Problem: The X-ray crystal density method is primarily a method for determining the Avogadro constant NA but as the Avogadro constant is related to the Planck constant it also determines a value for h. The principle behind the method is to determine NA as the ratio between the volume of the unit cell of a crystal, measured by X-ray crystallography, and the molar volume of the substance. Crystals of silicon are used, as they are available in high quality and purity by the technology developed for the semiconductor industry. The unit cell volume is calculated from the spacing between two crystal planes referred to as d220. The molar volume Vm(Si) requires a knowledge of the density of the crystal and the atomic weight of the silicon used. The Planck constant is given by
What element is used typically to establish Avogadro's constant?
The answer is the following: Crystals of silicon

Problem: The country was controlled by a revolutionary council until 1984. The first multi-party elections were held in 1994. An army uprising in May 1998 led to the Guinea-Bissau Civil War and the president's ousting in June 1999. Elections were held again in 2000, and Kumba Iala was elected president.
When were the first multi-party elections held?
The answer is the following: 1994

Problem: The majority of Freemasonry considers the Liberal (Continental) strand to be Irregular, and thus withhold recognition. For the Continental lodges, however, having a different approach to Freemasonry was not a reason for severing masonic ties. In 1961, an umbrella organisation, Centre de Liaison et d'Information des Puissances maconniques Signataires de l'Appel de Strasbourg (CLIPSAS) was set up, which today provides a forum for most of these Grand Lodges and Grand Orients worldwide. Included in the list of over 70 Grand Lodges and Grand Orients are representatives of all three of the above categories, including mixed and women's organisations. The United Grand Lodge of England does not communicate with any of these jurisdictions, and expects its allies to follow suit. This creates the distinction between Anglo-American and Continental Freemasonry.
How many Grand Lodges and Grand Orients are listed in the CLIPSAS list?
The answer is the following: 70

Problem: Present-day statutes from across the nation use the same words and phrases, requiring modern executions to take place within a wall or enclosure to exclude public view. Connecticut General Statute 54100 requires death sentences to be conducted in an "enclosure" which "shall be so constructed as to exclude public view." Kentucky Revised Statute 431.220 and Missouri Revised Statute 546.730 contain substantially identical language. New Mexico's former death penalty, since repealed, see N.M. Stat. 31-14-12, required executions be conducted in a "room or place enclosed from public view." Similarly, a dormant Massachusetts law, see Mass. Gen. Law ch. 279 60, required executions to take place "within an enclosure or building." North Carolina General Statute 15-188 requires death sentences to be executed "within the walls" of the penitentiary, as do Oklahoma Statute Title 22 1015 and Montana Code 46-19-103. Ohio Revised Code 2949.22 requires that "[t]he enclosure shall exclude public view." Similarly, Tennessee Code 40-23-116 requires "an enclosure" for "strict seclusion and privacy." United States Code Title 18 3596 and the Code of Federal Regulations 28 CFR 26.4 limit the witnesses permitted at federal executions.
What state's law requires that capital punishment occur "within the walls" of a penitentiary?
The answer is the following:
North Carolina