Bubbles and fizzing can be seen instantly when baking soda is mixed with vinegar. The bubbles are evidence of which of the following?
A granular substance is added to a liquid. Which of the following would provide evidence to suggest a chemical change has taken place?
When two substances are mixed, they might form a new substance. Which of the following would indicate that a new substance has been formed?
A student mixes two clear liquids together. After a few minutes, a white powder can be seen settling on the bottom of the test tube. Which of the following is a conclusion that the student can draw based on these observations? The two clear liquids -
Which of the following characteristics is shared by all chemical reactions?
A student added white crystals to a clear liquid. The crystals dissolved in the liquid. After a few seconds, the liquid became quite warm and then turned bright red in color. The first indication that a chemical change was taking place could be observed when -
All of the following are evidence of a chemical change EXCEPT -
If we have any substance, it can be concluded that a chemical change has happened if -
Which of the following situations provides evidence that a chemical change has taken place?
Which of the following would indicate the formation of a new substance?
Four substances were mixed with a clear liquid. The observations are recorded in the following table. Based on the observations, for which mixture is there best evidence that a new substance was formed?
A student notices that sugar, when heated over a flame, turns black. How does the student know that a new substance is being formed?