Chemical Reactions Quiz 2

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

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

Is burning wood a chemical or physical change?

• chemical
• physical

Which of the following is NOT an example of a physical change?

• crumpled paper
• pencil sharpening
• shrunken clothing
• sour milk

Four students performed four different investigations by combining different substances. Their results are shown in the table provided. In which experiment are new substances being formed?

• Experiment 1
• Experiment 2
• Experiment 3
• Experiment 4

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
• A solid block of ice is heated and it completely melts into a liquid. 
• Sugar that is burned gives off an odor and turns brown and then black.
• A tomato is placed into a blender and chopped up into smaller pieces.

Evidence of a chemical reactions is anything that shows - 

• a new substance has formed
• a solid dissolved in a liquid
• interaction between 2 gases
• a change in the state of matter

What is the definition for Avogadro's number?

• number of grams per one mole of a substance
• whole number ratio that is a multiple of a chemical formula
• simplest, whole number ratio of a chemical formula
• 6.02 x 10^23 particles per one mole of a substance

What is the molar mass of AuCl₃?

• 96 g
• 130 g
• 232.5 g
• 303.3 g

What is the mass of 2.50 mol of oxygen gas O₂?

• 40 g
• 80 g
• 16 g
• 32 g

What is a reactant?

• The chemical substances that begin the reaction.
• What comes from the reaction.