# Kristin

Popular questions and responses by Kristin
1. ## Chemistry

write the balanced equation for the ionization of the weak base pyridine, C5H5N, in water

2. ## calculus

The function f is continuous on the closed interval [0,6] and has values that are given in the table below. x |0|2|4|6 f(x)|4|K|8|12 The trapezoidal approximation for(the integral): 6 S f(x) dx 1 found with 3 subintervals of equal length is 52. What is the

3. ## Math

The top of a tree makes angles s and t with Points K and L on the ground, respectively, such that the angles are complementary. Point K is x meters and Point L is y meters from the base of the tree. A)In terms of x and y, find the height of the tree.

4. ## Math word problem

Patsy has cheerleading practice on every fourth school day. She wants to be in the school play, but they have practice on every sixth school day. If both started on September 5th, what would be the first date that she has to choose between cheerleading and

5. ## Help me solve??

XYZ has vertices X(5,6), Y(9,12), and Z(12,8). it is translated right 8 units and up 3 units. What are the coordinates of X', Y', and Z' ?

6. ## Math help!

Jack has the following scores on exams in his math class. 81, 87, 93, 89, 61, 81 If he wants to make his performance sound as good as possible, which measure should he use—the mean, the median, or the mode of his exam grades when he talks about how he is

7. ## Physics

A coiled Hookean spring is stretched 10 cm when a 1.5kg mass is hung from it. Suppose a 4 kg mass hangs from the spring and is set into vibration with an amplitude of 12 cm. A. Find the force constant of the spring. B. Find the Maximum restoring force

8. ## Chemistry

The ethylammonium ion, CH3CH2NH3+, has a pKa of 10.81. It reacts with water to form ethylamine, CH3CH2NH2 and H3O+. Which of the following statements is true at pH 7? A.) ethylamine predominates B.) ethylammonium ion predominates C.) the pH is higher than

9. ## Chemistry

What symbol is used to show the standard reduction potential of an oxidation reaction in a half cell? The sub means what follows is a subscript So the 0 is a superscript and the sub is its subscript E^0 sub cell*** E^0 sub red E^0 sub oxid All of the above

10. ## Survey Math help

A movie complex has eight different movie theaters. The manager of the complex wants to conduct a survey to determine which snacks to add to the menu. Which represents the best sample the manager could use for the survey? Would I do specific ages the first

11. ## Analytical Chemistry

A 10.0 mL sample of whiskey was diluted to 500.0 mL. A 4.00 mL aliquot of the diluted sample was removed and the ethanol, C2H5OH, was distilled into 50.00 mL of 0.02150 M K2Cr2O7 and oxidized to acetic acid. The excess Cr2O72– was then back titrated with

12. ## calculus

Meg's pension plan is an annuity with a guaranteed return of 4% per year (compounded quarterly). She would like to retire with a pension of \$20,000 per quarter for 10 years. If she works 30 years before retiring, how much money must she and her employer

13. ## math

five students make the following guesses on the number of jelly beans in a jar: 72, 78, 68, 60 and 84. the guesses were off by 14, 2, 4, 6 and 10 (not in order). how many jelly beans are in the jar?

14. ## Chemistry

The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta

15. ## Chemistry

I'm trying to find the solubility of Ca(OH)2 in .0125 mol/L aqueous NaOH. Here is my data: Vol of solution used per titration: 20mL Conc of HCl: .1201 mol/L Average Titre: 4.71 I need to calculte: 1. the TOTAL [OH-] in the saturated solution of Ca(OH)2 in

16. ## PHYSICS

Two 75 kg hockey players skating at 5.50 m per s collide and stick together. if the angle between their initial directions was 120 degress, what is their velocity after the collision?

17. ## math

In a lottery game, a player picks 9 numbers from 1 to 43. How many different choices does the player have if order doesn't matter?

18. ## Chemistry

What is the standard cell potential of a cell made of theoretical metals Ms/Ma^+2 and Mb/Mb^+2 if the reduction potentials are -0.19V and -0.85 V, respectively? +0.66V -0.66V +1.04 V*** -1.04V

19. ## physic

A 0.20 kg ice cube at 0.0° C has sufficient heat added to it to cause total melting, and the resulting water is heated to70deg.Cel. > How much heat is added? (For water Lf=334kj/kg > andLv=2257kj/kg >

20. ## Math

max has a box of 200 colored blocks. the box has an equal number of green and blue blocks and equal number of red and yellow blocks. if max arranged all of the green blocks in stacks of 12 and all of the blue blocks in stacks of 7, how many red blocks are

21. ## Chemistry

If solution A had a pH of 8, and solution B had 1,000 times this hydrogen ion concentration what would be the pH of solution B, and would solution B be acidic or basic?

22. ## Chemistry

What mass of copper(II) nitrate would be produced from the complete reaction of 65.3 g of copper, according to the chemical reaction shown below? Cu + 2 AgNO3 ----> Cu(NO3)2 + 2 Ag Use the masses to two decimal places using the periodic chart in the front

23. ## Physics

A 3.30-kN piano is lifted by three workers at a constant speed to an apartment 28.8 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 197 W of power, and the pulley system is 75.0% efficient (so

24. ## Calculus

A fragment of bone is discovered to contain 20% of the usual carbon-14 concentration. Estimate the age of the bone to the nearest hundred years, given that Carbon-1 is radioactive with half-life of 5730 years and the rate of decay is given by the following

25. ## Physics

If a projectile is launched from Earth with a speed equal to the escape speed, how high above the Earth's surface is it when its speed is three-fifths the escape speed? I keep getting the answer 2.56x10^6 m after solving it a few different ways. Help would

26. ## what??

im not trying to fool anything this is not a name change.MS.SUE Im not trying to be disrecptful since you do help a lot of kids but I also have talking to a lot of kids to and they say that sometimes your very rude and mean....im just trying the help the

27. ## calculus

compute the average velocity of a stone over time intervals 1, 1.01 1, 1.001 1, 1.0001 and .99,1 .999,1 .9999,1. use this to estimate instantaneous velocity at t=1 All i can figure out the formula should be s(t1)-s(t0) over t1-t0 how does that give you a

28. ## trig

find the coordinates of the terminal point on the unit circle determined by t=9pt/7 to two decimal places

29. ## West and Worlds since 1500

Which of the following are ways that intellectual, political, social, and religious developments of the seventeenth century were related, especially in regard to the dynamics of the Scientific Revolution? Check all that apply. The English Revolution

30. ## math

I just saw this guy post this here and I think he needs help??? A recipe calls for 4 pounds of fruit.you have 60 ounces of fruit. A.do you have as much fruit as you need? B.if not,how much more do you need?

31. ## math

An urn holds 13 identical balls except that 2 are white, 4 are black, and 7 are red. An experiment consists of selecting two balls in succession without replacement and observing the color of each of the balls. How many outcomes are in the sample space for

32. ## literature

What are the parts of speech to each word in this sentence: I like the movie Clueless its based on Jane Austens novel Emma.

33. ## AP US Government

Where in the Constitution are judicial nominations described? What language is used to describe the roll of the Senate in Supreme Court nominations? Where in the constitution is the Electoral College described (Hint: two places) Since this is not my area

34. ## Chemistry

The solubility of compounds containing the carboxylic acid group can be increased by reaction with a) sulfuric acid b) nitric acid c) sodium hydroxide d) water e) benzoic acid Would it be sodium hydroxide since it is a base?

35. ## physics

A tennis ball is dropped from the top of a building. It falls for 2.5 seconds before it hits the ground. (a) What velocity is the tennis ball traveling right before it hits the ground? (b) How high is the building?

36. ## statistics

The average temperature in households is 67.6 degrees F. The standard deviation is 4.2 degrees F. A random sample of 51 households is to be selected What is the probability that the average of this sample will be within 1.4 STANDARD ERRORS of the

37. ## Chemistry

Four sets of conjugate acid/base pairs and Ka of the acid are given. Which pair would be the best to form a buffer at pH = 9.2? You can use the Henderson-Hasselbalch equation to answer this question. HCNO/CNO- 3.5 x 10-4 HC2O4-/C2O4- 5.1 x 10-5 H2CO3/HCO3-

38. ## Chem

Caculate the volume of CO2 gas given off at 756 mm Hg and 23C when 150 kg of limestone(CaCO3) is heated until it decomposes according to the following reaction:CaCO3(s)=CaO(s)+CO2(g)

39. ## 3rd math

Bethany has 40 apples. Write a subtraction story about the apples that would require regrouping. Then write the answer in a complete sentence.

40. ## math

An urn holds 13 identical balls except that 2 are white, 4 are black, and 7 are red. An experiment consists of selecting two balls in succession without replacement and observing the color of each of the balls.

41. ## Physics

You attach one end of a spring with a force constant k = 893 N/m to a wall and the other end to a mass m = 2.02 kg and set the mass-spring system into oscillation on a horizontal frictionless surface as shown in the figure. To put the system into

42. ## math

please explain how to get the answer to this question. five students make the following guesses on the number of jelly beans in a jar: 72, 78, 68, 60 and 84. the guesses were off by 14, 2, 4, 6 and 10 (not in order). how many jelly beans are in the jar?

43. ## Math

If you put me into 7 equal groups with 3 in each group and 5 are left over, what number am I?

44. ## Physics

A driver in a car traveling at a speed of 56.0 mi/h sees a deer 116 m away on the road. Calculate the minimum constant acceleration that is necessary for the car to stop without hitting the deer (assuming that the deer does not move in the meantime).

45. ## AP Chemistry

This is part of a marathon problem, we have to identify the five compunds of H, N, and O described below. For each compound, I have to write a Lewis structure that is consistent with the information given. a.) All the compunds are electrolytes, although

suppose you have 2 cars, and the larger one is twice as massive as the smaller one. If you and a friend push on them so that their accelerations are equal, how must the forces applied to the cars compare? a. the force on the larger car is equal to that on

47. ## chemistry

When 0.100 mol of carbon is burned in a close vessel with 8.00g of oxygen, how many grams of carbon dioxide can form?

48. ## physics

a rocket blasts off and moves up with an acceleration of 12 m/s2 until it reaches 30 m then the engine shuts down and the rocket continues in free fall. What is the max hieght of the rocket and what is the total duration of the rockets flight?

49. ## Chemistry

The Ka for the reaction of acetic acid and water is 1.8 x 10-5. Which of the following statements is true at pH 7? A.) there is much more acetic acid than acetate ion B.) there is more acetate ion than acetic acid C.) the concentration of acetate ion is

50. ## Physics

The focal length of the objective of a telescope is 0.2 m and the eyepiece has a focal length of 1.6 m. What is the length of the telescope? A. 1.8 m B. 1.4 m C. 1.6 m D. .90 m E. 8.0 m

51. ## Economics

2. If a firm increases all of its inputs by 60 percent and its output increases by 90 percent, then you know that: A) it is encountering diseconomies of scale. B) it is encountering economies of scale. C) it is encountering constant returns to scale. D)

52. ## physics

If an arrow is fired at 200km/h horizontally, about how long will it take to strike a target 30 meters away?

53. ## Physics

The position vector r of a particle moving in an xy plane is given by [r = (6t^3-3t)i + (4-1t^4)j] with r in meters and t in seconds. What is the angle between the positive direction of the x axis and a line tangent to the particle's path at t = 3 s? Give

54. ## Math

To subtract 91 from 99, do you need to regroup? Explain

55. ## Chemistry

How many moles of chlorine are there in 16.0 mL of 0.450 M CaCl2? 0.0072 mol 0.0144 mol 0.0216 mol 0.0375 mol none of the above I had chose 0.0072 and had submitted it in my assignment, but it had said it was wrong. I chose 0.0072 because I did this

Find a rule that gives the third number from the first two numbers. Fill in the blanks.....10, 4, 5, ? 15, 7,7, ? 19,9,?

57. ## Physics

A rocket with a mass M moves along an x axis at the constant speed vi=40 m/s. A small explosion separates the rocket into a rear section (of mass m1) and a front section; both sections move along the x axis. The relative speed between the rear and front

58. ## Grammar

What is the direct object, indirect object, predicate nomnitive or predicate adjective in the following 2 senteces? 1.It is a book about his experiences near Walden Pond in Massachussetts. 2. The book is full of inspiring quotations about his search for

59. ## Physics

Suppose you have a stack of 9 identical oak planks, each of which have a mass of 8.0 kg. You are required to pull the seventh plank from the stack (counting from the top). If the coefficient of friction between oak and oak is 0.6, how hard do you have to

60. ## physics

A 0.205 kg bird flying along at 7.8 m/s sees a 0.029 kg insect heading straight toward it with a speed of 15 m/s (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch. What is the bird's speed

61. ## Chemistry

Anhydrous aluminum oxide can be reduced to aluminum according to thisa chemical equation: 2 Al2O3 (s) ---> 4 Al (l) + 3 O2 (g) Calculate the mass of aluminum oxide reacted if 82 g of Al was produced and the percent yield was found to be 89.3%

62. ## Chem 100

at 1 atm how much energy is required to heat 67 grams of H2O(s) at -22 degrees C to H2O(g) at 159 degrees C

63. ## Chemistry

What is the pH of a solution which has hydroxide concentration, [OH-], equal to 7.6 x 10-4 M? 0.88 3.12 10.9 13.1 none of the above I had chose 3.12 for this one and this one was also wrong. I did this because I did the equation -log(7.6*10^-4) and got

64. ## science

Which of the following is true about an object that floats in water? (1 point) The object is less dense than frozen water. The mass of the object is less than that of water. The density of the object is less than that of water. The volume of the water is

65. ## algebra

Suppose D=(w+2)(w-3)(w+6).For what three values of w will D have a value of 0?

66. ## Chemistry

I don't understand how you know what state designation things are in a chemical equation. For example this is given: 2 (NH4)3PO4 (__) + 3 Ba(NO3)2 ---> Ba3(PO4)2 (__) + 6 NH4NO3 (__) How do you just know what to put for their state or phase designation?

67. ## Schindler's List Essay

Directions: We recently watched the movie "Schindler's List," and now we have to write an essay. So I chose to write it based on this question: What are the three most important reasons for Schindler's success in saving 1,100 people? This assignment is

68. ## math

find the missing length of the right triangle one side is 20 and th other side is 48?? help

69. ## chem

The total pressure in a flask containing air and ethanol at 257C is 878 mm Hg. The pressure of the air in the flask at 257C is 762 mm Hg. If the flask is immersed in a water bath at 300C, the total pressure is 980 mm Hg. The vapor pressure of ethanol at

70. ## Physics

What is the difference in volume (due only to pressure changes, not temperature or other factors) between 1000 kg of water at the surface (assume 4 degrees C) of the ocean and the same mass at the deepest known depth, 8.00 km? (Mariand Trench; assume also

71. ## Chemistry

To charge a lead storage battery you must apply a direct current to it. hold a magnet close to it. force alternating current through it.*** increase the pressure on it.

72. ## Geometery help"Steve"

The point Q(x,y) is reflected in the origin. Use arrow notation to describe the original point and its reflection. I chose this: (x,y) to (x,y) Am I right?

73. ## chemistry

a. How many atoms of hydrogen are in 25.0 g of ammonia (NH3)? Use the format 6.02E+23 for 6.02 x 1023 b. How many atoms of nitrogen are in the same amount of ammonia? Use the molar mass to two decimal places found on the periodic table in the front of your

74. ## Economics

Suppose that a tour bus business incurred implicit costs of \$600,000 and explicit costs of \$7 million in a specific year. If the firm sold 125,000 tours at \$60 per person, its accounting: A) profits were \$100,000 and its economic profits were \$500,000. B)

75. ## reimbursement methodologies

does anyone have answers to test 38181803 for penn foster

76. ## algebra

-9 + 36 divided by 6 times 2 -(-6) - 5 +2 = ? I'm having trouble with the order of operations.

77. ## Science.

What did scientist learn from studying Supernova 1987A?

78. ## physics/math

Joe is a former basketball player who is now a work-out junkie, and especially loves to do push-ups. He was a good athlete, but not so good at science in school, especally not good in Physics. He wants you, yes you, to calculate how much work he does, in

79. ## THE METAPHYSICAL CLUB by Louis Menand

I'm taking AP US History so I have a summer assignment. I'm supposed to read The Metaphysical Cub by Louis Menand and write a 4-6 page essay on how the ideas of the past (written about in this book_ effect us today... If anyone has read this book, could

80. ## Physics

A block of mass 8.60 kg is pulled along a horizontal frictionless surface by a cord that exerts a force of 33 N at an angle 29.40 degrees from the horizontal. What is the magnitude of the normal force exerted on the mass by the floor? I solved for the

81. ## Chemistry

In a solution of a weak acid and its conjugate base, which condition has to be true for pH to equal pKa? The concentration of acid has to be greater than the concentration of base. The concentration of acid has to be equal to the concentration of base. An

82. ## Calculus

1/X by first principles

83. ## english

Please help me write an essay. the question is "What do you think the theme is of Our Town and how is it shown?"

84. ## Physics.

What is the transfer mechanism of energy, momentum, and angular momentum?

85. ## grammar

A Superblade was used at the 2 o'clock position, and the anterior chamber was entered was used is a verb ,was entered is also a verb ,am i right

86. ## Thermodynamics

An intrepid explorer takes 400 g of ice from the cold Siberian environment, where the temperature is –40 degrees and places it in a kettle inside his mobile laboratory. The ice melts and he heats the water to +40 degrees. What is the total amount of heat

87. ## chemistry dilutions

you have 47 mL of a 2 M stock solution that must be diluted to .5 M how much water should you add

88. ## math

1) x+8y=33 -x+4y=3 I need help solving this one using the elimination method!

89. ## physics

If you see a lightening bolt, then count 4 seconds until you hear thunder, about how far away was the lightening strike?

Rajen chose a secret number and gave these clues to his friends. the number is even and it is divisible by 3, three times the number is less than 60 but greater than 40. what is Rajen's number?

91. ## geometry

Factor 15x^2 - 8x - 16

92. ## algebra

simplify and write using only positive exponents. thanks. (2x^3y^4)^-2 divided by (8xy^6)^-3

93. ## multimeter

When an AC voltage is being measured across a 15 Ù resistor which is carrying a current of 12 amps, the selector switch should be set to the AC voltage position of

94. ## Chemistry

The solubility of compounds containing the carboxylic acid group can be increased by reaction with a) sulfuric acid b) nitric acid c) sodium hydroxide d) water e) benzoic acid

95. ## Math

Can someone help me solve the following problems using the substituion method? I need to find the ordered pairs and I do not get it.... Here they are 1) 6m+n=47 m-4n=12 2) 6x+4y=-10 -7x+y=57 3) 5x+7y=43 -4x+y=25

96. ## MATH

WRITE A PROPORTIAN THAT IS EQUIVALENT TO THE STATMENT : IF 3 GALLONS OF GASOLINE COST \$5.37, THEN 8 GALLONS WILL COST \$ 14.32.

97. ## Medical

what might be the cause of onset of social fobia in a 19 year old boy?

98. ## Honors Social Studies

Describe the three key concerns that Washington had for the future of the U.S. Explain how the country has progressed in each area and give one specific example. Please see this answer that I just posted for "Samantha."

99. ## English Composition

I am having difficulty writing my essay with collective thoughts that aren't so jumbbled as to the: thesis statement keeping the structure; introduction, body and conclusion.