# joanna

Most popular questions and responses by joanna
1. ## General Chemistry

How many milliliters of 0.5M NaOH must be added to 200 mL of 0.1M NaH2PO4 to make a buffer solution with a pH of 6.9?

2. ## Chemistry

Estimate the value of the equilibrium constant at 500 K for each of the following reactions. 2H2S(g)⇌2H2(g)+S2(g) I have calculate my delta H which is 168.9 kj/mol but I don't know where to go from there

3. ## statistics

A bank loan officer rates applicates for credit. The rating are normally distributed with a mean of 200 and a standard deviation of 50. Find the P60, the score which separates the lower 60% from the top 40%. I get 212.7, using the normal distribution tool

4. ## MATH

In Mrs.Marshall'd classroom, 6/7 of the students play sports. Of the students who play sports, 4/5 also play as instrument. If there are 35 students in her class, how many play sports and an instrument?

5. ## math - gr 12

the social convenor has 12 volunteers to work at a school dance. Each dance requires 2 volunteers at the door, 4 volunteers on the floor, and 6 floaters. Joe and Jim have not volunteered before so the soicial convenor does not want to assign them to work

6. ## Univ Physics-resistance

A hollow cylindrical resistor with inner radius r1 and outer radius r2, and length l, is made of a material whose resistivity is rho. A.Find the resistance for current that flows radially outward. Divide the resistor into concentric cylindrical shells and

7. ## physics

A large grinding wheel in the shape of a solid cylinder of radius 0.330 m is free to rotate on a frictionless, vertical axle. A constant tangential force of 270 N applied to its edge causes the wheel to have an angular acceleration of 0.854 rad/s2. (a)

8. ## statistics

suppose that iq scores have a bell-shaped distribution with a mean of 97 and a standard deviation of 17. using the empirical rule, what percentage of iq scores are greater than 46? please do not round your answer.

9. ## Chemistry

In the reaction,C2H4(g) + 3O2(g) =2H2O(g) + 2CO2(g),what is the complete combustion of 12.5cm3 of ethene

10. ## Science

What happens when 1 Liter of Carbon Tetrachloride is poured into a container of Water?

11. ## physics

1. A closed magnetic circuit of cast steel contains a 6cm long path of cross sectional area 1cm square and a 2cm part of cross sectional area of 0.5cm square. A coil of 200 turns is wound around the 6cm length of the circuit and a current of 0.4ampere

12. ## Phys sci

Which one of the following frequency can set the string into resonant vibration? If a guitar string has a fundamental frequency of 500Hz a)250Hz b)750Hz c)1500Hz d)1750Hz

13. ## Maths,science

Choose the correct option and write 1) air,water, minerals, soil,are_ factors of an ecosystem ( physical, organic,inorganic)

14. ## physics

The large quadriceps muscle in the upper leg terminates at its lower end in a tendon attached to the upper end of the tibia (see figure (a)). The forces on the lower leg when the leg is extended are modeled as in figure (b), where vector T is the force of

15. ## Physics

A 6.5-kg bowling ball thrown with a speed of 5.4 m/!@#\$%^&s a stationary 1.75-kg pin. What is the velocity of each object? Assume that the coefficient of restitution is 0.75.

16. ## Chemistry

Compare and contrast the processes of nuclear fission and fusion, showing similarities and differences. Describe which, if any, of these processes is naturally occurring. If so, where?

17. ## Calculus

A rectangular plot of land is to be fenced in using two kinds of fencing. Two opposite sides will use heavy-duty fencing selling for \$3 dollars a foot, while the remaining two sides will use standard fencing selling for \$2 a foot. The fence is to cost

18. ## physics

A volume of gas v at temperature T1 and pressure P, is enclosed in a sphere. It is connected to another sphere of volume v/2 by tube and stopcock. This second sphere is initially evacuated and the stopcock is closed. If the stopcock is now opened and the

19. ## Math

A 17 foot pipe is cut into three sections. The longest section is 3 times as long as the shortest and the middle sized section is 2 feet longer than the shortest. Find the length of each section to the nearest foot

20. ## Math

assume that oil spilled from a ruptured tanker spreads in a circular pattern whose radius increases at a constant rate of 2 feet per second. how fast is the area of spill increasing when the radius of the spill is 60 feet? Note: you must state and use the

21. ## Chemistry

The rate constant for a certain reaction is = 4.30×10−3 s^-1. If the initial reactant concentration was 0.400 M , what will the concentration be after 19.0 minutes? Rate would be first order therefore I used. A=A initial*e^-kt I keep getting .0030 M but

22. ## chemistry

calculate the mass given element of each of the following compounds a) brimine in 50.0 potassium bromide, KBr b) Chromium in 1.00 kg sodium dichromate Na2Cr2O7

23. ## Statistics and Probability

A box contains 4 red and 5 blue marbles. Michele picks three marbles at random from this box. If Z is a random variable representing the # of blue marbles picked from the box, do the following. a. Express the probability mass function of Z in tabular form.

24. ## Calculus

an experimental farm has 3600 ft. of fencing to create a rectangular area that will be subdivided into 4 equal subregions, what is the largest total area that can be enclosed?

25. ## physics

Question Part Submissions Used A 11.5-kg cylinder rolls without slipping on a rough surface. At an instant when its center of gravity has a speed of 10.9 m/s, determine the following. (a) the translational kinetic energy of its center of gravity J (b) the

26. ## Precalculus

invests 7000 for 1 year part at 5% part at 11% and the remainder at 13% total amount of income from these investments was \$774. The amount of money invested at 13% was \$1200 more than the amounts invested at 5% and 11% combined find the amount invested at

27. ## physics

an ideal monatomic gas is allow to expand slowly until its pressure is reduced to exactly half its original value. By what factor those the volume changes if the pressure is (1)isothermal (2)adiabatic. Please is the answer suppose to be a calculation or an

28. ## MATH

Show three ways to estimate 3/5 ¡¿ 9 1/2. Identify each method you used.

29. ## accounting

. On June 1st, Green Pea, Inc. purchased \$1,200 worth of supplies on account. How does this transaction affect Green Pea's accounts? a. Increase supplies and accounts payable by \$1,200 b. Increase supplies and decrease cash by \$1,200 c. Increase supplies

30. ## physics

Use conservation of energy to determine the angular speed of the spool shown in the figure below after the 3.00 kg bucket has fallen 4.05 m, starting from rest. The light string attached to the bucket is wrapped around the spool and does not slip as it

31. ## Math

determine the value of k such that g(x)=3x+k intersects the quadratic function f(x)+2x^2-5x+3

32. ## math

I flip a fair coin seven times in a row. What is the probability that I get at most five heads?

33. ## Math

(i don't know if i posted but im just doing it again just in case) A 17 foot pipe is cut into three sections. The longest section is three times as long as the shortest and the middle sized section is two feet longer than the shortest. Find the length of

34. ## science

What is itvbarnoeso unscrambled ?

35. ## physics

A volume of gas v at temperature T1 and pressure P, is enclosed in a sphere. It is connected to another sphere of volume v/2 by tube and stopcock. This second sphere is initially evacuated and the stopcock is closed. If the stopcock is now opened and the

36. ## Math, Statistics

I know its 1 - P(5/128) but I don't think its correct?? I flip a fair coin seven times in a row. What is the probability that I get at most five heads?

37. ## math

I have a bag that contains 10 red marbles, 9 green marbles, and 6 blue marbles. I reach into it and take one marble at random. Keeping that marble, I reach into the bag again and take a second marble at random. a. What is the probability that the first

38. ## science

In Vista and Windows 7, which process allows you to display two documents side by side? A. Click the Windows button, choose Control Panel, and select the Tile Windows Vertically option. B. Right-click the mouse button in a blank area of the taskbar; in the

39. ## Physics

A simple pendulum has mass 1.14 kg and length 0.760 m. (a) What is the period of the pendulum near the surface of Earth? (b) If the same mass is attached to a spring, what spring constant would result in the period of motion found in part (a)?

40. ## math

Let A and B be events such that P(B)=0.28, P(B|A) =0.44 and P(A or B)=0.63, What is P(A)

41. ## chemistry

A sample of sulfer, mass 2.56 g is burned in excess oxygen inside a calorimeter of heat capacity 923JK and insulated by 815g of water. If the sole product of combustion is SO2, what is the expected increase in temperature? I don't need the answer, just the

42. ## chem

when 1.00g of sucrose C12H22O11 was combusted in a calorimeter to give CO1 and H20, the temperature rose from 25.00 to 27.32 C. The calorimeter itself had a heat capacity of 837JC and was submersed in 1500.0g of water. Find the heat of combustion of

43. ## Algebra 2

I need to know how to solve quadratic equations by factoring. Can you so a step by step explanation to this sample problem? 2 x -12x-28

44. ## chemistry

On a hot sunny day.... why is the chrome fender of a white convertable car with its top down cooler to touch, than its dark red plastic seats? Is it because the lighter the color is, the less heat is absorbed? why id an asphalt sidewalk warmer to touch on

45. ## science

In Vista and Windows 7, which process allows you to change the desktop background? A. Click the Start button, choose Control Panel, and select Display Properties. B. Right-click on the desktop; in the menu that appears, select Display Properties. C. Click

46. ## physics

A volume of gas v at temperature T1 and pressure P, is enclosed in a sphere. It is connected to another sphere of volume v/2 by tube and stopcock. This second sphere is initially evacuated and the stopcock is closed. If the stopcock is now opened and the

47. ## physics

vector A has a magnitude of 57 m and points in a direction 20 degrees below the positive x axis. vector B has magnitude of 70 m and points in a direction 57 degrees above the positive x axis. Find the magnitude of the vector D = A-B.

48. ## physics

A curve of radius 20 m is banked so that a 970 kg car traveling at 50 km/h can round it even if the road is so icy that the coeﬃcient of static friction is approximately zero. The acceleration of gravity is 9.81 m/s^2 Find the minimum speed at which a

49. ## physics

i need three different project topic in physics

50. ## physics

A volume of gas v at temperature T1 and pressure P, is enclosed in a sphere. It is connected to another sphere of volume v/2 by tube and stopcock. This second sphere is initially evacuated and the stopcock is closed. If the stopcock is now opened and the

51. ## physics

an ideal monatomic gas is allow to expand slowly until its pressure is reduce to exactly half its original volume. By what factor those the volume change if the process is (1)isothermal (2) adiabatic

52. ## FRENCH

COuld you please tell me if Ive translated these French words and phrases right? Est-ce qu(e) - Phrase introducing a question Ne Quitte pas - Wait a minute? Maintenant - Now Il y a des defiles et beaucoup de bals: -There are some parades and many dances Ce

53. ## Physics

The mass of the Moon is 7.35 x 10^22 kg. At some point between Earth and the Moon, the force of Earth's gravitational attraction on an object is cancelled by the Moon's force of gravitational attraction. If the distance between Earth and the Moon (centre

54. ## English

I trying to find out what life was like in England in 1564 on rich and poor people, what jobs, kind of places they lived, social life, how much money to live, what food and drink they had. I have been unable to find a website that gives me this

55. ## MATH

I don't get it. At all. HELP!! ¤Ð-¤Ð 😭 Jenna lives 4 3/10 miles from school. She estimates that she travels 4¡¿2¡¿5, or 40 miles each week. Is her estimate an overestimateor an underestimate? EXPLAIN!!!!

56. ## probabilities

A bag contains 3 green balls. 2 red balls and a white ball. A boy randomly draws balls from the bag one at a time (with replacement) until a red ball appears. Find the probability that he will make at least 3 draws.

57. ## physics

i need three project topics in physics. Help please

58. ## physics

an ideal monatomic gas is allow to expand slowly until its presssure is reduced to exactly half its original value. By what factor does the volume change if the pressure is (1) isothermal (2) adiabatic

59. ## Pre-algebra

Kiron invests \$22,700 at 14% interest. About how much interest will he earn in 6 months? a.\$19,068 b.\$3,178 c.\$1,589 d.\$530

60. ## calculus

f(x)=x8+7x2+613(x−1)2(x+6)6

61. ## Calculus

The value of y changes by 3 units when x changes by 0.1 unit. About how fast is y changing?

62. ## Organic Chemistry

What are proper techniques to induce crystallization from a saturated solution? (Select all correct answers.) Allowing the solution to cool down. Scratching the outside of the container with a glass rod. Seeding the solution. Adding a solvent that lowers

63. ## Physics

Consider the electric field created by a very long charged line of negative linear charge density -2.50 nC/m. A small positive point charge of 7 mC moves from a distance of 9 cm to a distance of 17 cm. How much work is done by the electric field?

64. ## social studies

why would a store owner spend so much money on decoating their store?

65. ## college english

Please Help Me Revise My Essay: An unknown author once said, “A good teacher is like a candle - it consumes itself to light the way for others.” Of all the teachers I have had throughout my educational history there is only one that stands out the

I need to write an essay on something I have accomplished using 5 adjectives and 2 inference words. What are some examples of inference words?

67. ## data management (gr.12)

ana finds 11 shirts in his size at a clearence sale. How many different purchases could ana make? the answer is 2047, any idea how to answer this? thanks!!

68. ## world histoy

why did the United States declare war on Germany?

69. ## physics

A student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of 16.0 m/s. The cliff is h = 25.0 m above a flat horizontal beach, as shown in the figure below. How long after being released does the stone strike the

70. ## physics

A ball is thrown directly downward with an initial speed of 8.95 m/s, from a height of 29.0 m. After what time interval does it strike the ground?

71. ## Pre Calc

Find cos 2A if tan A = 5/12 and

72. ## Math

Tony is making half-pound bags of trail mix for a camping trip with his scout troop. He has 101 /2 pounds of peanuts and 91 /2 pounds of raisins. How many bags of trail mix can he make in all?

73. ## ethics

What are some ethical issues that a warden faces with the correctional officers and inmates

74. ## medical records

how important is having the ability to read medical charts and reports? Why can abbreviations in charts be a cause of concern? How would you ensure that your staff and other health care professionals are proficient in medical abbreviations and terminology?

75. ## computer packages

describe the following in not less than five sentence with examples. (1) rational database (2) schema

76. ## algebra

how do you Write a point-slope equation for the line with the given slope that contains the given point. with m=-3;(-2,-5)

77. ## Alegaba 2

Two sides of a triangles are equal in length. the length of the third side is three meters less than the sum of the lengths of the other two sides. What is the length of the longest side of the trangle if its perimeter is 29 meter?

78. ## algbra

Explain how to find the sum positive eight plus negative ten using game chips, then give the answer.

79. ## health projects

i need ideas how to make a reproductive system of the female? i don't have no clue how to make it

If I just have a picture of la sala and it's neat and tidy and has a television in it, which would be the correct response? 1.Mi familia acaba de limpiar la sala. 2.Mi familia mira la television. 3.Mi familia necesita limpiar la sala. 4.Mi familia limpia

81. ## math helpy

Evaluate: 16^-3/4

82. ## Economics

The Andrews Corporation produced satellite dishes, was purchased by another compay, which was a cable company: The Total Cost function for the New Company is: TC = 1,000 + 16Q – 16Q2, where the demand curve for Satellite Dishes is PS = 400 – QS and

83. ## social studies

what is the difference between vertical and horizontal integration?

what is the probability of not throwing 7 or doubles for 6 consecutives throws with a pair of dice? help please?!?!!

85. ## history

Why was the Civilian Conservation Corps so effective in bringing work and opportunities to Americans during the Great Depression? Use examples to support your answer.

86. ## chemistry

Moles chemistry? Calculate the mass of solute required to prepare ib the solution 200cm^3 of solution containig 0.50 mol dm ^-3 cl-iond prepared by dissolving cacl2.6h2o in water.

87. ## chemistry

Find the number of moles in 12×10^24 CO2 molecules 1mole is equal to 6.0×10 ^23 ? 12x10^24 Then division of them but the answrr did not match the answer of the book

88. ## crime control model

•How do advocates of the crime control model view plea-bargaining?

89. ## juvenile deliquency

What is a sub-cultural issue that is most proematic in causing juvenile delinquency

90. ## criminal justice

To some, the victim's rights movement is more an exercise in symbolic politics than a substantive program. As a result, some critics argue that many of these programs are really more interested in severe punishment of the defendant than in helping victims

91. ## criminal justice

how each player in the criminal justice system impacts the decision-making process.

92. ## math

Consider the line 9x - 7y =4 What is the slope of a line parallel to this line? What is the slope of a line perpendicular to this line?

93. ## Chemistry lab reports online?

Are there any websites with other students' lab reports with calculations online? I do not want to copy and am completely against plagiarism. I just want to look at others' examples to help in giving me ideas on how to write my own and make sure I have

94. ## law

Why did Congress repeal the mandatory federal sentences for drug offenses in 1970?

95. ## math

the challenge involves in dealing with the owner is to use a 20 meter fencing material to build a pig pen so that the owner will not be buying any additional materials considering also that one side of the pen is the outside wall of his garage? what is the

96. ## english literature

How does The Misfit embody both verses of Matthew 12:35? "A good man from the goodness of his good heart brings forth good things; an evil man from the evilness of his evil heart brings forth evil deeds."

97. ## statistics

1. 35% of North Americans do not think that college education is a contributory factor to economic success. A random sample of seven North Americans is selected

98. ## science

Which Windows feature allows you to personalize your computer system? A. My Pictures C. Default Programs B. Control Panel D. Computer

99. ## science

In Vista and Windows 7, which process allows you to change the desktop background?