Which of these is an example of a physical change?

a banana ripening in the air

hydrogen burning in the air

zinc reacting with an acid

liquid water turning into vapor

How do you think the bonds between carbon atoms might be different in diamond and graphite?

Calculate the mass of 1.00*1024 (a septillion) molecules of water.

Which of the following is true for a cell that has DNA present inside a nucleus? A: It must be a part of the oldest known fossils B: It must be a part of a eukaryote C: It must be a part of a bacterium D: It has a nucleoid

Why is distilled water added to the crucible after igniting the magnesium metal?

Are these exo/endothermic 1) combustion of gas in a car 2) water condensing on a mirror 3) boiling water

Amber has developed a line of organic lotions and handmade soaps with unique, herb-based scents and a touch of bee balm. She plans to sell these products to the wealthy residents of a nearby resort town.

Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound? a. It has the formula XZ2 b.

Are protons positive and neutrons neutral

Why might it be useful to determine the elements that a planet or moon is made up of?

Which of these is an example of a solution A Sand stirred in water B Sugar stirred in tea C A glass of water with ice in it D Oil and vinegar in a salad dressing jar