Answers epsom salts is a hydrate of magnesium sulfate, mgso4 • 7h2o. what is the formula of the substance that remains when epsom salts is completely dehydrated

All hydrates have some amount of water of hydration present associated with their crystal structure. When such hydrated compounds are heated, the water of hydration is driven off from the molecular arrangement. For example, epsom salt is heptahydrate of magnesium sulfate. So, when epsom salt is heated it loses the water of hydration to form anhydrous magnesium sulfate. So anhydrous magnesium sulfate would remain after heating epsom salt to remove the water of hydration.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.