The pre-1983 penny was made of an alloy of copper and zinc. An alloy is “a substance that has metal characteristics and consists of two or more different elements”. (Coordinated Science, pg.1005) Our objective is to find the metal used inside a post-1983 penny. The accepted value of the density of a post-1983 penny is 7.05g/cm3. “Density is the mass per unit volume of a material”.
It was made of pure copper and was heavy! Another interesting fact about the first pennies was that they were designed and minted by a variety of private mints. This resulted in the variations of their design, weight and diameter. In 1792, the US Congress created the US Mint and the US finally had uniform currency. The first penny created by the US Mint was still made of 100% copper, over an inch in diameter, and its design had an image of a woman with long, flowing hair - Lady Liberty.
During a find in 1885, a block of coal was broken apart to reveal a metal cube that was assumed to be shaped by the hands of a human. During the early 1900s, employees at an electric plant tore open a massive piece of coal, which to their surprise, an iron pot was uncovered. Further complicating things, a nail was found embedded deep within a block of sandstone that dated back to the Mesozoic Era. How is this? When researching the birth of the battery, textbooks will credit Count Alassandro Volta with the creation of the electric battery, which was invented in 1800.
Conclusion 10 Grams of Potassium chlorate when decomposed produces 3.915576 grams oxygen gas and 6.083363 grams potassium chloride Atomic Weight of Magnesium Introduction In this lab we will determine the atomic weight of magnesium by measuring the amount of hydrogen gas evolved when hydrochloric acid reacts with magnesium. The reaction is as follows: Mg + 2HCl -> H2 + Mg2+ (aq) + 2Cl- (aq) There is a one to one relationship between the number of moles of hydrogen gas evolved and the
How many half-lives have passed since the crystal formed? A) 1 B) more than 1 but less than 2 C) more than 2 but less than 3 D) more than 3 Answer: B 4) Which of the following geologic observations would NOT bear directly on working out the sequence of geologic events in an area? A) inclusions of sandstone in a granite pluton B) a well-exposed dike of basalt in sandstone C) an unconformity between a granite and sandstone D) the feldspar and quartz contents of a granite Answer: D 5) The principle of ________ is the concept that ancient life forms evolved in a definite order and therefore their fossils can help determine the geologic ages of strata. A) superposition B) cross-cutting relationships C) fossil succession D) fossil assemblage Answer: C 6) Which of the following is an essential characteristic of an index fossil? A) The organism lived in a very specific environment or two, such as tropical volcanic islands.
Monument 1 was found in the city of La Ventain in the year of 1945; this colossal head was 7.9 feet in height and weighed about 24 tons. Exactly seventeen Olmec Colossal Heads have been discovered: ten at San Lorenzo, four at La Venta, two at Tres Zapotes and one at La Cobata. Six of the basalt heads weighs up to forty tons. Because La Venta was believed to be a city in the middle of a swap, The Olmecs had to travel more than fifty miles to collect the large stones. Exactly how they moved the rocks are unknown.
The table below shows the displacement reactions of some metals with the aqueous solutions of their salts a. Complete the table below b. Write a worded equation for any one reaction |Metal ion solution |Iron (III) nitrate |Magnesium nitrate |Copper (II) sulphate |Zinc sulphate |Lead (II) nitrate
Percent Copper and Formula Weight of a Copper Compound Introduction: In many chemistry problems, you are asked to calculate the percent composition of each element in a compound. In this experiment a variation of this basic calculation will be employed. The amount of copper in a compound will be determined by dissolving the unknown compound in water. The copper ions in solution will be converted to metallic copper by reaction with magnesium metal. To ensure that all of the copper is removed from solution, an excess of magnesium will be used.
The first example is calculating empirical formulas from percent compositions using the percents of the different elements. Empirical formulas of compounds are also determined through quantitative analysis by using the masses of each element in the equation3. Lastly, this experiment uses the method of finding empirical formulas through combustion analysis. The empirical formula of magnesium oxide is found from the combustion of magnesium1. The four chemical equations that result when metal magnesium is heated in a closed crucible that becomes gradually exposed to the oxygen in the air are shown in table
By about 2700 BP, only seven metals were known: gold, copper, silver, lead, tin, iron and mercury. Some, such as gold could be found as uncombined or native metals while others, such as tin, were produced by smelting their ores. Copper and iron were known as both native and smelted. Archaeologists believe that metallurgy began in the Middle East about 10000 BP and that the technologies for metal extraction and production of metal alloys developed in that region and gradually spread towards Europe and Asia. The major points in this history are listed below.