During the change process of substances, other new substances are formed.

During the change process of matter, there is no change in the formation of other new matter.

The properties of matter manifested in chemical changes.

Properties that a substance can exhibit without chemical changes.

physical properties

chemical properties

Before experiment

The flame is divided into three layers (outer flame, inner flame, and flame core)

water and carbon dioxide H₂O and CO₂

Water: Place a dry, cold beaker over the flame. If water droplets form on the wall of the beaker, it means water is produced.

Carbon dioxide: The gas is passed into clear lime water, if the stone Gray water becomes turbid, indicating that the gas is carbon dioxide.

When the candle is extinguished, white smoke will be generated. If the white smoke is lit, the candle will re-ignite.

White smoke: small solid particles of paraffin

After the experiment

Drainage collection

Experimental operation: collecting gas into a container containing air and exhaled gas In each bottle, add the same number of drops of clear lime water and shake.

Experimental phenomenon: ①The clear lime water in the gas collecting bottle containing exhaled gas becomes turbid. ② There is no obvious change in the clarified lime water in the air collecting bottle.

Experimental conclusion: The carbon dioxide content in exhaled air is higher than the carbon dioxide content in inhaled air.

Experimental operation: Insert the burning small wooden sticks into the gas collecting bottles containing air and exhaled gas respectively.

Experimental phenomenon: ①The burning wood stick is quickly extinguished in the exhaled gas. ②There is no obvious change in the air.

Experimental conclusion: The oxygen content in exhaled air is lower than the oxygen content in inhaled air

Oxygen supports combustion

Experimental operation: Breathe into a dry piece of glass. And compare it with another piece of glass placed in the air.

Experimental phenomenon: ① The exhaled gas causes small droplets to appear on the dry glass piece. ②There is no obvious change in the glass pieces in the air.

Experimental conclusion: The water vapor content in exhaled air is higher than the water vapor content in inhaled air.

narrow mouth bottle

wide mouth bottle

Gas bottle

Reagent dropper bottle

direct heating instrument

Does not heat the instrument directly

key

tweezers

Rubber tip dropper

measuring cylinder

pallet balance

The mouth of the heated solid test tube tilts upward

There is water on the outer wall of the test tube

No preheating before heating

Immediately after heating ends, it is cooled