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-PS1-1

NGSS.HS-PS1-2

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 answer choices below correctly shows the products of the double replacement reaction shown below? BaCl₂ + Na₂SO₄ → ______ + _______

• BaSO₄ + NaCl

• Cl₂Ba + SO₄Na₂

• Cl₂SO₄ + BaNa₂

• BaCl₂ + Na₂SO₄

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which type of reaction is:

C₇H₁₆ + 10 O₂ → 7 CO₂ + 8 H₂O

• Synthesis
• Decomposition
• Single Displacement
• Combustion

Which type of reaction is:

3 Pb + 2 H₃PO₄ → 3 H₂ + Pb₃(PO₄)₂

• Synthesis
• Single Displacement
• Double Displacement
• Combustion

Which type of reaction is:

2 H₃AsO₄ → As₂O₅ + 3 H₂O

• Synthesis
• Decomposition
• Single Displacement
• Combustion

Which type of reaction is: C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O

• Synthesis
• Decomposition
• Single Displacement
• Combustion

Which type of reaction is:

2 NaBr + Ca(OH)₂ → CaBr₂ + 2 NaOH

• Synthesis
• Single Displacement
• Double Displacement
• Combustion

Balance the following:

____ Fe + ____ Cl₂ → ____ FeCl₃

• 1,1,2
• 1,3,1
• 2,2,3
• 2,3,2