Which reaction obeys the law of conservation of mass?

• Li + O₂ → 2 Li₂O

• CaI₂ + Hg(NO₃)₂ → HgI₂ + 2 Ca(NO₃)₂

• 2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O

• 2 PbO₂ → PbO + 2 O₂

Tags

NGSS.HS-PS1-7

Which reaction below shows aluminum reacting with iron (III) oxide to produce iron and aluminum oxide?

• Al₂O₃ + 2 Fe → 2Al + Fe₂O₃

• 2Al + Fe₂O₃ → 2Fe + Al₂O₃

• Al → Fe₂O₃ + Al₃O₃

• Al₂O₃ + Fe₂O₃ → Al + Fe

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

Look at the chemical reaction: 4 P + 5 O₂ → P₂O₅. Does it obey the law of conservation of mass?

• yes, it is properly balanced

• no, you need more phosphorus atoms on the reactant side

• no, you need more oxygen atoms on the product side

• no, you need more phosphorus and oxygen atoms on the product side

Tags

NGSS.HS-PS1-7

Which of the following chemical equation is correctly balanced?

• Mg + O₂ → MgO

• 2Mg + O₂ → MgO

• Mg + O₂ → 2MgO

• 2Mg + O₂ → 2MgO

Tags

NGSS.HS-PS1-7

Which of the following is the balanced chemical equation that would represent the reaction between solid zinc metal and copper (II) nitrate?

• Cu(s) + Zn(NO₃)₂ (aq) → Cu(NO₃)₂ (aq) + Zn(s)

• Zn(s) + Cu(NO₃)₂ (aq) → Zn(NO₃)₂ (aq)

• Zn(s) + Cu(NO₃)₂ (aq) → ZnCu + NO₃

• Cu(NO₃)₂ (aq) + Zn(s )→ Cu(s) + Zn(NO₃)₂ (aq)

Tags

NGSS.HS-PS1-7

__Pb(NO₃)₂ + __NaI --> __NaNO₃ + __PbI₂

Which of the following sets of coefficients correctly balances the above chemical equation?

• 1:2:1:2

• 2:1:2:2

• 1:2:2:1

• 1:1:1:1

Tags

NGSS.HS-PS1-7

When the equation ____Fe₂O₃ + ____H₂ → ____Fe + ____H₂O is balanced using whole- number coefficients H₂ has a coefficient of :

• 6

• 3

• 2

• 1

Tags

NGSS.MS-PS1-5

3Ca + 2AlCl₃ --> 3CaCl₂ + 2Al

• Synthesis
• Decomposition
• Single diplacement
• Double displacement

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Identify the type of reaction:  
Ca + O --> CaO

• Decomposition
• Synthesis
• Double Replacement
• Combustion

Tags

NGSS.HS-PS1-1

NO₂ --> N₂ + O₂

• Synthesis (combination)
• Decomposition
• Single replacement
• Combustion