Answer the following question given this paragraph: Dilution of the products with water, followed by filtration to remove calcium sulfate, gives a dilute acid solution contaminated with calcium dihydrogen phosphate, Ca(H2PO4)2, and other compounds associated with calcium phosphate rock. It is possible to prepare pure orthophosphoric acid by dissolving P4O10 in water. The action of water on P4O6, PCl3, PBr3, or PI3 forms phosphorous acid, H3PO3 (shown in Figure 18.53). The best method for preparing pure phosphorous acid is by hydrolyzing phosphorus trichloride: PCl 3(l) + 3H 2 O(l) H 3 PO 3(aq) + 3HCl(g) Heating the resulting solution expels the hydrogen chloride and leads to the evaporation of water. When sufficient water evaporates, white crystals of phosphorous acid will appear upon cooling. The crystals are deliquescent, very soluble in water, and have an odor like that of garlic. The solid melts at 70.1 C and decomposes at about 200 C by disproportionation into phosphine and orthophosphoric acid: 4H 3 PO 3(l) PH 3(g) + 3H 3 PO 4(l). Q: The best method for preparing pure phosphorous acid is by hydrolyzing what? Choices: - dioxide trichloride - carbon trichloride - dioxide phosphat - phosphorus trichloride A:
phosphorus trichloride
Answer the following question given this paragraph: Physical and chemical properties of geometric isomers are generally different. While cis -2-butene is a polar molecule, trans -2-butene is nonpolar. Heat or irradiation with light can be used to bring about the conversion of one geometric isomer to another. The input of energy must be large enough to break the pi bond between the two carbon atoms, which is weaker than the sigma bond. At that point, the now single bond is free to rotate and the isomers can interconvert. Q: Physical and chemical properties of geometric isomers are generally what? Choices: - round - difficult - similar - different A:
different
Q: Answer the following question given this paragraph: Plants in the diploid generation are called sporophytes . They form from the fertilization of gametes. They reproduce asexually. They have a structure called a sporangium that produces haploid spores by meiosis. Spores develop into the haploid generation. Then the cycle repeats. Q: What are plants in the diploid generation called? Choices: - keratinocytes - haplocytes - monocots - sporophytes A:
A: sporophytes
Question: Answer the following question given this paragraph: The focus is where the rocks rupture. The epicenter is the point on the ground directly above the focus. Q: What is the point on the ground that is located directly above where underground rocks fracture (or the "focus" point)? Choices: - danger zone - fault line - seismic point - epicenter A:
Answer: epicenter
*Question*
Answer the following question given this paragraph: You may be able to avoid some of the health effects of outdoor air pollution by staying indoors on high-pollution days. However, some indoor air is just as polluted as outdoor air. Q: What are some uses of chlorine gas? Choices: - washing hands - fueling airplanes - rooting plant cuttings - cleaning, disinfecting and in swimming pools A:
**Answer**
cleaning, disinfecting and in swimming pools
Q: Answer the following question given this paragraph: Shield volcanoes often form along divergent plate boundaries. They also form at hot spots, like Hawaii. Shield volcano eruptions are non-explosive. Q: Shield volcanoes often form along which locations? Choices: - convergent boundaries - tectonic plates - fault lines - divergent plate boundaries A:
A: divergent plate boundaries