Which of the following are true about balanced chemical reactions? (Select all that apply)
a. Atoms of each element are equal on both sides.
b. Chemical equations must be balanced to satisfy the Law of Conservation of Mass.
c. Coefficients are added to balance the equation.
d. It is better to change subscripts to balance equations.
e. All chemical formulas have a coefficient greater than one.
f. Balanced chemical equations help to determine the number of moles needed in the reaction.

the number of atoms of each element remains the same

b. Chemical equations must be balanced to satisfy the Law of Conservation of Mass.

Coefficients are added to balance the equation.

Explanation:

In order to balance the equation, we must change the amounts of the reactants and products, as necessary, by adding coefficients in front of the appropriate formula(s).

Chemical equations need to be balanced in order to satisfy the law of conservation of matter, which states that in a closed system matter is neither created nor destroyed.

what is the volume occupied by 40 grams of argon gas (ar) at standard conditions? what volume, in liters, is occupied by 1.5 x 1023