Marissa

Newest questions and responses by Marissa
1. Calculus

Find a formula for a function of the form y=bxe−ax with local maximum at (0.5,0.3679). y=

2. Math

Start at 500,crate a pattern that subtracts 4 from each number.Stop when you have 5 numbers

3. Chemistry

Consider the reaction 2H2O(g) → 2H2(g) + O2(g) ΔH = +483.60 kJ/mol at a certain temperature. If the increase in volume is 42.7 L against an external pressure of 1.00 atm, calculate ΔU for this reaction. (The conversion factor is 1 L · atm = 101.3 J.)

4. Trigonometry

A scientist has 37 grams of a radioactive substance that decays exponentially. Assuming k=-0.3,how many grams of radioactive substance remain after 9 days.

5. History

The growing popularity of newspapers, magazines, and books in the United States during the 19th century contributed to which of these? The emergence of a uniquely American literary style The expansion of educational opportunities for women and minorities

6. math

The position of a bucket falling down a well can be represented by the function h(t)=-16t^{2} where t is time in seconds and h(t) is measured in feet. Based on this function, what is the velocity of the bucket after it has fallen for 4 seconds?

7. Chemistry

Write the symbol for the elements that fit the following descriptions 1. 10 electrons in each -3 ion 2. 18 electrons in each +2 ion 3. The alkaline earth metal in the third period

8. Calculus

A rectangular tank with a square​ base, an open​ top, and a volume of 4,000 ft cubed is to be constructed of sheet steel. Find the dimensions of the tank that has the minimum surface area. I'm not understanding how to get started and find the

9. Chemistry

How many moles of hydrogen from when 10 moles of methane react completely?

10. Chemistry

How many moles of water vapor react to yield 546.234 moles of hydrogen?

11. Chemistry

Write a conversion factor that could be used to convert between moles of methane and moles of hydrogen

12. Chemistry

What is the maximum mass of cobalt (II) phosphate that will precipitate from a solution prepared by adding an excess of K3PO4 solution to 100.0 mL of 5.0 M CoCI2? Sorry for all the confusion with different names we are working in a group and its easier to

13. Chemistry

When coal is burned, the sulfur it contains is converted into sulfur dioxide. This is SO2 is a serious pollutant, so it needs to be removed before it escapes from the stack of a coal fired plant. One way to remove the SO2 is to add limestone, which

14. Chemistry

A precipitation reaction takes place when a water solution of potassium phosphate, K3PO4, is added to a water solution of cobalt (II) chloride, CoCl2 Write a balanced equation for this reaction

15. Chemistry

Potassium permanganate, KMnO4, a common oxidizing agent, is made from various ores that contain manganese (IV) oxide, MnO2. The equation shows the net reaction for one process that forms potassium permanganate 2MnO2+2KOH+O2=2KMnO4+H2 Explain why the oxygen

16. Chemistry

Potassium permanganate, KMnO4, a common oxidizing agent, is made from various ores that contain manganese (IV) oxide, MnO2. The equation shows the net reaction for one process that forms potassium permanganate 2MnO2+2KOH+O2=2KMnO4+H2 What is the maximum

17. Home economics

List 10 careers in home economics

18. Chem

Which one of the compond are covalent HF RbF LiF NaF

19. english

Which type of faulty logic appears in this sentence? Dr. Bishop has never performed a surgery before, so he must not be equipped to be a good surgeon.

20. Chemistry

Calculate molarity of KNO3 solution if 69 g of salt are dissolved into 250 mL of solution

21. Science

A spring scaled is used to measure the weight of a object on the earth. The scale on the moon would read what?

22. Science

A spring scaled is used to measure the weight of a object on the earth. The scale on the moon would read what?

23. Science

A spring scaled is used to measure the weight of a object on the earth. The scale on the moon would read what?

24. calculus

what are the inflection points of 5x^2-45/x^2-25

25. Geometry

Given: BA is congruent to DC; BE is perpendicular to AC; DF is perpendicular to AC. Prove: BE is congruent to DF. The image is of rhombus ABCD. There is a segment connecting A and C with points E and F each about a third of the way into the segment.

26. Math

A recipe calls for 2/3 cups chocolate but I'm only making a fourth of the batch how much chocolate what I need

27. living skill

Calculating Voltage across a Resistor (Parallel Circuit and series circuit)

28. MATH

Use the following time value of money tables to answer the following questions. Assume that the annual rate of interest is 6% for each of the four following problems. i = 6% Time Periods (n) Future Value of 1 Present Value of 1 Future Value of an Annuity

29. math

find the percentile rank of 4.6 out of these numbers: 1.8, 2.5, 3.9, 4.6, 4.7, 4.8, 4.8, 4.9

30. physics

A man cleaning his apartment pushes a vacuum cleaner with a force of magnitude 55.8 N. The force makes an angle of 15.3 ◦ with the horizontal floor. The vacuum cleaner is pushed 3.55 m to the right along the floor. Calculate the work done by the 55.8 N

31. English

Would someone be willing to proof read my English essay? I proof read it but I don't know if I got all the mistakes.

32. Ap chem

How would the addition of hydrogen gas at constant temperature and volume effect rate=k[h2][I2]?

33. Chem

What is the order of rate = k[NO]2[Br2]. 2nd order?

34. Chem

Can someone help with this one? Half life of 55Cr is about 2 hours. A sample of the isotopes delivered from the reactor to lab requires 12 hours. What is the minimum amount of material that should be shipped to get 1.0 mg of 55Cr. I said 32mg but I got it

35. Chem

What would the unit be if you calculate the rate when A= 0.30 M and b= 0.30 M. I have the calculation done right and its 1.57 x 10 to the -3 but I don't know the unit

36. Chemistry

Does a k constant have a unit?

37. Chemistry

At 20 degrees celcius the vapor pressure of toluene is 22 mmhg and that of benzene is 75 mmhg. Assume an ideal solution, equimolar in benzene and toluene. At 20 degrees celcius what is the mole fraction of benzene in the vapor in equilibrium with this

38. Chemistry

24.0 mL of a 2.4 M silver nitrate is mixed with 32.0 mL of 2.0 M sodium. Calculate the mass of precipitae formed. Calculate the concentration of all ions remaining in solution after the precipitate forms. I don't know how to start this or where to go with

39. chemistry

16.5 mL of 2.5 M sodium sulfate is mixed with 35.5 mL of 4.5 M sodium nitrate. What is the concentration of all ions in the new solution?

40. Physics - Electric Field

Find the electric field at a point midway between 2 charges of +40.0e-9 C and +60.0E-9 C separated by a distance of 30.0 cm. My work: q1=40E-9 q2=60e-9

41. Math 222

I am having difficulties trying to do rational expressions. I have to use the words Domain, Excluded Value, Set, Factor, and Real Numbers to show how I got the answer. Can someone please help me solve this one? g^2-6g-55 ___________ g

42. Physics

A baseball player slides into third base with an initial speed of 3.8m/s. If the coefficient of kinetic friction between the player and the ground is 0.40, how far does the player slide before coming to rest?

43. chemistry

An equilibrium is dynamic. true or false

44. Mechanics, Rigid body

At t = 0 s a flywheel is rotating at 20 rpm. A motor gives it a constant acceleration of 1 rad/s^2 until it reaches 100 rpm. The motor is then disconnected. How many revolutions are completed at t = 21 s? What I've done so far is multiply my 20rpm and

45. physics

Two canoeists start paddling at the same time and head toward a small island in a lake. Canoeist 1 paddles with a speed of 1.40m/s at an angle of 45 degrees north of east. Canoeist 2 starts on the opposite shore of the lake, a distance of 1.5 km due east

46. geometry

One endpoint and the midpoint of a segment are given. Find the coordinates of the other endpoint. Show all your work. A. Endpoint: (-1,9) Midpoint: (-9,-10) Endpoint: _______ B. Endpoint: (9,-10) Midpoint: (4,8) Endpoint: ________

47. Math

What number is 1,000,000 greater than 337,676

48. History

What did the founding fathers of the United States create in order to ensure that one person did not ever have too much power in the government?

49. science

if you wanted to consult the geologic time scale for when the first vertebrates evolved, where would you look?

50. Accounting

During the week ended May 15, 2013, Scott Fairchild worked 40 hours. His regular hourly rate is \$31. Assume that his earnings are subject to social security tax at a rate of 6.20 percent and Medicare tax at a rate of 1.45 percent. He also has deductions of

51. Social Studies

What were the negative impact or effects of the Incas and Aztecs? Thank You

52. Social Studies

Has the effort of Westerners to aid the rest of the world done more good than harm? Its a opinon but i would like a answer please. Please make your answer at least 6 sentences. Thank you very much

53. ap biology

What barriers might hinder the acquisition of plasmids?

54. algebra

. Mrs. Crenshaw has confiscated 4 cell phones from 4 different students because they used them during class. To get the cell phones back, they have to answer the fol- lowing question: What is the probability that no student receives his or her own phone if

55. Statistics

I have 8 marbles: 3 blue, 1 green, 4v reds. What is the probability of selecting a blue marble twice with replacement and twice without replacement

56. algebra

There is an 18 inch sandwhich that Jenny cuts and gives half of the sandwhich to Demi and Joel gets 3/4 of what jenny has. Add all up to 18

57. Math

When Christy made tortillas for the first time, she used all the dough to make 10 tortillas. After making quesadillas, she decided that the tortillas were not large enough. The next time, using the same amount of dough, she made each tortilla the same

58. Physics

A man at point A directs his rowboat due north toward point B, straight across a river of width 100 m. The river current is due east. The man starts across, rowing steadily at 2.50 m/s and reaches the other side of the river at point C, 150 m downstream

60. English

How would you paraphrase this excerpt from "A Tale-Tell Heart" by Edgar Allen Poe; "I bade them search - search well. I led, at length, to his chamber. I showed them his treasures, secure, undisturbed"

61. Algebra

If f(x)=2x+1 and g(x)=3x-5, find f(g(2)).

62. math

A support wire runs from the top of a tower to the ground. If the tower is 1200 feet tall and the wire is attached to the ground 500 feet away from the tower, how long is the support wire?

63. Chemistry

Your space ship has docked at a space station above Mars. The temperature inside the space station is 24oC at a pressure of 745mmHg. A balloon with a volume of 425mL drifts into the airlock where the temperature is -95oC and the pressure is 0.115 atm. What

64. finance

company starting salary 75,000 retirement benefits 401k with annual contribution of 5% company will match 3% (for max contribution of 8% salary) avg 401k return within mutual fund options at 8% per year sign on bonus 0 annual bonus after 2 years of service

65. MATH

5000000 times x divied by y ?

66. MATH

what is : 4)x+y)-10

67. math

what is 71 times 45 equal

68. algebra

Find 2 consecutive integers, the smaller a perfect cube and larger a perfect square.

69. Calculus

I'm struggling some with the us of trigonomic properties. The problem is integral sin(2x)sec(x) dx and I don't understand how sin(2x)sec(x) simplifies into 2sin(x).

70. psychics

The lower frequency limit for human hearing is usually considered to be 20.0 Hz. (a) What is the speed of sound in m/s if the air temperature is 20.0ºC? (b) What is the corresponding wavelength for this frequency?

71. Physics

The lower frequency limit for human hearing is usually considered to be 20.0 Hz. (a) What is the speed of sound in m/s if the air temperature is 20.0ºC? (b) What is the corresponding wavelength for this frequency?

72. Guidance and discipline

At what age is it typical for a child to begin testing the word no

73. math

what number could represent the height of a bird 120 feet the surface of the ocean

74. math

it is claimed that the average age of employees in a large company is 50. a sample of 36 employees is taken and the average age was 49. the standard deviation of the population was 5. use a level of significance of 0.5. what do you think of the claim?

75. science

you need to prepare 30g of calcium cholride. you have 2m hydrochloric acid and a new container off pure calcium carbonate. Calculate the number of mole of calcium chloride that u need to prepare

76. math

jimmy is playing a dart game at an arcade. he can earn 2,3,or 6 points with each dart. she scored 24 points. how many ways could he score 24 points given that each dart thrown landed on the dart board?

77. math

Rohnda is in charge of buying food for the school picnic, she found that hot dogs are in packages of 24, buns in packages of 18, ketchup in boxes of 12, and mustard in boxes of 15. what is the least number of students that can be feed if each student

78. math

The greatest common factor of 2 numbers is 14, the least common multiple is 168. If the 2 numbers are not 14 and 168, what is the sum?

79. Math

i need an example problem using log10E=11.4+1.5m when E means radiated energy and m is means magnitude. the log has a base of 10 that's why the 10 is there. please help!!! Again, need an example problem relating it to earthquakes

80. Math

A bicycle trail is 7miles and 880 yards long.How many total yards is the bicycle trail

0.350L of 0.160 M NH3 is added 0.140 L of 0.100 M MgCl2 . How many grams of (NH4)2SO4 should be present to prevent precipitation of Mg(OH)2 (aq) ? The Ksp of Mg(OH)2 is 1.8 x 10–11.

82. physics

At the moment car A is starting from rest and accelerating at 5.0 m/s2, car B passes it moving at a constant speed of 45m/s. How long will it take car A to catch up with car B?

83. math

There are 5 yellow cards, 4 red cards, and 1 purple card. He draws a card at random, replaces it, and draws a second card. What is the probability that both cards will be red?

84. Health

Gonorrhea is spread through contact with the ________. A. Anus, !@#\$%^&, Mouth, Skin B. !@#\$%^&, Anus, Mouth, !@#\$%^& C. !@#\$%^&, Skin, !@#\$%^&, Anus D. Mouth, !@#\$%^&, !@#\$%^&, Fingers I think it's B?

85. p.e.

a scull is to rowing as a -------- is to yachting.

86. Calculus

Assuming that f and g are functions differentiable at a (though we do not know their formulas). Prove that f +g is differentiable at a using the definition of the derivative.

87. Physics

A dog running in the +y-direction at 6.0 hears its owner call from behind, and 2.7 later it's running at the same speed in the opposite direction. Calculate the dog's change in velocity. Calculate the average acceleration

88. Calculus

F(x)=|x-5| evaluate the following limits lim x->5- ( f(x)-f(5))/(x-5) lim x->5+ ( f(x)-f(5))/(x-5)

89. physics

A wire tooth brace used by orthodontists. The top-most tooth is protruding slightly, and the tension in the wire exerts two forces at 16 º angle on this tooth in order to bring it back into alignment. If the forces have the same magnitude of 19.5 N, what

90. physics

A 316-kg boat is sailing 12.0° north of east at a speed of 1.60 m/s. 39.0 s later, it is sailing 36.0° north of east at a speed of 4.00 m/s. During this time, three forces act on the boat: a 31.4-N force directed 12.0° north of east (due to an auxiliary

91. Physics

Two arrows are shot vertically upward. The second arrow is shot after the first one, but while the first is still on its way up. The initial speeds are such that both arrows reach their maximum heights at the same instant, although these heights are

92. Physics

A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 3.9 s later. If the speed of sound is 340 m/s, how high is the cliff? i know you use the equation y=(initial velocity)(time) + (1/2)(acceleration)(time^2) but I'm having

93. Science

What happens to approximately 60% of the energy released during the complete oxidation of glucose? A) It is used to synthesize more ATP. B) It is reused to supply the energy for anabolic reactions. C) It is stored in the body as fat. D) It is lost by the

94. science

In a micelle, why do you find the fatty acid chains of the of the phospholipid molecule are on the inside of the bilayer?

95. Calculus

How do you use imlicit differentiation to differentiate e^(xy)? I have the problem "use implicit differentiation to find dy/dx. e^(xy)+ x^2 - y^2 = 10. I've gotten to the point whereI have d/dx(e^(xy)) + 2x - 2ydy/dx = 0, but I can't go any further because

96. Calculus I

Find the derivative of y=ln((1+e^x)/(1-e^x)) I know that the derivative of y=ln(1+e^x) would be (e^x)/(1+e^x), but I'm not sure what to do with the 1-e^x on the bottom here. Can someone help please? Thanks!

97. Math

Delia works from 8:00 a.m. to 4:30 p.m. and has one hour each day for lunch. How much does she earn for a five-day workweek at \$4.80 per hour?

98. social studies

Were cassette tapes famous when they first came out?

99. biology

A dominant gene A produces wire-haired texture in dogs. Its recessive aamllele a produced smooth hair. Cross the heterozygous wire-haired dog with homozygous smooth-haired dog. List the genotype and phenotype ratios of all the possible offspring.