The density of an object never changes when the temperature of that object changes true or false?

According to the vsepr theory what is the shape of a molecule that has a central atom valence three other items with no lone pairs of electrons

A5.000 g sample of niso4 h2o decomposed to give 2.755 g of anhydrous niso4. what is the formula of the hydrate? what is the full chemical name for the hydrate? what is the molar mass of the hydrate? niso4•_h2o what is the mass % of water in the hydrate?

The molality of calcium chloride (cacl2) in an aqueous solution is 2.46 m. what is mole fraction of the solute?