Examples of Physical, Chemical and Nuclear Changes

Water is boiled and turns to vapor. The vapor is cooled and changes back into water. Which best describes what has occurred?

• a physical change, because the matter changed its state
• a chemical change, because the matter changed its state
• a physical change, because a new substance was formed
• a chemical change, because a new substance was formed

Which of the following is an example of a chemical change?

• clouds forming
• water freezing
• sugar dissolving
• a candle burning

Water is boiled and water vapor forms. Which best describes this process?

• A chemical change occurs because a completely new substance forms.
• A chemical change occurs because the temperature of the water changes.
• A physical change occurs because the water disappears as it is absorbed by air.
• A physical change occurs because water and vapor are different states of the same substance.

Over time, iron becomes rust when it combines with water and oxygen. Which type of change must occur for rust to form?

• chemical
• physical
• nuclear
• mechanical

A family built a wood fire in the fireplace. The next day, they noticed that there was no wood left in the fireplace, only ashes. Which best explains this?

• Wood is separated from ashes as it burns.
• Wood becomes a new substance as it burns.
• Ashes have the same properties as wood.
• Ashes are the same substance as wood.

Which example best describes a physical change?

• iron rusting
• charcoal burning
• an ice cube melting
• a marshmallow burning

Which is the best example of a change that can be undone?

• clay put in an oven to harden
• cake batter put in an oven to bake
• chocolate left in a warm car to melt
• a bike getting rusty after getting left in the rain

Which change would result in a new substance being formed?

• sugar dissolving in water
• a glass bottle breaking
• ice melting in a bowl
• a metal can rusting

Which best demonstrates a physical change?

• lighting a match
• chalk dissolving in an acid
• plastic melting into a liquid  
• the color of metal changing when it reacts with oxygen

Which action causes a chemical change?

• leaves dropping from a tree
• leaves blowing in the wind
• leaves being burned in a fire
• leaves being crushed into pieces