balancing equations\n● true or false: in a balanced equation, the number of atoms need to be equal.\n● true…

balancing equations\n● true or false: in a balanced equation, the number of atoms need to be equal.\n● true or false: you can change the subscripts in order to balance the equation.\n2\n● is this equation balanced? why or why not? cu + o2 ->cuo\n● what coefficient would need to go in front of h2o? n2h4 + o2 -> n2 + h2o\n● is this equation balanced? why or why not? mg + 2hcl ->h2 & mgcl2

balancing equations\n● true or false: in a balanced equation, the number of atoms need to be equal.\n● true or false: you can change the subscripts in order to balance the equation.\n2\n● is this equation balanced? why or why not? cu + o2 ->cuo\n● what coefficient would need to go in front of h2o? n2h4 + o2 -> n2 + h2o\n● is this equation balanced? why or why not? mg + 2hcl ->h2 & mgcl2

Answer

Explanation:

Step1: First True - False

In a balanced chemical equation, according to the law of conservation of mass, the number of atoms of each element on both sides must be equal. So the statement "In a balanced equation, the number of atoms need to be equal" is True.

Step2: Second True - False

To balance a chemical equation, we change the coefficients in front of the chemical formulas, not the subscripts. Changing subscripts would change the identity of the substances. So the statement "You can change the subscripts in order to balance the equation" is False.

Step3: Balance of Cu + O₂ -> CuO

On the left - hand side, we have 1 Cu atom and 2 O atoms. On the right - hand side, we have 1 Cu atom and 1 O atom. The number of O atoms is not equal on both sides. So the equation Cu + O₂ -> CuO is not balanced.

Step4: Coefficient for H₂O in N₂H₄+O₂ -> N₂ + H₂O

First, balance the H atoms. There are 4 H atoms in N₂H₄. So we need 2 moles of H₂O to balance the H atoms. The balanced equation is N₂H₄+O₂ -> N₂ + 2H₂O. The coefficient in front of H₂O is 2.

Step5: Balance of Mg + 2HCl -> H₂+MgCl₂

On the left - hand side, we have 1 Mg atom, 2 H atoms and 2 Cl atoms. On the right - hand side, we have 1 Mg atom, 2 H atoms and 2 Cl atoms. The number of atoms of each element is equal on both sides. So the equation Mg + 2HCl -> H₂+MgCl₂ is balanced.

Answer:

  • True or False: In a balanced equation, the number of atoms need to be equal. Answer: True
  • True or False: You can change the subscripts in order to balance the equation. Answer: False
  • Is this equation balanced? Why or why not? Cu + O₂ -> CuO. Answer: Not balanced. There are 2 O atoms on the left and 1 O atom on the right.
  • What coefficient would need to go in front of H₂O? N₂H₄ + O₂ -> N₂ + H₂O. Answer: 2
  • Is this equation balanced? Why or why not? Mg + 2HCl -> H₂+MgCl₂. Answer: Balanced. The number of atoms of each element is equal on both sides.