TIMSS - CHEM 3 - Chemical Change

Which of the following characteristics is shared by all chemical reactions?

• Produce a precipitate
• Show a color change
• Release heat energy
• Form new substances

A granular substance is added to a liquid. Which of the following would provide evidence to suggest a chemical change has taken place?

• The liquid gives off heat.
• The granules dissolve completely.
• The volume of the liquid increases.
• The granules seem to get smaller.

The Best Friend's Club uses "invisible ink" to write notes to each other. The invisible ink is actually lemon juice that is clear when it dries on paper, but turns brown when a club member holds a burning candle under the paper. Once it is heated, it is never invisible again.
 What type of change is occurring when the paper is heated?

• chemical change
• elemental change
• physical change
• temperature change

Which of the following characteristics is shared by all chemical reactions?

• Produce a precipitate
• Show a color change
• Release heat energy
• Form new substances

what is the definition of chemical change?

• any change that results in the formation of new chemical substances. 
• changing clothes
• matter cannot be created or destroyed, only change form
• changes affecting the form of a chemical substance, but not its chemical composition.

How do you test for Hydrogen gas?

• a) Lime water goes milky/cloudy
• b) Relights a glowing splint
• c) Lighted splint gives a squeaky pop.
• d) Bleaches damp indicator paper.

What does the formula HCl stand for

• Hydrogen, carbon and Iodine
• Hydrochloric acid 
• Helium chloride
• Carbon nitrate 

Which is a chemical reaction

• A banana ripped

• ice melting

• pencil breaking

• paper burning

What happens in ALL chemical changes?

• Change in state of matter
• A new substance is formed
• Bubbles are produced
• An explosion

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same

• that matter can only be changed into new substances by introducing a catalyst

• that matter exists in the same state throughout any chemical change

• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants