5 Select the correct answer.
A chemistry student heated Iron (a graylsh solid) with sulfur (a yellow solid) and observed a black, lumpy solid forming. What is the student's
conclusion?
A. A physical change has occurred, and a new substance has formed.
B. A chemical change has occurred, and a new substance has formed.
OC A physical change has occurred, and the reactants and products have the same properties.
D. A chemical change has occurred, and the reactants and products have the same properties.
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B.

Explanation:

The change in color and the indistinguishable states of the substances must indicate a chemical change.

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 !