1) An old wooden tool is found to contain only 11.9 percent of 14C that a sample of fresh wood would. How many years old is the tool? 2) A specimen taken from the wrappings of a mummy contains 7.02 g of carbon and has an activity of 1.34 Bq. How old is the

2. Physics

An apartment has a living room whose dimensions are 2.5 m 4.8 m 5.9 m. Assume that the air in the room is composed of 79% nitrogen (N2) and 21% oxygen (O2). At a temperature of 27°C and a pressure of 1.01 105 Pa, what is the mass (in grams) of the air? g

3. chemistry

Chromium metal can be plated onto an object from an acidic solution of dichromate ions. What average current is required to plate 17.8 g of chromium metal in a time of 2.20 h?

4. chemistry

1)Ethanol is made by the fermentation of sugar. (a)Suggest a temperature for carrying out the fermentation and explain your answer. -40°C(ish), ??to do with enzymes; they can't or don't work as well in other temps./controls the speed of fermentation

5. Geometry

Find the area of a regular pentagon with radius 3cm. Round to the nearest tenth. No picture is given, but I believe a circle can surround the figure. I'm not really sure how to find the area of the figure when the side length isn't given. Can you guys help

6. Chemistry

1)Ethanol is made by the fermentation of sugar. (a)Suggest a temperature for carrying out the fermentation and explain your answer. -40°C(ish), ??to do with enzymes; they can't or don't work as well in other temps./controls the speed of fermentation

7. physics

A crane in a marble quarry is mounted on the rock walls of the quarry and is supporting a 2900kg slab of marble as shown in the figure. The center of mass of the 750kg boom is located one-third of the way from the pivot end of its 15-m length, as shown.

8. Chem

Specify the number of unpaired electrons for each of the species shown below. CuCl2- (linear) Ni(NH36) 2+ NiCl4 2- (tetrahedral) CoF6 3- (weak field) Co(en)3 3+ (strong field) (en = "ethylene diamine") Would it be: 1 2 2 3 3 ??

9. Physics

The artificial sweetener NutraSweet is a chemical called aspartame (C14H18N2O5). (a) What is its molecular mass (in atomic mass units)? u (b) What is the mass (in kg) of an aspartame molecule? kg I know I have to get the totally mass of the aspartame, but

10. Mechanical engineering

A bullet of mass 50 grams is fired horizontally into a wooden block of mass 0.2kg. The wodden block is suspended from the ceiling by a long string as shown in the diagram. After impact the bullet is embedded in the block and bullet and the block swing

11. Algebra II

1) Find the exact value of cos 105 degrees by using a half-angle formula. 2)Find the solution of sin 2theta = cos theta if 0 degrees

12. physics repost

1. A stone is dropped from rest into a well. The sound of the splash is heard exactly 1.50 s later. Find the depth of the well if the air temperature is 10.0°C. 2. Calculate the sound level in decibels of a sound wave that has an intensity of 2.25 µW/m2

13. Algebra II

Find the exact value of cos 375 degrees. Answer: (sqrt6 + sqrt2)/4 Is this correct?

14. Physics

Three moles of a monatomic ideal gas expand adiabatically, and its temperature decreases from 430 to 160 K. (a) What is the work done by (or done to) the gas? Include the algebraic sign. J (b) What is the change in the internal energy of the gas? Include

15. chemistry

During the electrolysis of molten aluminum chloride in an electrolytic cell, 5.40 g of aluminum is produced at the cathode. Predict the mass of chlorine produced at the anode.

16. chemistry

A weak base with a concentration of 1.3 mol/L has a percent ionization of 0.72%. What is the Kb of this weak base?

17. chemistry

If the concentration of Pb2+ is found to be 2.3 x 10-9 mol/L in a saturated solution of Pb3(PO4)2, what is the Ksp of Pb3(PO4)2 ? This is my work thus far it is as far as I could get: Ksp = [Pb2+] [Pb3(PO4)2] = [2.3 x 10-9 mol/L][Pb3(PO4)2]

18. Algebra II

Find the exact value of sin(theta/2) if cos theta = 2/3 and 270 degrees

19. History

what aspect of the compromise of 1850 was the most contentious ?

20. chemistry

If the concentration of Pb2+ is found to be 2.3 x 10-9 mol/L in a saturated solution of Pb3(PO4)2, what is the Ksp of Pb3(PO4)2 ?

21. Algebra II

Find cos theta if sin theta = 3/5 and 90 degrees

22. chemistry

Find the temperature at which the reaction below is spontaneous given this data: Hf^o of NH3(g) = - 46 kJ/mol, S^o of NH3(g) = 192.5 J/mol·K, S^o of N2(g) = 191.5 J/mol·K, S^o of H2(g) = 130.6 J/mol·K. N2(g) + 3H2(g) 2NH3(g)

23. Physics

The artificial sweetener NutraSweet is a chemical called aspartame (C14H18N2O5). (a) What is its molecular mass (in atomic mass units)? u (b) What is the mass (in kg) of an aspartame molecule? kg

24. Chem

Which group shows the correct order of first ionization energy? Ca > Na > K Al > Si > P K > Ca > Ge Na > P > Cl Cs < Rb < Na I know the closer the element is to the right side of the table, group 8, the higher the ionization level, and the lower the group,

25. chemistry

What mass of Ag2CO3 would be found in 1.4 L of a saturated solution if the Ksp of Ag2CO3 is 8.2 x 10-12?

26. Physics

The temperature of a monatomic ideal gas remains constant during a process in which 4500 J of heat flows out of the gas. How much work (including the proper + or - sign) is done on the gas? J

27. chemistry

24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5.

28. Chem

Which of the following coordination compounds will most likely form a precipitate when treated with an aqueous solution of silver(I) nitrate? [Cr(NH3)3Cl3] [Cr(NH3)6]Cl3 [Cr(NH3)Cl]SO4 Na3[Cr(CN)6] Na3[CrCl6]

29. U.S. HISTORY

What new tactic of the war was introduced by Sherman's " march to the sea " ?

30. Chem

What is the sum of geometric and optical isomers that the complex ion Co(en)2Cl2+ exhibits? How do I begin to figure this out?

31. chemistry

24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5.

32. chemistry

24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5.

33. Algebra II

Which of the following expressions are not equal to 1? A) sin^2 theta + cot^2 theta sin^2 theta B) (sin^2 theta/1-cos theta)-cos theta C) sec^2 theta + tan^2 theta D) cot^2 theta sin^2 theta/cos^2theta Answer: D

34. Chemistry

Calculate the equilibrium concentration of all ionic aqueous species in a solution containing 1.30 M HCl and 4.0 M C6H5OH (phenol, Ka=1.6 x 10^-10). What is the pH of the solution?

35. physics repost

Calculate the sound level in decibels of a sound wave that has an intensity of 2.25 µW/m2. F

36. Physics

A runner weighs 560 N (about 130 lb), and 74% of this weight is water. (a) How many moles of water are in the runner's body? moles (b) How many water molecules (H2O) are there? molecules

37. chemistry

24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 x 10-5.

38. Chem

If the molar mass of monatomic deuterium (D) is 2.0141 g, then what is the density of diatomic deuterium (D2) gas at 25.0°C and 1.00 atm? I know the equation for density is: d=m/v What equation(s) do I need to use to solve this?

39. chemistry

What is the percent ionization of a 1.38 mol/L weak acid if its Ka = 2.7 x 10^-6? Thanks again!

40. Chem

Which of the following elements can form chemical compounds. CHECK ALL THAT APPLY. Xe Rn Kr Ne H He Is this a trick question...can't all of them form chemical compounds?

41. Algebra II

Verify that (sec theta/sin theta)(cot theta/csc theta) = csc theta is an identity. Thanks

42. chemistry

Calculate the value of the equilibrium constant (Kc) for the reaction shown, if SbCl5 was found to be 5.57% decomposed at 521K when its initial concentration was 7.60M. SbCl5 SbCl3 + Cl2

43. chemistry

A cell, transferred 0.146 mol of electrons with a constant current of 1.24 A. How long, in hours, did this take?

44. Language art

I'm in 5th grade. No idea about music. My teacher asked me to write papers about music, 10-15 songs, that have interesting and good vocabulary lyrics. Help please

45. U.S. HISTORY

what was the result of the jackson's indian removal act ?

46. English Grammar

Do you have a book? Have you a book? Have you got a book? I don't have a pen. I have not a pen. I haven't got a pen. ------------------------ Are they all grammatical?

47. chemistry

Find the temperature at which the reaction below is spontaneous given this data: Hfo of NH3(g) = - 46 kJ/mol, So of NH3(g) = 192.5 J/mol·K, So of N2(g) = 191.5 J/mol·K, So of H2(g) = 130.6 J/mol·K. N2(g) + 3H2(g) ßà 2NH3(g)

48. History

Hi, my history task for this weekend is to write an essay on this topic: "Women in World War II: An important step in the women's lieration or another opportunity for exploition" -Could you give me any insight,tips,information or starters to make this

49. Algebra II

An insect population P in a certain area fluctuates with the seasons. It is estimated that P= 17,000 + 4500sin (pi)(t)/52, where t is given in weeks. Determine the number of weeks it would take for the population to initially reach 20,000. How do I solve

50. Chem

When 0.500 g of copper(II) sulfate pentahydrate is heated at a temperature of 300°C for twenty minutes it loses some water of hydration. If the resulting sample weights 0.427 g then what is the formula of the resulting compound? What equation(s) can I use

51. Chem

Why are complex ions of Zn+2 colorless?

52. Chemistry

A tank contains 0.450 kg of oxygen(O2) compressed into a volume of 2.32 L. Estimate the gas pressure (in atm) inside the tank at 5 degrees celsius. Do I convert 0.450 kg from grams to moles, and if I do, do I use the molar mass of oxygen?

53. Chem

How many liters of hydrogen gas are needed to generate 90.0g of water 25C and 1atm pressure? What are the conversions I need?

54. Calculus

Will someone send me the ti 83 steps for: determine the graph of the equation: 9x^2+25y^2+z^2=225 if one is available.

55. Chem

How many liters of hydrogen gas are neede to generate 90.0g of water of 25.0°C and 1 atm pressure? What is the equation I can use to figure this?

56. French

Good Afternoon, Could you please see if i have translated this english to french correctly? Most squirrels are active during the day, beginning at dawn, often resting midday, and active again until dusk. Squirrels are most active during the fall,

57. Physics 12

I've been doing alot of extra questions for physics lately, and these four are still giving me trouble. Please help me out and help me solve them, including Free Body Diagrams if possible. 1. If a curve with a radius of 60m is properly banked for a car

58. Physics

A runner weighs 560 N (about 130 lb), and 74% of this weight is water. (a) How many moles of water are in the runner's body? moles (b) How many water molecules (H2O) are there? molecules I dont' unstand what to do here. I know have to fine mole per h2o

Please check this question for me thanks What method of sterilization uses the same agents as are used to disinfect instruments ? A dry heat B gas C chemical D surgial asepisis I pick C

60. phyiscs repost 2

Calculate the sound level in decibels of a sound wave that has an intensity of 2.25 µW/m2 For this question don't I use B=log10(I/IO) So it would be B=log10(2.25/1.0e-12) right?

61. Calculus

Show that the rectangle with the largest area that is inscribed within a circle of radius r is a square. Find the dimensions and the area of the inscribed square. My respect goes to those who know how to tackle this one.

62. Algebra II

State the phase shift of y=cos(theta-[pi/3]). Then graph the function. I know that you cannot graph on this site but how do I solve for the phase shift and to graph the phase shift, would I first have to graph the current equation? Thanks.

63. Algebra II

Find the exact value of: cos315 degrees. Is the answer sqrt of 2/2? Thanks

64. Algebra II

Find sec theta if tan theta =1/4 and 180 degrees

65. Math

Un=0.5*1.2^n Sketch this for n= (0,1,2,3,4,5) How do you sketch this?

66. history

i am not quite clear why the No child left behind act has been called unconstitutional. Many articles that I've read say that it is because it requires states to pay to go forth with the program. It violates the spending clause but can anyone explain

67. trig

y = sin(-3x + 3) Amplitude = Period = Two x- intercepts = y - intercept = Domain = Range = Shift along x = Shift along y = Kind of reflection =

68. Algebra II

1)Find the exact value of sin 165 degrees. Answer: (sqrt6 + sqrt2)/4 2) Simplify: (4m/5n^2)- (n/2m) Answer: (8m^2-5n^3)/10n^2m Thanks

69. Biology

I'm doing a report on the red panda, and I have to explain why the organism is classified in that group. The red panda's species is fulgens, but I'm not sure how to explain why its species is fulgens. Also, are there any other organisms in the Genus

70. trig

y = cos(4x/3 minus 1) amplitude? Period? Two x - intercepts? y-intercept? Domain? Range? Shift along x? Shift along y? Kind of reflection?

71. trig

I am doing a similar assignment as Anaa please help! y = 3cos(x-1) Amplitude: Period: Two x - intercepts: y-intercept: Domain: Range: Shift along x: Shift along y: Kind of reflection Thank you so much!

72. Physics

An engine has an efficiency of 59% and produces 5300 J of work. Determine each of the following. (a) the input heat J (b) the rejected heat J

73. Chem

Which of the following elements has the largest known oxidation number (in magnitude)? Pt Au Os Fe Ru

74. SCI

I need help finding info. on the following I am searching online snd not having a lot of luck on what i need. including speaker notes, that explains: • What carbohydrates are, the difference between simple and complex carbohydrates, how sugars are broken

75. English Lit

If you're familiar with James Baldwin please help me. I need to identify his writing style. So far I got something in between stream of consciousness and lots of poetic devices but I think I need something more concrete than that. HELP?

76. us history

What gropu was largely responsible for funding the builing of the railroad system in the U.S.?

77. History

What country did cuba win its independence from at the start of the 20th century ?

78. PHYSICS

how could an element emit alpha and beta particles and result in the same element?

79. anatomy

what's the area behind your knees called

80. English

Who is to blame for the death of Romeo and juliet? My clues i think are, Friar, Nurse, Fate, Parents, mercuito, tybalt,prince and their haste. i need some help understanding why

81. Algebra II

Find the exact solution(s) of the system: (x^2/4)-y^2=1 and x=y^2+1 Answer:(4,sqrt3),(4,-sqrt3) 2)Write an equation for an ellipse if the endpoints of the major axis are at (-8,1) and (8,1) and the endpoints of the minor axis are at (0,-1) and (0,3).

82. physical

what is body composition measured by using calipers?

83. microeconomics

the monopolist and the perfect competitor differ in that?

84. U.S. HISTORY

what philosophy blames the poor for their economic situation?

85. history

which group did the virginia plan favor ?

86. French

Good Afternoon, Could you please see if i have translated this english to french correctly? Most squirrels are active during the day, beginning at dawn, often resting midday, and active again until dusk. Squirrels are most active during the fall,

87. Math

4)Un=0.5*1.2^n Sketch this for n= (0,1,2,3,4,5) How do you sketch this?

88. U.S. HISTORY

whyat area in North America was point of contention between FRANCE / ENGLAND?

89. Physical science

What is the distance from one wave to the next?

90. History

why was the south in favor of the mexican american war ?

91. Health/ Basic Clinical Procedures

please check my answer thanks An objective sign is one that A can be observed by another person B precedes a disease C is felt by the patient and can not be obsserved by another person D causes the pt the most trouble I picked A

92. math

lim x-> -infinity 1/(sqaure root of 4/x^2 plus one) i don't understan why the answer is 1.

93. Social Studies

What was the name of the fake government of france and who led it? Thanks so much. ^-^

94. Math

1)AP has U6=12.5 and U19=32 a+5d=12.5 (&) a+18d=32 (2) (2)-(1), d=1.5 therefore, a=5 (a)What is the nth term?Tn=5+(n-1)1.5 (b)What is the sum of 4 terms between U10 and U13 inclusive? 2)Un=1/2^n-3 (a)What is the nature of this sequence? (b)Calculate the

95. marketing

what is the decision facing Virgin Galactic

96. Algebra II

solve the equation e^2 ln x - ln (x+2) = 8/3

97. history

what event(s) helped lead the USA to the joining World War two ?

98. Health/ Basic Clinical Procedures

please check my answer thank you True or Faise I said True Cilia prevent the entrance of pathogens into the body by providing an acidic envioroment