Changes in Material under the Presence or Lack of Oxygen-PEA

Why did the candle light up?

• because of oxygen

• because of combustion

• because of the fire

• because of the matches

what is needed to start a fire?

• oxygen

• carbon dioxide

• matches

• combustion

What is the role of oxygen in the process of combustion?

• it supply carbon dioxide

• it burns the candle

• it supports combustion

• it stop the fire

What is the main reason why metal rusting happen?

• it supply carbon dioxide

• it burns the candle

• it's because of the presence of oxygen in the air that reacts on metal

• it's because of the substances itself

Why did the candle light distinguish when covered by a glass?

• because of presence of oxygen

• because of lacking oxygen

• because of the fire

• because of the matches

What is the effect of oxygen on a lighted splint?

• Oxygen extinguishes a lighted splint

• Oxygen makes a lighted splint burn even more

• Oxygen extinguishes a lighted splint with a pop sound

• Oxygen does not have any effect on a lighted splint

Which gas (or gases) found in the earth atmosphere can be used for welding?

• Oxygen and argon

• Nitrogen

• nitrogen and water vapour

• water vapour