3. Determine the pH value for calcium hydroxide, Ca(OH), with concentration of 0.05 mol dm3. [pH + pOH = 14).

Acrystal that absorvd water from air is (blank)a. aqueousb. homogenousc. hygroscopicd. efflorescent

Asample of hydrated tin (ii) chloride (sncl2) has a mass of 4.90 g. when it is dehydrated, it has a mass of 4.10 g. which is the correct chemical formula for the hydrate? sncl2•2h2o          sncl2•4h2o          sncl2•6h2o

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.