Question 4 (1 point)
Hans and Kristoff were testing powders in science class. First, they put the powder in a zip lock bag. Next, they added some water. The powder fizzed and bubbled, and soon it disappeared. When the bubbling stopped, the bag contained a clear liquid and a lot of gas.
What is the MOST OBVIOUS sign a chemical reaction took place?
a
A gas was produced.
b
The powder dissolved in the water.
c
There was a change in temperature.
d
The powder mixed with the water.
1 answer
a. A gas was produced.