- In a chemical reaction, a new substance is created that is difficult to change back into its original ingredients. An example of this process is
Your answer:
chopping wood.
boiling water.
beating an egg.
baking a cake.
- Fuel cells combine hydrogen and oxygen to produce energy. What by-product would a fuel cell car produce?
Your answer:
vinegar
sulfuric acid
water
ammonia
- The total amount of matter is always conserved in a mixture. Why, then, might a mixture weigh less after a new substance is added to it?
Your answer:
This could never happen.
The new substance floated on the other substances.
Some of the ingredients were changed into gas.
Some of the ingredients were changed into a solid.
- When acids and bases are mixed, a chemical reaction occurs. Which of the following would you expect to react with baking soda (a base)?
Your answer:
pure water
baking powder
air
vinegar
- Chemistry plays an important role in the human body. Which of the following demonstrates this?
Your answer:
the production of sugars through the process of photosynthesis
the digestion of food
the division of cells to form new tissues
combustion
- In a solution, a solid or gaseous substance dissolved in a fluid is called a solute. Which of the following could be a solute in water?
Your answer:
wood
sand
oil
sugar
- The process of oxidation occurs when oxygen reacts with another substance. Which of the following is an example of oxidation?
Your answer:
photosynthesis
the reaction of water with sodium
rusting
the reaction of vinegar with baking soda
- Litmus paper turns red when dipped in an acid, and blue in a base. What color would your stomach juices turn litmus paper?
Your answer:
red
purple
blue, then red, then blue again
blue
- Chemical reactions involve chemical changes. Which of the following is always a sign that a chemical reaction has taken place?
Your answer:
a new substance
no change
a change in size
a higher temperature
- Two solids combine and instantly change into a rapidly expanding gas. This chemical reaction would describe
Your answer:
evaporation.
an implosion.
an explosion.
oxidation.