TO 1 Chemistry 8A

Which of the following is an example that includes evidence of a chemical reaction?

• A sample of zinc is placed in water and it settles to the bottom

• Sugar that is burned gives off an odor and turns brown and then black.

• A solid block of ice is heated and it completely melts into a liquid

• A tomato is placed into a blender and chopped up into smaller pieces

....... is an example of both a color change and a new substance produced from a chemical change with oxygen and metal.

• shredded paper

• wood chips

• rust (iron oxide)

• melted wax

In the laboratory, Budi put 10 ml of sulfuric acid to 10 ml of sodium hydroxide.

Which one is most likely to indicate the chemical reaction?

• A gas is given off

• Changing pH

• A precipitate formed

• Changing temperature

Galvanising is process of ...

• iron railing coated with paint

• adding calcium chloride to iron bridge

• coating metal property with plastic

• coating iron fence with zinc

An acid reacts with a metal carbonate to produce salt, water and gas. What gas is produced by that reaction?

• Carbon dioxide

• nitrogen

• hydrogen

• Oxygen

Magnesium ribbon burns in air giving white flame and powder.

Write the word equation for this reaction.

• Magnesium + oxygen --> Magnesium oxide

• Magnesium + oxygen --> Magnesium dioxide

• Magnesium --> Magnesium oxide

• Magnesium --> Magnesium dioxide

Sodium + sulfuric acid ----> _________ + _________

What are the products that can be filled to make a complete word equation above?

• Sodium + hydrogen

• Sodium chloride + hydrogen

• Sodium sulfate + hydrogen

• Sodium + oxygen

What element rusts?

• carbon

• manganese

• iron

• potassium

What metal from the list below does not corrode ?

• Iron

• Steel

• Gold

• Magnesium

Which of the following is a sign that a chemical reaction has occurred?

• change in shape
• melting
• formation of a gas
• dissolving