3

mass = ?

Formula

density = mass/volume

First, calculate mass

mass = density x volume   mass = 0.11 X 215 = 23.65 g

Now, calculate density with the second volume

 density = 23.65 g / 135 cm3

density = 0.175 g/cm3

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !