Question: Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index. Lead oxide also facilitates solubility of other metal oxides and is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders. The high ionic radius of the Pb2+ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (108.5 vs 106.5 Ohm·cm, DC at 250 °C). For more details, see lead glass.
Is there an answer to this question: What makes the Pb2+ ion vitreous?

Answer: unanswerable


Question: From as early as 1935 Japanese military strategists had concluded the Dutch East Indies were, because of their oil reserves, of considerable importance to Japan. By 1940 they had expanded this to include Indo-China, Malaya, and the Philippines within their concept of the Greater East Asia Co-Prosperity Sphere. Japanese troop build ups in Hainan, Taiwan, and Haiphong were noted, Japanese Army officers were openly talking about an inevitable war, and Admiral Sankichi Takahashi was reported as saying a showdown with the United States was necessary.
Is there an answer to this question: What was the importance of the Dutch East Indies to Japan?

Answer: oil reserves


Question: Prior to Mendel's work, the dominant theory of heredity was one of blending inheritance, which suggested that each parent contributed fluids to the fertilisation process and that the traits of the parents blended and mixed to produce the offspring. Charles Darwin developed a theory of inheritance he termed pangenesis, which used the term gemmule to describe hypothetical particles that would mix during reproduction. Although Mendel's work was largely unrecognized after its first publication in 1866, it was 'rediscovered' in 1900 by three European scientists, Hugo de Vries, Carl Correns, and Erich von Tschermak, who claimed to have reached similar conclusions in their own research.
Is there an answer to this question: What year was Mendel's work first published?

Answer: 1866


Question: After 1937 the Lord Mayor and the state commissioners of Hanover were members of the NSDAP (Nazi party). A large Jewish population then existed in Hanover. In October 1938, 484 Hanoverian Jews of Polish origin were expelled to Poland, including the Grynszpan family. However, Poland refused to accept them, leaving them stranded at the border with thousands of other Polish-Jewish deportees, fed only intermittently by the Polish Red Cross and Jewish welfare organisations. The Gryszpan's son Herschel Grynszpan was in Paris at the time. When he learned of what was happening, he drove to the German embassy in Paris and shot the German diplomat Eduard Ernst vom Rath, who died shortly afterwards.
Is there an answer to this question: How many Hanoverian Jews were expelled in 1938?

Answer:
484