3.A thin lead apron is used to protect patients from harmful X rays. If the sheet measures 75.0 cm by 55.0 cm by 0.10 cm, and the density of lead is 11.3 g/cm3, what is the mass of the apron in grams?

4.67 kg

Explanation:

Given data

Step 1: Calculate the volume of the sheet

The volume of the sheet is equal to the product of its dimensions.

Step 2: Calculate the mass of the sheet

The density (ρ) is equal to the mass divided by the volume.

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 !