How much energy is required to heat 2kg of water through the following changes?

32p and 31p are two isotopes of phosphorus. compare the number if subatomic particles that are present in the atoms of these isotopes.

Uuestons niuthe no. of millimoles of hcl required to neutralize 10 ml of 0.2 m na2co3 is(a) 2.0 m mole(b) 4.0 m mole(c) 0.2 m mole(d) 0.4 m mole

Freya built a model of the earth, sun, and moon. freya can cause her model to move in three different ways. she can turn the crank to model how the earth revolves around the sun, she can spin the globe to model how the earth rotates on its axis, and she can push the moon with her fingers to model how the moon revolves around the earth. how could freya best use her model to demonstrate the cause of the day/night cycle on earth?