Of the following, which does not signify a chemical reaction?

1) tarnish

2) release of heat

3) changing state

4) release of gas

The diagram illustrates the water cycle. Parts of the water cycle labeled U through Z. U: Water moving from a lake into the clouds. V: Clouds. W: Water falling from clouds as rain and snow. X: Water moving from ground to the clouds.

A 2.45 g sample of a gaseous oxide of nitrogen occupies a volume of 1.34 l at 28°c and 745 mmhg. What is the most likely formula for the gas?

What element has two electrons in the outer most shell

What is the ratio of Al ions to S ions in a neutral compound? 1:1 2:1 2:3 3:2

Harvey mixes two liquids. Which observation of the new mixture most likely indicates a precipitate is forming? A) a cloudy appearance B) a bubble formation C) a change in color D) a change in odor

The word atom means invisible?

A pycnometer weighs 25.60 g empty and 35.55 g when filled with water at 20°C. The density of water at 20°C is 0.9982 g/ml. When 10.20 g lead is placed in the pycnometer and the pycnometer is again filled with water at 20°C, the total mass is 44.83 g.

How does weathering affect the surface area of a rock? Explain your answer.

How would each of the following procedural errors affect the results to be expected in this experiment? Give your reasoning in each case. (A) Not all of the liquid was vaporized when the flask was removed from the water bath.

What volume of 2.00 m must be added to 150.0 ml of 1.00 m chloroacetic acid to produce a buffer solution having a ph of 3.30?