WorksheetsMolecular changes
Total questions: 20
Worksheet time: 3mins
Which are 2 signs that a chemical reaction has happened? (check 2)
a powdery precipitate forms
the pieces get smaller
fire is created
Which two of the following molecules are hydrocarbons?
carbon dioxide
methane
ethanol
butene
How does fuel oil compare to petrol?
Select two statements.
Fuel oil has a higher boiling point than petrol.
Fuel oil has a lower boiling point than petrol.
Fuel oil contains larger hydrocarbon molecules than petrol.
Fuel oil contains smaller hydrocarbon molecules than petrol.
Which 2 are examples of a chemical changes? (check 2 )
ice melting
sodium and chlorine combining to make sodium chloride (salt)
paper being cut into smaller pieces
wood burning
What variable comes after the word IF
independent variable
dependent variable
Which of the following is a correct description for solids?
closely arranged and in fixed positions
closely arranged and vibrate in fixed positions
closely arranged and can move around
Which is the coefficient that counts the total number of water molecules?
3
2
What is an example of a chemical change that happens inside your body?
Food being broken down by enzymes in your stomach
Food being broken into small pieces by your teeth
Food being moved from your esophagus into your stomach
Water being absorbed inside your large intestine
Examine the image and select the best choice.
Molecular energy was increased and the substance evaporated.
Molecular energy was lost and the substance froze.
Molecular energy was lost and the substance boiled.
Molecular energy was increased and the substance melted.
What does it mean when there is a physical change?
Matter has changed from one substance into another.
Matter has changed on the molecular level.
A new substance has been formed.
Matter has changed size, shape, or form.
Which of the following is an example of a physical change?
Water freezing into ice.
A piece of wood burning.
A toy car rusting.
Zinc producing hydrogen gas when mixed with water.
What happens when sodium undergoes a chemical reaction with chlorine?
The two substances form a heterogenous mixture
The two substances form a homogenous mixture
A new compound is formed -- salt
The two substances undergo various physical changes
Examine the image and select the best choice.
Molecular energy was increased and the substance evaporated.
Molecular energy was lost and the substance froze.
Molecular energy was lost and the substance boiled.
Molecular energy was increased and the substance melted.
The boiling point of hydrocarbons . . .
increases with increasing molecular size.
decreases with increasing molecular size.
is not affected by molecular size.
A phase change in which gaseous substance changes into solid without passing through the liquid state
Condensation
Evaporation
Deposition
Solidification
On very warm days, Abby noticed that a metal door fits tightly in its frame and is tough to open. On very cold days, however, Abby noticed the door opens easily. Which choice best explains these differences.
changing temperatures cause atoms in the metal to become larger or smaller
cold temperatures cause atoms in the metal to merge together and warm daily temperatures cause atoms in the metal to split apart and become gas
temperature differences effect the molecular energy of atoms in the metal and they 'slow down' and move closer together or 'speed up' and move farther apart
the door freezes on cold days and is opens freely on warm days
The liquid nitrogen inside the cup makes the temperature of the cup so cold that oxygen in air forms as droplets on the outside of the cup. The oxygen that formed as liquid is an example of:
vaporization
freezing
condensation
melting
Which is the correct count of the atoms in a carbon dioxide molecule?.
2 Carbon + 2 Oxygen
1 Carbon + 2 Oxygen
1 Carbon + 1 Oxygen
Which of the following is TRUE about boiling?
It is slower than evaporation.
It takes place at a specific temperature.
It is the same for all liquids at the same temperature.
It takes place when bubbles begin to appear in the liquid.
Examine the image. Arrow D shows the process of . . .
melting
deposition
freezing
vaporization
sublimation
