7. a rectangular block of lead (pb) measures 20.0 mm x 30.0 mm x 45.0 mm. if the density of pb is 11.34 g/cm3, calculate the mass of the block.

Enough of a monoprotic weak acid is dissolved in water to produce a 0.0172 m solution. if the ph of the resulting solution is 2.39 at 20 °c, determine the pka for the acid.

If i add water to oil what will happen

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum