Posted by Ana on Saturday, May 3, 2014 at 11:23am. A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº

8,031 questions
1. Chemistry - Science (Dr. Bob222)

Posted by Ana on Saturday, May 3, 2014 at 11:23am. A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº = -0.76 V Cu2+ + 2 e- → Cu(s) Eº = 0.34 V

asked by Ana on May 5, 2014
2. Chem AP help!

A zinc-copper battery is constructed as follows at 25°C: Zn | Zn2+(0.15 M) || Cu2+(1.70 M) | Cu The mass of each electrode is 150. g. The cell potential when the cell is first attached is 1.13V How long can this battery deliver a current of 5.00 A before

asked by Daya on March 12, 2012
3. Chemistry Equation(again!)

Posted by chrissy on Saturday, January 6, 2007 at 1:23pm. In a lab expirement you add copper(II)nitrate to pure zinc. Write a balanced equation for this expirement and predict if a reaction will occur. For Further Reading Chemistry Equation - DrBob222,

asked by chrissy-needs Chem help ASAP on January 6, 2007
4. Chemistry

A zinc-copper battery is constructed as follows. Zn | Zn2+ (0.70 M) || Cu2+ (2.30 M) | Cu The mass of each electrode is 200. g. (a) Calculate the cell potential when this battery is first connected. 1 V (b) Calculate the cell potential after 10.0 A of

asked by Amy on March 29, 2009
5. Chemistry

A zinc-copper battery is constructed as follows at 25°C. Zn|Zn^2+ (0.15 M)||Cu2+(3.00 M)|Cu The mass of each electrode is 200. g. a) Calculate the cell potential when this battery is first connected. - i got this to be 1.14V b.) Calculate the cell

asked by Pamela on April 28, 2011

A zinc-copper battery is constructed as follows at 25°C. Zn|Zn^2+ (0.15 M)||Cu2+(3.00 M)|Cu The mass of each electrode is 200. g. a) Calculate the cell potential when this battery is first connected. - i got this to be 1.14V b.) Calculate the cell

asked by Mandy on April 28, 2011

A zinc-copper battery is constructed as follows at 25 degree C: Zn | Zn2+(0.15 M) || Cu2+(1.70 M) | Cu The mass of each electrode is 250. g. I found the cell potential to be 1.13V and the cell potential after 5.00 A of current has flowed for 8.00 h is

asked by Puja on March 10, 2012
8. college chemistry

A zinc-copper battery is constructed as follows: Zn | Zn+2(0.10 M) || Cu+2 (2.50 M)| Cu The mass of each electrode is 200.0 g. Each half cell contains 1.00 liter of solution. a) Calculate the cell potential when this battery is first connected. b)

asked by Stephanie on April 28, 2010
9. chem

Copper sulfate is a blue solid that is used as an algicide. Solutions of copper sulfate that come in contact with zinc metal such as the surface of galvanized (zinc-plated) steel- undergo the following reaction that forms copper metal on the zinc surface:

asked by Anonymous on October 5, 2009
10. Chem Equation

In a lab expirement you add copper(II)nitrate to pure zinc. Write a balanced equation for this expirement and predict if a reaction will occur. Zinc is more active than copper, so zinc will donate electrons to the copper ions, precipating it as copper.

asked by alisha on January 4, 2007
11. chemistry

pure zinc metal into a solution of copper(II) sulfate, the zinc will slowly dissolve to produce zinc sulfate solution, and the copper(II) ion of the copper(II) sulfate will be converted to metallic copper. Write the unbalanced equation for this process.

asked by astoeck on October 2, 2010
12. (19) Chemistry - Science (Dr. Bob222)

Use the following information to answer this question: Cu+(aq) + e- → Cu(s) E° = 0.521V Cu2+ (aq) + e- → Cu+ (aq) E° = 0.153 V. Given these half cell reactions, an aqueous solution of Cu+ ion in the absence of O2(g) : A. will be thermodynamically

asked by Ana on May 8, 2014
13. chemistry - Science

A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº = -0.76 V Cu2+ + 2 e- → Cu(s) Eº = 0.34 V The mass of each electrode is 200 g. Each half-cell

asked by Ana on May 3, 2014
14. chemistry - Science

A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº = -0.76 V Cu2+ + 2 e- → Cu(s) Eº = 0.34 V The mass of each electrode is 200 g. Each half-cell

asked by Ana on May 3, 2014
15. algebra II

I need help solving these types of problems here is one one of them. Can somone show me how to solve them.thanks Production Requirements An electronics company produces transistors, resistors, and computer chips. Each transistor requires 3 units of copper,

asked by jas on June 8, 2007
16. math

A 200g alloy is made of copper and zinc. the number of copper atoms is 3 times that of zinc, a)calculate the number of copper and zinc atoms. b)calculate the weight of copper and zinc in the alloy. so for a) can i assume that the mol ratio is cu:zn = 3:1?

asked by nelson on April 28, 2017
17. chemistry

Is this balanced properly 2H2O2----> 2H2O +O2 Thank you for the reactions of zinc and acetic acid. REAL QUESTION, if I was to rub all the copper off of a new penny down to the zinc, what would be the appearance of the zinc if I left it in vinegar (acetic

asked by lulu on November 13, 2016
18. CHEMISTRY

brass is a subtitutional alloy consisting of a solution of copper and zinc. a particulae sample of red brass consisting of 80% copper and 20% zinc by mass has a density of 8750kg/m^3. a. what is the molality of zinc in the solid solution and B. what is the

asked by lulu78 on October 14, 2010

I am given a question where I have to state which combination of electrodes will result in the greatest voltage and which will result in the lowest voltage. The metals given are Zinc, Copper, Silver and Hydrogen I calculated the Ecell for each combination

asked by Sara on May 15, 2015
20. Physics

Mixing copper and zinc atoms produces the alloy brass. What would be produced with the fusion of copper and zinc nuclei?

asked by Rob on April 25, 2008
21. Science

Which way do electrons flow when a copper strip is placed in a Zn2+ solution: from the copper to zinc ions or from the zinc ions to the copper?

asked by Nancy on March 11, 2008
22. RE: Physics

If an incline has a difference in height from one end to the other of 17.8 cm and has a length along the incline of 1.19 m, what is the angle that the incline makes with the horizontal reference surface? Physics - Damon, Saturday, February 15, 2014 at

asked by Christina on February 15, 2014
23. Math

An alloy contains zinc and copper in the ratio 7:9. Find the weight of copper if it has 31:5 kg of zinc

asked by Aishu on April 1, 2017
24. general chemistry

I need the oxidation half reactions, reduction half reactions, and net ionic equations for the following reactions: 1)magnesium +0.1M zinc sulfate 2)copper+0.1M zinc sulfate 3)zinc+0.1M copper(II)sulfate 4)zinc+3M HCl 5)copper+3M HCl 6)0.1M potassium

asked by masooma on November 13, 2010
25. math

A statue is made of a mixture of copper and zinc in a ratio of 11:4 (copper to zinc). If the weight of the statue is 3165 pounds, what is the weight of the copper?

asked by Megan on January 29, 2012
26. algebra 2

Posted by hellogoodbie on Saturday, January 16, 2010 at 3:24pm. Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm. How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x

asked by hellogoodbie on January 16, 2010
27. Algebra

One alloy of brass is 70% copper and 30% zinc. Another alloy of brass is 40% copper and 60% zinc. How many grams of each of these alloys need to be melted and combined to obtain 300 grams of a brass alloy that is 60% copper and 40% zinc

asked by Jonn on October 22, 2016
28. chemestry please check my anwers.

1.How do acid-base reactions differ from oxidation-reduction (or "redox") reactions? Answer Acid-base reactions involve an exchange of protons whereas redox reactions involve an exchange of electrons.

asked by asap on April 3, 2013
29. Chemistry

I don't know how to get the mole ratios of the following: Copper to Chloride Zinc to Chloride Zinc to Copper There are the moles I have of each; Copper 4.25*10^-3 mol Zinc 3.67*10^-3 mol Chloride 2.27*10^-2 mol

asked by Jake on March 2, 2011
30. Science

1.0 g of copper was heated in a crucible, while stirring, and .2g of unreacted copper was recovered usoing hydrochloric acid as a solvent, how much copper would precipitate when zinc is later added to the copper oxide/acid solution?

asked by R Johnson on March 13, 2013
31. Chemistry

In electrochemistry, why is my experimental voltage value of my cell lower than the standard electrode potential? I used zinc and copper as the electrodes and connected zinc sulphate and copper(II) sulphate using a salt bridge. I got 0.85V instead of

asked by Siobhan on June 22, 2007
32. chemistry

Before 1982 the US Mint cast penny coins from a copper and zinc mixture. If a 1980 penny weighs 3.051g and contains 0.153g zinc, what is the percent of copper in the coins?

asked by Twynna on January 26, 2011
33. chemistry

Before 1982 the US Mint cast penny coins from a copper and zinc mixture. If a 1980 penny weighs 3.051g and contains 0.153g zinc, what is the percent of copper in the coins?

asked by Twynna on January 26, 2011
34. Chemistry

Given the density of copper 8.96g/mL, zinc 7.14g/mL, and brass 8.36g/mL. What is the fraction of copper and zinc in brass (expressed as %)? Please show me step by step how to calculate this. Thank you.

asked by Anonymous on September 19, 2012
35. Science

What type of reaction each one is, synthesis , decomposition , single displacement or double displacement? a. zinc + copper (II) sulphate >>>> copper (II) + zinc sulphate b. MG+ HCL >> H2 + MgCl2

asked by hi on October 20, 2018
36. Chemistry

If a copper sample containing some zinc impurity is to be purified by electrolysis, the anode and the cathode must be which of the following? a. anode: pure copper cathode: pure zinc b. anode: pure zinc cathode: pure copper c. anode: pure copper cathode:

asked by John on April 14, 2008
37. ALgebra

Brass is an alloy formed from copper and zinc in the ratio 3:2, based on weight. If 120g of copper is needed for a certain piece of brass, how much zinc will be needed?

asked by BLANK on January 9, 2016
38. Chemistry Equation

In a lab expirement you add copper(II)nitrate to pure zinc. Write a balanced equation for this expirement and predict if a reaction will occur. I THINK Bob Pursley answered this question a day or so ago. Zinc is higher in the activity series than copper;

asked by chrissy on January 6, 2007
39. Chemistry

A battery is constructed based on the oxidation of magnesium and the reduction of Cu^2+. The initial concentrations of Mg^2+ and Cu^2+ are 1.2*10^-4M and 1.5M, respectively, in 1.0-L half-cells. The initial voltage of the battery is 2.83V with the standard

asked by Emma on May 2, 2010
40. Science

My physical science class is doing an experiment on the mass of pennies. I hypothesized that newer pennies would have less mass because cheaper materials are being used. I found that before 1982, pennies were made from 95% copper/5% zinc, and after 1982

asked by Beth on September 8, 2007
41. College Chemistry 104

Students are attempting to construct a battery in the laboratory that will light up a light bulb. Compare the following lists prepared by students and determine which student will not be able to successfully build a "battery" that will light up the bulb.

asked by Claire on May 10, 2013
42. Honors Chemistry

We did the gold penny lab, where we bathed a copper penny in a hot zinc-NaOH mixture to turn it a silver color, then we heated that in a flame to turn it a gold color. There are two questions that go with this lab that I don't understand, however: 4. Did

asked by Emily on October 7, 2009
43. Chemistry

Zinc, copper, lead, and mercury ions are toxic to Atlantic salmon at concentrations of 6.42 × 10–2 mM, 7.16 × 10–3 mM, 0.965 mM, and 5.00 × 10–2 mM, respectively. What are the corresponding concentrations in milligrams per liter? Concentration of

asked by Mae on September 28, 2017
44. chemistry

A 0.8552g sample of copper alloy is treated with 8 molar nitric acid and filtered and the precipitate is ignited giving a residue of 0.0632g of SnO2. The zinc is determined in one half of the filterate by precipitating it as ZnNH4PO4 and then igniting with

asked by william on September 15, 2017
45. chemistry

Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 . A fitting composed of common brass has a total volume of 114.5 .How many atoms of copper does the fitting contain?

asked by lisa on September 10, 2010
46. chemistry

write out the reaction, predicting products where applicable. Zinc metal is added to a solution of copper(II) sulfate. Copper metal is produced and zinc sulfate is left in solution.

asked by amber on December 10, 2007
47. Physical Science

Which part of an electric circuit resists the flow of charge when it changes electrical energy into other forms of energy? A. battery B. copper wires C. switch D. light bulb i've posted this before but it's getting buried. i don't think its A or B.

asked by bubbie on March 26, 2013
48. Chemistry

The standard electrode potentials for zn/zn and cu/cu are -0.76v and 0.34v respectively at 298k.calculate the free energy change when a zinc rod is dip into a zinc tetraoxosulphate(vi) solution and a copper rod is dip into a copper(ii)tetraoxosulphate(vi)

asked by Precious on November 7, 2018
49. Algebra

Bronze is an alloy that is made of zinc, tin, and copper in a specified proportion. Suppose an order is placed for 1000 pounds of bronze. The amount of tin in this order of bronze is two times the amount of zinc, and the amount of copper is 10 pounds more

asked by Trish on February 17, 2016
50. Math

There are two alloys consisting of zinc, copper and tin. The first alloy contains 25% zinc and the second alloy contains 50% copper. The percentage of tin in the first alloy is twice that in the second alloy. 200 kg of the first alloy and 300 kg of the

asked by Tamasa on June 19, 2016
51. Chemistry

Zinc has three major and two minor isotopes. For this problem, assume that the only isotopes of zinc are the major ones, zinc-64, zinc-66, and zinc-68. The atomic mass of zinc-64 is 63.9291 Da, that of zinc-66 is 65.9260 Da, and that of zinc-68 is 67.9248

asked by Jess on May 3, 2013
52. Englaish

Posted by rfvv on Sunday, June 29, 2014 at 4:13pm. People use pockets when they eat Brussels waffles. ---------- Is this sentence grammatical? Is the use of 'pockets' here grammatical? English - Writeacher, Saturday, June 28, 2014 at 10:38am Do you mean

asked by rfvv on June 29, 2014
53. Physics

1)An alloy of copper zinc has a mass of 4.9kg.when suspended in water.0.98kg of water was displaced by it.calculate the mass of zinc in the alloy if 2.5 and 19.6 are the specific gravity of the zinc and copper respectively 2) A steel ball of diameter

asked by Skyboy on December 18, 2015
54. Chemistry - Science (Dr. Bob222)

Liquid chloroform (CHCl3) is placed in a closed container and allowed to equilibrate with chloroform vapor. With the temperature held constant, additional chloroform is introduced into the system, and the vapor-liquid equilibrium is reestablished.

asked by Ana on May 10, 2014
55. Physics

Suppose you make an electromagnet with a copper wire and a battery by putting the two ends of the wire on the two ends of the battery. If you switch the side of the battery, are you changing the magnetic poles of the wire?

asked by Anonymous on April 9, 2014
56. Science

Suppose you make an electromagnet with a copper wire and a battery by putting the two ends of the wire on the two ends of the battery. If you switch the side of the battery, are you changing the magnetic poles of the wire?

asked by Anonymous on April 9, 2014
57. Maths

1^2014 + 2^2014 + 3^2014 + 4^2014 + 5^2014 divided by 5, remains ______

asked by maths on November 13, 2016
58. Multiple Choice

Physics 2. Which of the following is equivalent to one ampere? (Points : 1) 10 s/10 C 10 C/10 m 1.5 C/1.5 s 15 C/10 s Question 3.3. A stream of moving charges results in a current of 5.6 A. How long does 116 C of charge take to flow past a fixed point?

asked by Steven on May 8, 2014
59. Chemistry

the current U.S. penny is only 2.5% copper the remaining portion is zinc. Given the density of copper as 8.94 g/cm and the density of zinc is 6.57 g/cm, calculate the density of a penny.

asked by Devante on September 11, 2014
60. Chrmistry

What is the percentage recovery if 0.98g of copper is left when reacting 0.5g of copper sulphate with excess zinc?

asked by Erron on April 8, 2017
61. chemistry

calculate the mass in grammes of copper that will be deposited by dissolving 6.5g of zinc in copper tetraoxosulphate(vi) solution

asked by jer on November 8, 2015
62. chemistry

calculate the mass in grams of copper that will be deposited by dissolving 6.5g of zinc in copper tetraoxosulphate(vi)solution

asked by kabiru ali on November 4, 2015
63. Chemistry

Before 1982 U.S pennies were made of solid copper. As the price of copper rose,the U.S mint switched to a composition that is 97.5% zinc and 2.5% copper. A penny minted after 1982 is 19 mm in diameter and 1.6 mm thick. What is the volume of a penny in mL?

asked by Boriqualissa on October 15, 2007
64. Physics

Calculate the amount of copper deposited in a zinc/Copper electrode of electrolytic cell when 2.5A of electric current is passed in 10 minutes?

65. physics

Posted by michelle quendarsv on Saturday, November 20, 2010 at 5:26pm. Posted by michelle quendarsv on Saturday, November 20, 2010 at 3:55pm. if it takes 726 watts of power to move a mass 36 meters in 14 seeconds, what is the mass? i really need like, step

asked by michelle quendarsv on November 20, 2010
66. science

Posted by Josh on Saturday, March 17, 2007 at 10:58pm. How many grams of hydrochloric acid are required to react completely with 4.30g of zinc? How many molecules of gas will be produced? For Further Reading science - DrBob222, Saturday, March 17, 2007 at

asked by Josh on March 18, 2007
67. Math

An alloy is made up of 25% copper, 30% iron an rest being zinc. Find the mass of zinc in 720 gm of the alloy

asked by Tanya on December 3, 2016
68. Maths

The ratio of zinc and copper in an alloy is7:9 if the weight of the copper in the alloy is 11.7 kg , find weight of the zinc in the alloy

asked by Eklavya joshi on February 25, 2017
69. Chemistry

For a voltaic cell that's made with zinc and copper {reaction equation: Zn(s) + Cu2+(aq) ---> Cu(s) + Zn2+(aq)}, if the concentration of zinc nitrate increases, would the cell voltage decrease, or would it increase? Thanks!

asked by Rainbow on April 7, 2014
70. algebra 2

Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm. How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and compute f(-2) algebra 2 - hellogoodbie,

asked by hellogoodbie on January 16, 2010
71. maths

An alloy is made by using copper and zinc in the ratio of 17:3 how much zinc is used to make 4kg of the alloy?

asked by Anonymous on November 9, 2010
72. Science? (for dddd47906)

If you follow the directions on the Post a New Question form (did you read them?), you'll have better luck getting a good response. http://www.jiskha.com/post_form.cgi Posted by dddd47906 on Monday, May 12, 2014 at 12:17pm. Just wondering for my report,

asked by Writeacher on May 12, 2014
73. Physics

When a battery is not used in a circuit, a voltmeter measure 1.492V across the terminals of the battery. When a 2.50Ω light bulb is connected to the battery, the potential difference across the terminal of the battery is 1.453V. Calculate the internal

asked by exo-L on December 13, 2018
74. Chemistry

A strip of zinc metal was placed in a beaker that contained 120mL of a solution of copper(2) nitrate, Cu(NO3)2(aq). The mass of the copper produced was 0.813g. Find the initial concentration of the solution of copper(2)nitrate. Can u help me out with

asked by Kristien on March 5, 2013
75. English

Posted by rfvv on Thursday, April 24, 2014 at 7:41am. the Great Fire of London by Janet Hardy Gould ---------------------------- Is this book a novel? English - Writeacher, Thursday, April 24, 2014 at 7:53am I've never read it, but if it's a novel that's

asked by rfvv on May 12, 2015
76. Chemistry

The standard electrode potential for Zn/Zn2+ and cu/cu2+ are -0.96volts and +0.3volts respectively at 293k.(a) calculate the free energy change when a zinc rod dips into 1M of zinc tetraoxosulphate(vi) solution and a copper rod dips into a 1M of copper

asked by Queeneth on May 25, 2017
77. math

The ratio of zinc and copper in an alloy is seven ratio nine if weight of copper in the alloy is eleven point kg then find the weight of zinc in the alloy

asked by nisha on January 2, 2013
78. Delete

Is it possible to have this question removed? Thanks so much! :) Subject: Pre-Calc Date: Saturday October 4, 2014 Time: 10:27am

asked by Tori on October 5, 2014
79. science

when a zinc is placed in a copper(ii)nitrate solution,the strip becomes coated with copper.write down the oxidation half reaction for the reaction that takes place.

asked by BONNY on August 25, 2012
80. Random Question

Posted by Alex on Saturday, June 4, 2011 at 12:55pm. Based on readings from the first 20 chapters of "Invisible Man", what does the narrator mean when he refers to himself as "invisible"? Is it because of all the situations he been in and no one really

asked by Alex on June 4, 2011
81. math

The ratio of zinc and copper in an alloy is 7:9. if the weight of copper in the alloy is 11.7 kg, find the weight of zinc in alloy?

asked by swagnik on February 23, 2012
82. Math

A metal alloy consists of copper, zinc and tin in the ratio of Unexpected text node: ’a’. The alloy is found to have 20 g of zinc. a) What is the weight of the metal alloy? b) calculate the weight of the other two components. Not sure how I am supposed

asked by Anonymous on October 5, 2018
83. Chemistry 219

An amount of 1.250g of an alloy (90% Ag, 10% Cu) was treated with HNO3 and H2SO4 to form Ag2SO4 and CuSO4. The solution was then treated with Cu wire to precipitate silver. The resulting solution was treated with excess zinc to precipitate copper. (show

asked by Anonymous on February 8, 2011
84. physics

A 8 V flashlight battery has an internal resistance of 1.7 Ω when new, and 8 Ω when old. Imagine this is a resistor in series with the battery mounted INSIDE the battery itself, which describes the chemical degradation of the battery with age. Calculate

asked by Naina on July 19, 2011
85. Chemistry

I am having a lot of trouble understanding acid-base reactions. I was able to struggle through most of the homework, but I'm not usre about these questions. 1) Can an acidic solution be made less acidic by adding an acidic solution? 2) Pennies manufactured

asked by Mary on December 4, 2009
86. chemistry

Procedure: 1. Place the zinc nitrate solution into a beaker and connect the zinc electrode so that it is partially submerged in the solution. 2. Place copper (II) nitrate solution into the porous cup and connect a copper electrode so that it is partially

asked by Sarah on April 15, 2008
87. chemistry

Procedure: Place the zinc nitrate solution into a beaker and connect the zinc electrode so that it is partially submerged in the solution. Place copper (II) nitrate solution into the porous cup and connect a copper electrode so that it is partially

asked by Sarah on April 15, 2008
88. Chemistry

The equation is: CuSO4(s) + Zn(s) -> Cu(s) + ZnSO4(aq) 3.22 g of powdered zinc is added to 200ml of 0.5M copper sulfate solution. What mass of copper is deposited? Hi guys. I am confused about the stoichmetry question. Q: The equation is: CuSO4(s) + Zn(s)

asked by G on October 10, 2015
89. College Chemistry

Zinc, copper, lead, and mercury ions are toxic to Atlantic salmon at concentrations of 6.42 times 10 to the -2 mM, 7.16 times 10 to the -3 mM, 0.965 mM, and 5.00 times 10 to the -2 mM, respectively. What are the corresponding concentration is milligrams

asked by Bekah on October 2, 2011
90. Chem

Zinc, copper, lead, and mercury ions are toxic to Atlantic salmon at concentrations of 6.42 times 10 to the -2 mM, 7.16 times 10 to the -3 mM, 0.965 mM, and 5.00 times 10 to the -2 mM, respectively. What are the corresponding concentration is milligrams

asked by HELP on October 1, 2012
91. science

'Copper' pennies actually contain very little copper. If a penny contains 91.768 % of its total volume zinc and 8.232 % of its total volume copper, what is its density? (d of Cu = 8.95 g/cm3; d of Zn = 7.14 g/cm3.)

asked by Arthur on August 18, 2009
92. Algebra

This question never got answered and I would appreciate it if someone could take a look at it. Simplify 12(6^/(5^-4^) + 7 My thoughts 12(36/(5^-4^) + 7 12(36/9) + 7 12 (4) + 7 12 * 11 132 Algebra - Steve, Saturday, August 23, 2014 at 11:49pm Your notation

asked by Faye on August 24, 2014
93. SCIENCE

what are the benefits of copper to the industry, economy, and society? what are all the organisms that are affected by copper? what is meant by the term Bioaccumulation? Include the names of any organisms that are affected and how they are affected by

asked by LOUIS on February 27, 2013

I am given a question where I have to state which combination of electrodes will result in the greatest voltage and which will result in the lowest voltage. The metals given are Zinc, Copper, Silver and Hydrogen I think that silver and copper would give

asked by Sara on May 12, 2015
95. English

Posted by rfvv on Friday, August 29, 2014 at 11:25pm. At the End of a letter or mail, people use the expression as follows, what is the meaning 'Best' here? What else can we use between friends? ... ... ... Best, Sam English - Writeacher, Friday, August

asked by rfvv on September 1, 2014
96. ALGEBRA

I know the answers, but am having trouble writing the equation. Their ages are 17 and 8.5, and 14.5 Can I get help with the equaiton? The sum of the ages of Sonia, Collin, and Ana is 40. Sonia is twice as old as Ana. Ana is 6 years younger than Collin. How

asked by BELLA on November 22, 2009
97. science

Based on the reactivity series, decide whether the following reaction will occur. If you think there will be no reaction, write down why you think this. If you think a reaction will happen, write down why you think it will happen, and the word equation to

asked by ishaan on June 27, 2011
98. arithmetic

Ana sees a computer that costs \$1600. The store manager says next week will be on sale \$350 less. What percent will Ana save

asked by Anonymous on April 2, 2014
99. Spanish for John

SINGLE OBJECT PRONOUNS = UN COMPLEMENTO SIMPLE DIRECT-OBJECT PRONOUNS: Ana no me visita. = Ann does not visit me. Ana no te visita. = Ann does not visit you (fam.) Ana no le visita = Ann does not visit him, you (ONLY IN SPAIN), otherwise: Ana no lo visita.

asked by SraJMcGin on May 10, 2008
100. English

Posted by rfvv on Saturday, April 9, 2016 at 3:37am. 1. Try to do this at least 5 to 10 times. 2. Try to do this at least from 5 to 10 times. (Doe s#1 mean #2? Can we use 'from' before 5?) •English - Writeacher, Saturday, April 9, 2016 at 8:38am The two

asked by rfvv on April 11, 2016