Which detail from Heart of Darkness shows the ineffectiveness of the colonizers. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.
Hottest Questions. Previously Viewed. Unanswered Questions. Is it possible to convert the brass penny back to copper again? Wiki User By "the" penny, I'm assuming that you mean a penny that has been treated with zinc and sodium hydroxide, and then heated over a flame. To remove the brass plating, you can create friction on the surface of the coin that wears it away, reverting it back to its original copper color.
This might be possible with a ton of vinger or lemons, and a lot a scrubing. That was a great question. That would be a great experiement to try. Asked in Metal and Alloys Does brass metal ever turn green? It can. Brass contains copper, and many copper salts are either green or blue, so it's entirely possible for a piece of brass to develop a greenish patina.
Asked in Elements and Compounds What is alloyed with copper in brass? Brass is an alloy of copper and zinc. Asked in Plumbing, Metal and Alloys What is the alloy of copper and brass? Brass is the alloy of copper and zinc.Brass is an alloy of copper Cu and zinc Zn.
Spectrophotometry is a way of analyzing the transmittance of light through a solution it can also measure the amount of light that is absorbed by the solution. It usually can work in various wavelengths of light.
We will be using a colorimeter to analyze samples in this experiment. We will set to the colorimeter to nm. Because our solution is blue, it will reflect blue light. This is represented by the following equation:. The smoke, of course, escapes from the container, leaving a Copper II Nitrate solution. We will compare this solution with other Copper nitrates of known molarity. By creating a series of standard solutions of copper Nitrate, we can find the line of best fit among the various concentrations the equation of a line.
Thus, by finding the absorbance of a solution of unknown molarity, we can use the equation to find the molarity. Pour 50 mL of water into a mL volumetric flask. Then take your blue Cu NO 3 2 solution and pour it carefully into the volumetric flask.
This ensures that you are adding acid to water. Next, pour more water in until you reach the mL line. Pipette some of this solution into a cuvette and cap it. We will now make our dilutions. These are the standard points which we will use on our graph. Start with 10 mL graduated cylinder of a 0. Fill the graduated cylinder back to 10 mL with distilled water. This creates a 0. Repeat this process until you have 0.
Fill an additional cuvette with water.The overall goal of this lab was to make a calibration curve with a plot of absorbance vs. After 5 minutes, the absorbances at nm were measured using a spectrometer. A calibration curve displaying Absorbance vs.
Density Test Questions
Concentration was created using Excel by using the increasing concentrations of the five standard solutions for the x values, and their corresponding absorbances for the y values. In Part 2, a small amount of Cola was heated in a beaker covered with a watch glass to reduce evaporation. Once cooled, a sample of the soda was diluted to fold with ultra-pure water by combining 2 mL soda and mL of ultra pure water, and then 5.
The calibration curve created in Part 1 was used to solve for the phosphate concentration in soda pop. In Part 3, the same procedure was used as in Part 2 to determine the phosphate concentration in an unknown solution. It also was not diluted because it was a water sample. When only the molybdate binds with phosphate, it turns the solution blue, indicating the presence of PO 4 The linear relationship between absorbance and concentration displays that absorbance depends on the concentration.
To calibrate the spectrometer, a solution containing 5. Since the species of interest was the phosphate, everything but the phosphate was used in the blank, and subtracted from the measured absorbance of cuvette containing a phosphate solution. The results were not quite as expected, since the data was askew due to a great amount of experimental error in Part 1 of the lab. This error occurred from not adding the correct amount of solutions to each beaker, throwing off the absorption rate and then the calibration curve.
The absorbances of each of the five solutions being wrong also affected the linear equation obtained in Part 1, which made R 2 not be as close to the expected value of 1. The linear equation being not a perfect straight line also affected the determination of concentration of phosphate in the Cola in Part 2. The impact of this experimental error in Part 1 affected the rest of the lab, not allowing for perfect results.
In this experiment, a calibration curve was created by plotting absorbance vs. The calibration curve was constructed by measuring the absorbance rate of phosphate in five standard solutions.
The linear equation derived from the calibration curve was then manipulated and used to determine the concentration of phosphate in soda pop, and in an unknown water solution.
The concentration of phosphate was experimentally determined to be 1. Article last reviewed: St. Skip to content. Type of Reactions Lab Answers. Most reacted comment. Hottest comment thread. Recent comment authors. Abel Y. Single Displacement Reactions Lab Explained.
Chemistry of Copper
It only takes seconds! Upload your Homework.Copper occupies the same family of the periodic table as silver and gold, since they each have one s-orbital electron on top of a filled electron shell which forms metallic bonds.
This similarity in electron structure makes them similar in many characteristics. All have very high thermal and electrical conductivity, and all are malleable metals. Among pure metals at room temperature, copper has the second highest electrical and thermal conductivity, after silver. The use of Copper dates back far into history. Copper beads have been found in what is now modern Iraq, dating back to BC.
The metal is relatively easy to mine and refine, contributing to its early and widespread use.
From Copper to Copper Lab
Being soft, however, it is unsuitable for making reliable tools and weapons. Early metalsmiths as far back as BC learned to combine copper with other metals to produce more durable alloys.
Brass copper and zinc and bronze copper and tin are two examples. The symbol and name for copper are from the Latin cuprumwhich literally means "from the island of Cyprus", an early source of copper ore. Before U. Now they are mostly zinc with a thin shell of copper. Most copper that is mined today is refined and drawn into wire for use in the electrical industries.
A significant portion is also used in manufacturing water pipe. Copper, of course, has a characteristic color which most people recognize. It is one of the best electrical conductors and resists corrosion from most acids except nitric and hot concentrated sulfuric. When exposed to the elements for a period of time it develops a greenish coating or patina which is copper II carbonate, a protective coating that prevents further wear.
Copper occurs both in combined state and free state and also in many ores. The copper ores are mostly found in the north of India.
The extraction of copper also involves many steps. The ore used for extraction is copper pyrites, which is crushed, concentrated and then heated in the presence of air. During heating the moisture gets expelled and the copper pyrites gets converted to ferrous sulfide and cuprous sulfide.
Blast furnace is used to heat the mixture of roasted ore, powdered coke and sand. In the blast furnace oxidation reactions takes place. Cuprous sulfide forms cuprous oxide which is partially converted to cuprous sulfide. This cuprous sulfide contains some amount of ferrous sulfide and this is called matte. Matte is removed from the base outlet of blast furnace. The removed matte is shifted into Bessemer converter which is lined inside with magnesium oxide.
The cuprous oxide formed reacts with Cu2S and forms copper. The copper thus formed is to be purified by electrolysis. Hydroxide ions from, say, sodium hydroxide solution remove hydrogen ions from the water ligands attached to the copper ion.
Once a hydrogen ion has been removed from two of the water molecules, you are left with a complex with no charge - a neutral complex. This is insoluble in water and a precipitate is formed.This is a collection of 10 chemistry test questions with answers dealing with the density of matter.
You'll find the answers to each question at the bottom of the page. What is the density of the sugar in grams per milliliter? The density of a substance is 1. What is the mass of 0. The density of pure solid copper is 8. What volume does 5 kilograms of copper occupy? What is the mass of a 15 centimeter cube of iron if the density of iron is 7.
Which of the following is greater? Two liquidsA and B, have densities 0. When both liquids are poured into a container, one liquid floats on top of the other. Which liquid is on top? How much does 1 gallon of water weigh in pounds? Liquid A. When you're asked to calculate density, make sure your final answer is given in units of mass such as grams, ounces, pounds, kilograms per volume cubic centimeters, liters, gallons, milliliters. You may be asked to give an answer in different units than you're given.
It's a good idea to be familiar with how to perform unit conversions when working on these problems. The other thing to watch is the number of significant figures in your answer. The number of significant figures will be the same as the number in your least precise value.
So, if you have four significant digits for mass but only three significant digits for volume, your density should be reported using three significant figures.
Finally, check to make sure your answer is reasonable. One way to do this is to mentally compare your answer against the density of water 1 gram per cubic centimeter. Light substances would float on water, so their density should be less than that of water.Introduction Chemistry is the science of matter, especially its chemical reactions.The Copper Cycle
These reactions are performed between elements on the periodic table. All of the elements on the periodic table have unique properties, structures and abilities. Chemical reactions are often accompanied by formation of a precipitate, evolution of gas, change I colour, or pronounced temperature change.
In this activity, you will observe these characteristics of chemical reactions. Each element, when bonded with another element will create a unique and new third, fourth or maybe even fifth substance s! This is because of the special properties that each element has to offer.
Now, in regards to the lab at hand, this reaction is far different from the reactions that we have performed; but it does show that each element has a unique quality about it, and when combined with another element can create something entirely new.
We will see different types of chemical reactions taking place throughout this cycle where we would start from Copper and would go through five chemical reactions and end up with copper. Question What type of chemical reaction is involved in each step of this investigation? The first product in the reaction is a single displacement of the two reactants, and the other two products are decomposed from the second reactant in the reaction.
Reaction C will have a decomposition reaction which follows the. Observations Reaction A Starting to bubble on hot plate Turns blue colour, when boiling Copper metal expands to spherical-like balls moving fast on surface of solution Amount of solution decreases after boiling Copper balls dissolved after two minutes Distilled water added to make Reaction B When acid added, immediate blue precipitate forms After 37 drops of solution, the solutions turns basic red litmus to blue Reaction C Solutions gradually turned darker after 30 seconds of stirring After 8 minutes of the solution getting darker, a black precipitate is formed.
Reaction D When acid added, it dissolved the black precipitate turned into clumps Clear blue liquid was left Reaction E When Zinc added it formed copper metal and was very thin and floating on the surface Yellowish Colour of the Solution on the surface Partly Cloudy When acid added the solution turned clear and only copper metal is left. Analysis 1. The type of reaction that occurs through reaction A through E is a chemical reaction.
In Reaction A, a redox reaction oxidation-reduction occurred. Copper metal reacted with nitric acid to produce copper II nitrate. It also created nitrogen dioxide, and water which is decomposed from nitric acid. In reaction B, a double displacement reaction occurred for the reasons that when copper II nitrate reacts with sodium hydroxide, copper and sodium displace each other to create copper II hydroxide and sodium nitrate.
In Reaction C, a decomposition reaction proceeded for the reasons that when heat was added to copper II hydroxide, it decomposes to form two compounds, copper II oxide and water.Grenouille (11) Hard to see anything upsetting the top two choices. MISSILE LAUNCH and came on strong to win last start to break maiden at Bunbury when fresh and Patrick Carbery a bonus, in the mix. MORE BXAAR placed last start at Ascot and has two placings from three runs this prep, dangerous.
Duck Feet (4) 4. Brother's Keeper (12) 6. Prying Tom (11) 2. Rich Red (10) Stand-out between the top two picks. DUCK FEET last start winner at Ascot and could come on strong to threaten, among the main chances.
BROTHER'S KEEPER last start winner at Geraldton and has the speed to overcome drawing the widest barrier, among the chances.
PRYING TOM has the speed to overcome a very wide draw and two from three wins have been in the dry, don't dismiss. RICH RED unwanted by the market but right up there last start at Ascot when first up and generally strong second-up, place claims. Young Gina (15) 9. Rare Coin (1) 14. Remunerator (10) BLACKLINE first-up after 26 week spell and placed in both lead-up trials, perfectly placed. YOUNG GINA let-up and chased well to fall just short last start at Bunbury, each-way claims.
RARE COIN resumes from a 23 week spell and placed when trialling at Lark Hill, place only. The Gospel Sin (5) 5. Paris Texas (7) 4. Kimbo's Girl (8) 1. Majestic Man (1) Looks a toss up between the top two selections. THE GOSPEL SIN a winner at first outing this prep and rates highly with Shaun Mc Gruddy aboard, marginal top pick.
PARIS TEXAS back after 24 week break and placed in last trial at Lark Hill, should be thereabouts. KIMBO'S GIRL coming off a win at Bunbury when first up and should look to roll forward, in with a chance.
MAJESTIC MAN kept chasing and just missed last start at Ascot when first up, dangerous. A Good Plan (4) 2. It's Got It All (16) 16. Thunderplump (1) Solid pace expected in this one.
A GOOD PLAN has had a flying start to their career and likely to race on the speed, a winning chance. EASEWOLD first-up after 16 week break and won Belmont trial convincingly, place hope. IT'S GOT IT ALL led all the way to win at only start at Narrogin and has the speed to overcome a very wide draw, place best.
Private Hero (3) 2. Red Scarlet (5) 3. Royal Atom (4) 6. Mr Scary (6) PRIVATE HERO a winner at first outing this prep and Stephanie Lacy a bonus, the testing material. RED SCARLET finished strongly to end up midfield last start at Doomben and goes up in trip, for the exotics. ROYAL ATOM in strong form with two wins from eight attempts this campaign and returns to shorter trip, outside hope. MR SCARY has three placings from 11 runs this prep and drops in weight, for the wider exotics.
Wicked Express (3) 1.