Chemical Reactions Introduction

Choose the most correct sentence to describe the following reaction: Fe + O₂ --> Fe₂O₃

• An iron solution forms oxygen gas and solid iron oxide.

• iron and oxygen react to form iron oxide.

• Solid iron and oxygen make iron oxide.

• Iron and dioxygen gas produce solid iron(II) oxide.

Choose the most correct sentence to describe the following reaction:

Al₂O₃ + heat --> Al + O₂

• When heated Aluminum oxide yields aluminum and oxygen.

• Aluminum reacts with dioxygen to make aluminum oxide.

• Solid aluminum(II) oxygen make gas aluminum and oxygen.

• Solid aluminum oxide produces aluminum oxifde and oxygen gas

Choose the most correct sentence to describe the following reaction: NH₃ + O₂ --> NO + H₂O

• Ammonia and hydrogen form nitrogen and water

• Ammonia and oxygen react to yield nitrogen oxide and water

• Ammonia and oxygen produce nitrogen oxide and water when mixed.

• Ammonia and oxygen react to make nitrogen oxide and carbon dioxide

Fill in the blank: NH₃+ O₂ --> NO + H₂O translates into "Nitrogen trihydride and oxygen ___________ nitrogen oxide and water. ( more than one answer)

• react to make

• yields

• produces

• gives

Fill in the blank with an appropriate word or phrase: N₂O₃ + H₂O --> HNO₂ translates into "Dinitrogen trihydride and water ___________hydrogen nitrite.

Choose the most correct sentence to describe the following reaction: Fe + O₂ --> Fe₂O₃

• iron forms oxygen and iron oxide.

• iron and oxygen yields iron oxide

• iron and hydrogen yields iron oxide.

• Iron and oxygen react to form oxygen + iron

Evidence of a chemical reactions is anything that shows - 

• a new substance has formed
• a solid dissolved in a liquid
• interaction between 2 gases
• a change in the state of matter

Which of the following is a chemical change?

• water freezes to form ice

• sugar dissolves in water

• wood burns in a campfire

• a piece of metal expands when heated

Which of the following is a chemical reaction?

• Water freezes.
• Sugar dissolves in water.
• Salt and pepper are mixed in a dish.
• Iron rusts.

When two substances were combined, bubbles were produced and the temperature dropped.  This most likely means that:

• a chemical reaction took place
• the two substances had low boiling points
• one substance dissolved in the other
• the two substances are non-reactive