The constellations seem to move as the seasons on earth change. what causes this?

How many grams of aluminum will there be in 98g of al2o3?

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process

How much energy is required to vaporize 2 kg of copper? a 4730 kj b 207kj c 9460 kj d 414kj