What are two solid structures that expand and contract

Phosphorous acid, h3po3(aq) , is a diprotic oxyacid that is an important compound in industry and agriculture. the values of phosphorous acid are 1.30 6.70 calculate the ph for each of the given points in the titration of 50.0 ml of 1.5 m h3po3(aq) with 1.5 m koh(aq) .

A5.00 g of a in . g of at aa 5.00 g of b in . g of .?at .

What is the relative mass of an electron? a) 1/1840 the mass of a neutron + proton b) 1/1840 the mass of an alpha particle c) 1/1840 the mass of a c-12 atom d) 1/1840 the mass of a hydrogen atom