When balanced, which equations would have the coefficient 3 in front of the first set of atoms? check all that apply. a. agbr + gapo4 → ag3po4 +gabr3 b. h2so4 + b(oh)3 → b2(so4)3 + h2o c. fe + agno3 → fe(no3)2 + ag d. c2h4o2 +o2 → co2 +h2o

The correct answer is A. AgBr + GaPO₄ --> Ag₃PO₄ + GaBr₃.

You can see right away that there are 3 silver atoms on the right side, and for that we will need 3 silver atoms on the left side. That would require adding a coefficient of 3 in front of the first set of atoms. And you can see that by adding this coefficient of 3 in front of AgBr, this will make 3 atoms of Br on the left side. There is already 3 atoms of bromine on the right side. This makes the equation balanced.

To balance the equation in answer choice B, you get
H₂SO₄ + B(OH)₃ --> B₂(SO₄)₃ + H₂O
H₂SO₄ + 2B(OH)₃ --> B₂(SO₄)₃ + H₂O
B is now balanced
3H₂SO₄ + 2B(OH)₃ --> B₂(SO₄)₃ + H₂O
SO₄ is now balanced
3H₂SO₄ + 2B(OH)₃ --> B₂(SO₄)₃ + 6H₂O
Oxygen and hydrogen are now balanced.
B is also a correct answer.

To balance the equation in answer choice C, you get
Fe + AgNO₃ --> Fe(NO₃)₂ + Ag
Fe + 2AgNO₃ --> Fe(NO₃)₂ + Ag
NO₃ is now balanced
Fe + 2AgNO₃ --> Fe(NO₃)₂ + 2Ag
Ag is now balanced

C is not a correct answer as the first set of atom doesn't have a coefficient of 3.

To balance the equation in D
C₂H₄O₂ + O₂ --> CO₂ + H₂O
You can see that the O₂ on the left will take care of the O₂ (in CO₂) on the right. This means that the O₂ in C₂H₄O₂ will take care of the O in H₂O.
C₂H₄O₂ + O₂ --> 2CO₂ + H₂O
Carbons are now balanced.
C₂H₄O₂ + 2O₂ --> 2CO₂ + 2H₂O
Hydrogen and oxygen atoms are balanced.

The correct answer is A and B.

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