Q: Which of the following is an example of a container that is filled with a pure substance rather than with a mixture?
A: a balloon filled with helium
Q: Which of these is a safe practice in a laboratory investigation when working with chemicals?
A: wearing safety goggles when working with chemicals
Q: Most stars are similar to each other in
A: composition.
Q: Some events on Earth happen instantly while others take thousands of years to occur. Which process takes the longest time to complete?
A:
weathering of a rock to form small rocks and sand