Henry mixed salt and water together in a cup until he observed a clear solution. He measured the mass of the solution. Then he placed the cup outside for several sunny days during the summer. After a week, he observed that only solid salt remained in the cup and the mass had decreased. Henry concluded that a physical and chemical change occurred in this investigation. Which statements correctly defend or dispute his conclusion?Which statement best describes a physical change?

Which of the following elements is a representative element? a. chromium (cr) b. aluminum (al) c. mercury (hg) d. silver (ag)

Mrs. smith ordered a root beer float (vanilla ice cream + root beer). mrs. smith noticed that the three states of matter (solid, liquid, and gas) all existed simultaneously in her root beer float. a. identify each phase of matter in the root beer float. b. describe the particles of all three phases of matter in the root beer float. (how are the particles arranged and moving? ) c. identify one phase change you would see in a root beer float and described what causes this change.

Used the balanced equation 2h2+ o2 - -> 2h2o. if you have 7.2 grams of o2 , how many grams of h2o can you produce ?