Chemical Reactions - Pre-Assessment

Which of the following is a chemical change?

• Sawdust is produced from wood being cut by a power saw.

• Water freezes to form ice.

• Fireworks explode in a colourful light display.

• Juice is obtained from an orange.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Describe the particles in a solid.

• The particles in a solid are strongly bonded to each other so the solid has a definite shape.

• The particles in a solid are strongly bonded to each other so the solid does not have a definite shape.

• The particles in a solid are weakly bonded to each other so the solid has a definite shape.

• The particles in a solid are weakly bonded to each other so the solid does not have a definite shape.

Tags

NGSS.MS-PS3-4

Identify why gases are easily compressed.

• The particles can diffuse

• There is pressure between particles squashing them together

• There is great energy between the particles allowing them to change

• There is a lot of space between the particles

Tags

NGSS.MS-PS2-2

Define melting point.

• Melting point is the temperature at which a liquid changes to a gas.

• Melting point is the temperature at which a solid changes to a gas.

• Melting point is the temperature at which a liquid changes to a solid.

• Melting point is the temperature at which a solid changes to a liquid.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Recall the scientific term used to describe the process of a gas changing to a liquid.

• Evaporation

• Boiling

• Condensation

• Sublimation

Tags

NGSS.MS-PS1-4

A permanent colour change may be an indication that a chemical reaction has taken place. Identify which of the following is not an indication of a chemical reaction.

• Sugar caramelising

• Toasting bread

• A glass breaking

• Lighting a match

Tags

NGSS.MS-PS1-2

Analyse the word equation:

methane + oxygen → carbon dioxide + water + energy

This reaction shows that:

• Oxygen is a product of this reaction

• Methane burns with a sooty flame

• This is an exothermic reaction

• A constant input of energy is required to keep the reaction going

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-5

As a solid object is heated, its particles:

• Vibrate less rapidly and cause it to contract

• Vibrate more rapidly and cause it to expand

• Attract each other more, causing contraction

• Shrink in size so the gaps between them increase

Tags

NGSS.MS-PS1-4

Identify which of the following would indicate a reaction that requires an input of energy.

• A gas is given off

• The reaction glows

• A precipitate forms

• The reaction feels cold to the touch

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Joe collected some snow and placed it in a beaker. During the day it melted to produce clear water. Joe and his friends made the following comments about the process.

Joe: This is a chemical change as there is a change in colour.

Jill: The beaker is now warmer than when you collected the snow. This must be a chemical change as energy is absorbed.

Jenny: This is a physical change as the trapped air bubbles react with the snow.

Jamal: This is a physical change as no new substances are created.

Who do you believe is correct?

• Joe

• Jill

• Jenny

• Jamal

Tags

NGSS.MS-PS1-4

NGSS.MS-PS1-2