Which of the following is a chemical change?

A - formation of a solid from two liquids

B - phase change

C - change in surface area

D - volume change

Give 4 Economics activities associated with water

A 12.2-g sample of X reacts with a sample of Y to form 78.9g of XY. what mass of Y reacted?

For the exothermic reaction N2 (g) + 3H2 (g) →2nh3 (g) what will happen if hydrogen gas was removed from the reaction mixture?

Consider the following generic chemical reaction: 2A+3B→3C How many moles of B are required to completely react with: 8 mol of A, 9 mol of A, 3 mol of A, and 10 mol of A?

A miner working 260m below sea level opened a carbonated soft drink during a lunch break. To his surprise, the soft drink tasted rather "flat." Shortly afterward, the miner took an elevator to the surface.

Compare the densities among the three states of matter (which is highest, lowest?)

Epsom salts (magnesium sulfate) have a solubility of 26.2 grams. If you dissolved 26.0 grams of Epsom salts in 100 g of water at 20 degrees Celsius, what type of solution would this be?

An airplane model is an example of what type of model

A radioactive isotope has a half-life of 2.5 years. Which fraction of the original mass remains unchanged after 10 years?

The air exhaled from the lungs of a smoker has a concentration of 24 ppm CO. Express the concentration as a percent.