A change from one state of matter to another involves the transfer of

a. heat.

b. atoms.

c. phases.

d. density.

The path that an object is moving or facing

Potassium (K) has an atomic number of 19. It often forms an ion by losing 1 electron. How many electrons would the ion have?

An engineering team designs a rocket that flies faster and requires less fuel than other rockets. However the rockets. However, the rocket explodes the first time it is launched.

Cesium-137 has a half-life of 30 years. You find a sample with 3 g of cesium-137. How much cesium-137 existed in the sample 90 years ago?

What is the number of moles of 500 liters of He gas at STP? A) 0.2 mol B) 90 mol C) 0.05 mol D) 22 mol

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?