Which statement explains why a rock does not sink in a lake that is frozen over? 1. Particles are much harder in a solid than in a liquid.

2. Particles are much closer together in a solid than in a liquid.

3. Particles in a solid are moving too fast for anything to penetrate them.

4. Particles in a solid are fixed in place.

(will get brainliest)

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ