Physical and Chemical Changes

Front

Definition of physical change?

Back

A change in size, shape, state, color or appearance that does not create a new substance.

Front

Which of the following examples is a good indication that a physical change has occurred? Options: New substance was created, change in odor and color, change in size, sudden change in temperature.

Back

There is a change in the size of the object.

Front

Which of the following is an example of physical change?

• Chopping wood into smaller pieces.
• Burning wood to create ash.
• Mixing sodium and water that creates a sudden change in temperature and an explosion.
• Burning rocket fuel to move the space shuttle in orbit.

Back

Chopping wood into smaller pieces.

Front

A teacher rubbed a match against a piece of sandpaper. The match started to burn. Which statement is true?

Back

The match underwent a chemical change because it started to burn which indicates that there was a creation of a new substance.

Front

The photograph shows rockets carrying a space shuttle off the launchpad. The main source of fuel for this shuttle is liquid nitrogen and liquid hydrogen. Both are mixed and are burned together to power the main rocket engines. When the fuel ignites to create an upward motion for the shuttle, choose the correct statement that best describe the changes occurring.

Back

As the fuel burns, energy is released to create an upward motion of the shuttle. This is an example of chemical change because two chemicals react to ignition, which in return changes their composition to a new substance.

Front

Chemical change

Back

A chemical change takes place when one or more substances change to form one or more new substances.

Front

Which of the following is not an evidence of a chemical change occurring?

• New substance has formed.
• Change is size and shape.
• Change in odor
• Formation of precipitate

Back

Change is size and shape.

Front

Students conducted an investigation using two different test tubes. One student combined Magnesium (Mg) in water, while the other student combined Magnesium (Mg) in Hydrochloric Acid (HCl). The observations made for each test tube is listed in the chart below. Which of the following statements is true?

• Test Tube 1 underwent a chemical change because the temperature of the water changed when the lit match was placed.
• Test Tube 1 underwent a physical change because the temperature of the water changed while there was no other observable activity.
• Test Tube 2 underwent a chemical change because bubbling occurred, the temperature changed, and the metal strip dissolved to form a new substance.
• Test Tube 2 underwent a physical change because the size of the metal strip changed and the lit match made a popping sound as the fire is extinguished.

Back

Test Tube 2 underwent a chemical change because bubbling occurred, the temperature changed, and the metal strip dissolved to form a new substance.

Front

Which observations show that a chemical reaction occurred?

Observations 1 & 4

,

Observations 1 & 2

,

Observations 2 & 3

,

Observations 3 & 4

Back

Observations 2 & 3

Front

What evidence proves there was a chemical reaction?

Back

Formation of gas and bubbles