REVIEW: Balancing Equations

Solid copper reacts with aqueous sulfuric acid (H₂SO₄) to form copper (II) sulfate and hydrogen gas.

• Cu(s) + H₂SO₄ (aq)--> CuSO₄ + H₂ (g)

• Cu + H₂SO₄ (aq)--> CuSO₄ + H (g)

• Cu + H₂SO₄ --> CuSO₄ + H₂

• Cu(s) + HSO₄ (aq)--> CuSO₄ + H₂ (g)

Answer explanation

Copper is stated as a solid so write Cu (s). Sulfuric acid contains an H⁺¹ in front and sulfate is SO₄^-2. Thus, aqueous sulfuric acid is H₂SO₄ (aq). Your products are Copper (II) Sulfate which is Cu⁺² and SO₄^-2 which will cancel out since +2 and -2 equal 0. Lastly, hydrogen gas should just be H₂.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Solid Iron reacts with aqueous sulfuric acid (H₂SO₄) to form iron (II) sulfate and hydrogen gas.

• Fe(s) + H₂SO₄ (aq)--> FeSO₄ + H₂ (g)

• Fe + H₂SO₄ (aq)--> FeSO₄ + H (g)

• Fe + H₂SO₄ --> FeSO₄ + H₂

• Fe(s) + HSO₄ (aq)--> FeSO₄ + H₂ (g)

Answer explanation

Iron is stated as a solid so write Fe (s). Sulfuric acid contains an H⁺¹ in front and sulfate is SO₄^-2. Thus, aqueous sulfuric acid is H₂SO₄ (aq). Your products are Iron (II) Sulfate which is Fe⁺² and SO₄^-2 which will cancel out since +2 and -2 equal 0. Lastly, chlorine gas should just be Cl₂.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

How many atoms are in NH₄

• 5

• 2

• 4

• 6

Tags

NGSS.MS-PS1-1

How many atoms are in C₂H₂O₄

• 6

• 8

• 3

• 7

Tags

NGSS.MS-PS1-1

How many sulfur atoms are in the compound Aluminum sulfate?

• 3

• 12

• 4

• 1

Answer explanation

Al has a charge of +3 and sulfate is SO₄^-2. When the signs criss cross you are left with Al₂(SO₄)₃.

Tags

NGSS.MS-PS1-1

How many oxygen atoms are in the compound barium sulfate?

• 3

• 12

• 4

• 1

Answer explanation

Ba has a charge of +2 and sulfate is SO₄^-2. The signs will cancel out and you are left with BaSO₄

Tags

NGSS.MS-PS1-1

Select the balanced reaction for the combustion of sodium.

• 4 Na (s) + 3 O₂ (g)--> 2 Na₂O₃(s)

• Na (s) + O₂ (g)--> Na⁺¹O^-2 (s)

• Na (s) + O₂ (g)--> NaO₃ (s)

• 4 Na (s) + 1 O₂ (g)--> 2 Na₂O (s)

Tags

NGSS.HS-PS1-7

_Al + _Cl₂ -> _AlCl₃ (do not put any spaces in between, for ex: 1,2,3,4)

_C₂H₄ + _O₂--> _CO₂ + _H₂O

• 1,3,2,1

• 1,3,2,2

• 2,5,4,1

• 1,2,3,4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What is a coefficient?

• The small number on the right of the chemical symbol.
• The large number to the left of a formula.

Tags

NGSS.MS-PS1-5