# christina

Popular questions and responses by christina
1. ## Chemistry

What is the ionic and net ionic equation for Na2CO3 + 2 HNO3 -> 2 NaNO3 + H2O + CO2 (g) This is what i have so far... Na2(aq)+CO3+H+NO3 -> Na+ NO3+ H2O(l)+CO2(g)... i don't know what to do!!!

2. ## Calculus

Suppose f(pi/3) = 3 and f '(pi/3) = −7, and let g(x) = f(x) sin x and h(x) = (cos x)/f(x). Find the following. a. g'(pi/3) b. h'(pi/3)

3. ## Algebra

The back of Tom's property is a creek. Tom would like to enclose a rectangular area, using the creek as one side and fencing for the other three sides, to create a corral. If there is 100 feet of fencing available, what is the maximum possible area of the

4. ## Calculus

The number N of US cellular phone subscribers (in millions) is shown in the table. (Midyear estimates are given.) t 1996 1998 2000 2002 2004 2006 N 44 69 109 141 182 233 (a) Find the average rate of cell phone growth between the following years. In each

5. ## College Chemistry

Suppose there are two known compounds containing the generic elements X and Y. You have a 1.00-g sample of each compound. One sample contains 0.29 g of X and the other contains 0.38 g of X. Identify plausible sets of formulas for these two compounds. Check

6. ## Chemistry

A 2.52g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 4.36g of CO2 and 0.892g of H20. Another sample of the same compound of mass 4.14g, yielded g of SO3. A third sample, of mass, 5.66g,

7. ## science (chem)

For the preparation and standardization of NaOH with KHP im supposed to boil water for 1hr and 30 min to remove CO2....the problem is that if I don't boil it for that long and (30 min) b/c of not enough time but I put the water I boiled for 1/2 hr

8. ## Geography

Which of the following most accurately describes the difference between climate and weather? (1 point) Climate refers to long-terms conditions; weather refers to daily conditions. Climate refers to severe weather events; weather refers to precipitation.

9. ## AP Chemistry

CH3NH2(aq)+H2O(l)=>CH3NH3+(aq)+OH-(aq) Kb=4.4 x 10^-4 Methylamine, CH3NH2, is a weak base that reacts with water according to the equation above. A student obtains a 50.0 mL sample of a methylamine solution and determines the pH of the solution to be

10. ## physics

An automobile tire is rated to last for 45,000 miles. Estimate the number of revolutions the tire will make in its lifetime.

11. ## Chemistry

The percent composition by mass of an unknown compound with a molecular mass of 60.052 amu is 40.002% C, 6.7135% H, and 53.284% O. Determine the compound's empirical and molecular formulas.

12. ## physics

Find the linear speed of the bottom of a test tube in a centrifuge if the centripetal acceleration there is 5.5×104 times the acceleration of gravity. The distance from the axis of rotation to the bottom of the test tube is 8.0 .

13. ## Physics

A small block on a frictionless horizontal surface has a mass of 2.50×10−2 Kg. It is attached to a massless cord passing through a hole in the surface. The block is originally revolving at a distance of 0.300 m from the hole with an angular speed of

14. ## Physics -Interference & Diffraction

Given Information: Light of wavelength 631 nm passes through a diffraction grating having 485 lines/mm. Part A: What is the total number of bright spots (indicating complete constructive interference) that will occur on a large distant screen? *Answer: 7

15. ## Physics

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According to one set of

16. ## physics

You push a 45 kg wooden box across a wooden floor at a constant speed of 1.0 m/s. The coefficient of kinetic friction is 0.15. Now you double the force on the box. How long would it take for the velocity of the crate to double to 2.0 m/s?

17. ## Chemistry

You have a solution of 0.500 M NaCl. If you add an equal amount of water to this solution, doubling the volume, what is the concentration of this solution?

18. ## Chemistry

Rank the following in order of increasing bond polarity: H-F, H-Br, F-F, Na-Cl. Is it this....? F-F, H-Br, H-F, Na-Cl

19. ## geography

compare latin america's landmass and population to those of the united states. Based on that data, how might the overall population densities of the two compare?

20. ## history

What is the relationship between the ruling class and warrior class in Japan and Europe? I know that in Japan the Samurais were the warrior and ruling class till the Edo period right? but what about Europe?

21. ## Calculus

The area A of the region S that lies under the graph of the continuous function is the limit of the sum of the areas of approximating rectangles. A = lim n → ∞ [f(x1)Δx + f(x2)Δx + . . . + f(xn)Δx] Use this definition to find an expression for the

22. ## Physics

A boat is being towed through a canal by means of ropes which make a 45 degree angle to each other. If a force of 75N is applied to the rope, what is the resultant force pulling the boat forward?

23. ## Geography

Which of the following are impacts that the temperate climate has had on Georgia’s development? (1 point) encouraging crops with longer growing seasons drawing immigrants from other locations encouraging tourism all of the above 3. What impacts have

24. ## Social Studies

1. Diversity most closely means (1 point) sharing cultural traits and practices with others. making up a whole of many different parts. being a member of a small ethnic group. having many similar regions next to one another. 2. How does life in Istanbul

25. ## statistics

Use the random-number table to simulate the outcomes of tossing a quarter 25 times. Assume that the quarter is balanced (i.e., fair). (Start at row 1, and let 0, 1, 2, 3, 4 indicate heads and 5, 6, 7, 8, 9 indicate tails. Enter H for heads and T for tails,

26. ## Chemistry

Calculate the boiling point elevation of a solution made from 15.0 g of a nonelectrolyte solute and 250.0 g of water. the molar mass of the solute is 50.0 g and Kb = 0.51 degrees C/m

27. ## Ap physics B

Four positive charges are fixed at the corners of a square, as shown above. Three of the charges have magnitude Q, and the fourth charge has a magnitude 2Q. Point P is at the center of the square at a distance r from each charge. 22. What is the electric

28. ## geometry

a spherical water storage tank has a radius of 10ft. A cubic foot of water is about 7.5 gallons. How many gallons of water will the tank hold?

29. ## math

a peanut butter jar has a height of 5.9in and diameter of 3.6 in. one cubic inch holds 0.45 oz of peanut butter. How many ounces will fit in the jar

30. ## Geography

What role did the waterways of Europe play in the development of it's economy?

31. ## Physics

A stuntman sitting on a tree limb wishes to drop vertically onto a horse galloping under the tree. The constant speed of the horse is 10.0 m/s, and the man is initially 2.75 m above the level of the saddle. (a) What must be the horizontal distance between

32. ## science( chem)

When 100.0ml of a weak acid was titrated with 0.09381M NaOH, 27.63ml were required to reach the equivalence point. The pH at the equivalence point was 10.99. What was the pH when only 19.47ml of NaOH had been added ? I'll just post my work and I need

33. ## math

Alex came home after school one day and found that his mother had left a plate of cookies. Alex ate 1/4 of the cookies. When his sister Bernice came home, she ate 1/3 of the remaining cookies, and when Carla came home, she ate 1/2 of the cookies on the

34. ## calculus

Find the limit. Use l'Hospital's Rule if appropriate. If there is a more elementary method, consider using it. lim x→∞ {(5x − 4)/(5x + 3)}^5x + 1

Write a paragraph describing your attitudes toward writing. Use the following steps. Prewrite: Jot down a few of the words that come to mind when you think of writing. Think of any significant experiences you have had that have shaped your attitude toward

36. ## Chemistry

The Cu2+ ion can be separated from Ag+, Ca2+, and K+ in aqueous solution by 1. precipitation of Cu2+ as Cu(OH)2(s) with 6 M NaOH(aq). 2. precipitation of Ag+, Ca2+, and K+ as the carbonates. 3. None of these procedures will separate Cu2+ from the other

37. ## math

At Strawberry State College, the ratio of females to males is 2:1. If there are 2100 students, how many are female and how many are male?

38. ## science

You measure the dimensions of a rectangular block of aluminum to determine its volume. It has the following dimensions. length = 10.27 cm; width = 4.92 cm; height = 1.53 cm Assuming that each of these measurements is accurate to the nearest 0.01 cm, find

39. ## Physics

A 0.5 kg wooden block is dropped from a height of 15 m. At what height must a 5g bullet be traveling upward strike the block in order to momentarily stop its fall? Assume that the time required for the bullet to come to rest in the block in negligibly

40. ## math

Maude uses 3/4 of her allowance to get a massage for 3/5 of an hour. What fraxction of her allowance would she need to get a massage for a full hour?

41. ## Algebra

Find the linear function with the following properties: f(0)=1 and the slope of f equals -3/2 THANK YOU

42. ## Physics

Suppose we take a 1 m long uniform bar and support it at the 27 cm mark. Hanging a 0.31 kg mass on the short end of the beam results in the system being in balance. Find the mass of the beam.

43. ## science( chem)

For the lab of Determining the % of iron in an iron ore sample The instructions were to: 1) Weigh out btw 0.3-0.4g of iron ore 2) disolve in concent HCl (10ml) and 3ml of 0.25M SnCl2 3) add enough tin so the yellow color disapeared 4) heat until sample

44. ## Physics

A CD rotates at 500 (revolutions per minute) while the last song is playing, and then spins down to zero angular speed in 2.60 seconds with constant angular acceleration. The magnitude of the angular acceleration of the CD, as it spins to a stop is 20.1

45. ## Finance

Ngata Corp. issued 12-year bonds 2 years ago at a coupon rate of 8.4 percent. The bonds make semiannual payments. If these bonds currently sell for 105 percent of par value, the YTM is ? percent

46. ## Statistics

A random sample of 100 cable TV movies contained an average of 3.38 acts of physical violence per program. At the 99% level what is your estimate of the population value? mean = 3.38 s = 0.30 N = 100

47. ## math

Jacob opens a savings account on January 1 with a deposit of \$350. He has "direct deposit," in which \$25 is deposited every other week. The bank also charges a \$3 monthly processing fee. How much money will he have at the end of the year?

48. ## Physics

Here's the question: A 55 kg swimmer is standing on a stationary 235 kg floating raft. The swimmer then runs off the raft horizontally with a velocity of +4.3 m/s relative to the shore. Find the recoil velocity that the raft would have if there were no

49. ## science (chem)

what is the chemical eqzn of Na2CO3 + HClO4? Na2CO3 + HClO4 ==> NaClO4 + H2O + CO2 I will leave it for you to balance. how did you get that DrBob The rule on carbonates is: An acid added to a carbonate yields carbon dioxide, water, and a salt. oooh so you

50. ## Science

In the early 1900s, Alfred Wegener noticed that some of the Earth's continents looked like they might fit together like a jigsaw puzzle. He also observed that the continents that looked like they fit together had similar plants, animals, and rock

51. ## stats.

The GMAT test is required for admission to most graduate programs in business. In a recent year, the GMAT test scores were normally distributed with a mean of 550 and standard deviation of 100. A. Find the first quartile for the distribution of GMAT

52. ## math final review (help)

from a 12cm by 12cm piece of cardboard, square corners are cut out so that the sides can be folded up to make a box. Express the volume of the box as a function of the length, x, in centimeters.

53. ## Science

The sensitivity of a measuring instrument is the value of the smallest quantity that can be read or estimated with it. What is the smallest part of a centimeter that can be read with the following? (a) a meterstick with markings at each millimeter I tried

54. ## Chemistry

Chlorine gas may be easily prepared in the lab according to the reaction: 2KMnO4(s)+ 16HCl(aq)-> 2 MnCl2(aq)+5Cl2(g)+ 8H2O(l)+ 2KCl(aq) What mass of HCl is needed to prepare 1 mole of Cl2 gas?

55. ## Chemistry

Given the Empirical formula: C6H7N, and a molecular mass of 372.52 g/mol, How do I find the MOLECULAR formula for the compound?

56. ## geometry

how many milliliters of soup will this hemispherical bowl hold?(1cm cubed holds 1mL) Radius= 7 cm

57. ## chemistry

The mineral CaF2 has a solubility of 2.1 x 10^-4 M. What is the Ksp of CaF2? a. 1.85x10^-11 b. 9.3x10^-12 c. 3.7x10^-11 d. 8.8x10^-3

58. ## math

a steel cargo container is shaped like a cube measuring 5.2ft on each edge. How much steel is needed to make this container?

59. ## science( chem)

Find the pH of a solution prepared by disolving 1.00g of glycine amide hydrochloride (BH+) (mwt=110.54g/mol) plus 1.00g of glycine amide (B)(mwt=74.08) in 0.10L PKa=8.04 I got pH= 8.21 Is that correct? This question actually has 4 extra parts but I wanted

You decide to use your body as a Carnot heat engine. The operating gas is in a tube with one end in your mouth (where the temperature is 37.0 C) and the other end at the surface of your skin, at 30.0 C. What is the maximum efficiency of such a heat engine?

61. ## Physical Science

If you were to expend 10 Joules of work to push a 1-coulomb charge against an electric field, what would be its voltage with respect to its voltage in its starting position? When released, what will be its kinetic energy if it flies past its starting

62. ## Physics -I'm stumped

Europa, a satellite of Jupiter, appears to have an ocean beneath its icy surface. Proposals have been made to send a robotic submarine to Europa to see if there might be life there. There is no atmosphere on Europa, and we shall assume that the surface ice

63. ## science(chem)

What is Zimmerman Reagent made of? (I know it is acidic b/c I was told after it burned a hole in my jeans) acid? You must mean Zimmermann-Reinhardt reagent (79 g MnSO4, 100 mL of concentrated H2SO4, and 200 mL of concentrated H3PO4, diluted to 1 L)

64. ## Statistics

you create the data create a set of seven numbers (repeats allowed) that have the five numbers summary. minimum =4 Q1=8 M=12 Q3=15 Maximum=19. There is more than one set of seven numbers with this five number summary. What must be true about the seven

65. ## Physics -Compton Scattering

QUESTION 1: Calculate the maximum increase in photon wavelength that can occur during Compton scattering. = ??? pm QUESTION 2: What is the energy (in electron volts) of the smallest-energy x-ray photon for which Compton scattering could result in doubling

66. ## Physics

Calculate the specific heat of a metallic element if 314 joules of energy are needed to raise a 50.0 g sample from 25 to 50 degress C ? :)

67. ## Physics

You're using a rope to pull a sled at constant velocity across level snow,with coefficient of kinetic friction 0.050 between sled and the snow. The sled is loaded with physics books, giving a total mass of 23 kg . A) With what force should you pull with

68. ## algebra

You deposit \$3000 in an account earning 7% interest compounded continuously. The amount of money in the account after years is given by A(t)=3000 e^(0.07 t) . How much will you have in the account in 5 years? \$ Round your answer to 2 decimal places. How

69. ## geometry

jo was comparing two cylinders that both had a radius of 5cm. the first had a height of 10cm, and the other a height of 20cm. How many times greater was the volume of the larger cylinder?

70. ## chemistry

given the reactant amounts specified in each chemical eguation, determine the limiting reactant in each case: a. HCL+NaOH->NaCl+H2O 2.0 mole of HCl 2.5 mole NaOH b. Zn+2HCl->ZnCl2+H2 2.5 mole Zn 6.o mole HCl c. 2Fe(OH)3+3H2SO4->Fe2(SO4)3+6H2O 4.0 mole

71. ## maths

how do you write 2.089 in expanded form

72. ## medical billing

for medicaid cases there is no assignment of benefits unless the patient has other insurance in addition to medical. true or false 2. a two or three form that incorporates a bill, insurance form,and routing document used both computer and paper based

73. ## Finance

You have found the following stock quote for RJW Enterprises, Inc., in the financial pages of today's newspaper. The closing price for this stock that appeared in yesterday's paper was \$ (Do not include the dollar sign (\$). Round your answer to 2 decimal

74. ## Math URGENT!!

The speed of a runner increased steadily during the first three seconds of a race. Her speed at half-second intervals is given in the table. Find a lower estimate for the distance that she traveled during these three seconds. t(s) 0 0.5 1.0 1.5 2.0 2.5 3.0

75. ## math

Ann and Bob are cycling on a track. Ann completes one lap every 15 seconds, and Bob completes one lap every 18 seconds. When will Ann lap Bob, assuming that they started together?

76. ## Physics

A test rocket is launched by accelerating it along a 200.0-m incline at 1.25m/s2 starting from rest at point A (the figure (Figure 1) .) The incline rises at 35.0 ∘ above the horizontal, and at the instant the rocket leaves it, its engines turn off and

77. ## math

a bowling ball has a diameter of 8.4 in. It is made of plastic that weighs 0.05lb/in cubed.Find the weight of the bowling ball

78. ## Chemistry

A sealed flask contains 1 mole of hydrogen and 3 moles of helium gas at 20DC. If the total pressure is 40kPa, what is the partial pressure of the Hydrogen gas? AND :) The data below was obtained by a student in order to determine the percent of water in a

79. ## physics

Can the value of equilibrant be equal to zero? If yes, why?

80. ## math

If you are flying to a city 800 miles away, what will be the difference in flight times between flying into a 40-mph headwind and flying with a 40-mph tailwind if the plane's maximum speed with no wind is 160 mph?

81. ## chemistry

A lab tech had accidentally set out 16M HCl for this experiment. How much ( in mL) 16M HCl is needed to make 450mL of a 3M HCl solution?

82. ## Physics

An explorer in the dense jungles of equatorial Africa leaves his hut. He takes 41 steps at an angle 45∘ north of east, then 81 steps at an angle 60∘ north of west, then 49 steps due south. Assume his steps all have equal length. Save him from becoming

83. ## math

The GCF of two numbers is 15. Their LCM is 450. What are the two numbers? (Enter your answers as a comma-separated list.)

84. ## math

A manufacturer sells widgets, each of which is packaged in a box whose dimensions are 8 centimeters by 8 centimeters by 8 centimeters. Design the dimensions of a box to ship widgets. Your box must hold at least 1000 widgets. (Enter your answer in the form

85. ## science/math

A car traveling at the speed of 30.0 m/sec encounters an emergency and comes to a complete stop. how much time will it take for the car to stop if its rate of deceleration is -4.0 m/sec

86. ## geography

how are the andes of south america similar in location to the rocky mts.?

87. ## math

On a TV game show, a contestant makes \$800 for every correct answer but loses \$500 for every wrong answer. After answering 26 questions, Sarah broke even. How many questions did she answer correctly?

88. ## Science.

Whats the difference between a scientific theory and a regular theory? A theory may be about anything but a scientific theory is designed to explain some scientific principle. Why people shop at a certain store might be an ordinary theory but why AgCl is

89. ## Chemistry

Of what value is knowledge of density to a chemist?

90. ## Physics

It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.20 m). As one goes deeper and deeper in the ocean, the pressure increases by 1.0*10^4 Pa for every meter below the surface. If a diver goes down 33.0 m (a bit

91. ## Physics

A test rocket is launched by accelerating it along a 200.0-m incline at 1.25m/s2 starting from rest at point A (the figure (Figure 1) .) The incline rises at 35.0 ∘ above the horizontal, and at the instant the rocket leaves it, its engines turn off and

92. ## chemistry

Suppose that the microwave radiation has a wavelength of 12 cm . How many photons are required to heat 255 mL of coffee from 25.0 ∘C to 62.0 ∘C? Assume that the coffee has the same density, 0.997 g/mL , and specific heat capacity, 4.184 J/(g⋅K) , as

93. ## Chemistry

What would happen to the color of a dilute solution containing FeCL4 if you added concentrated HCl?

94. ## Physics

To strengthen his arm and chest muscles, an 83.0 kg athlete 2.00 m tall is doing a series of push-ups. His center of mass is 1.15 m from the bottom of his feet, and the centers of his palms are 30.0 cm from the top of his head. Find the force that the

95. ## geometry

when two lines intersect, they form two pairs of "opposite" angles called _________ angles?

96. ## chemistry

Calcium carbonate reacts with hydrochloric acid according to the following reaction: CaCO3 (s) + 2 HCl (aq) --> CaCl2 (aq) + H2O (l) + CO2 (g) How many grams of calcium carbonate would be required to neutralize 50.0 cm3 of 8.00 M HCl?

97. ## Physics

Oxygen (O2) has a molar mass of 32.0 g/mol [.032kg/mol]. What is the root-mean-square speed of an oxygen molecule at a temperature of 310 K? Vrms=492 m/s What is its average translational kinetic energy at that speed? Kav= ?? J I am having problems with

98. ## math bus 105

Calculate (a) interest and maturity value, (b) discount period, (c) bank discount, and (d) proceeds. Assume ordinary interest. (Round answers to nearest hundredths) Date of note Face value Length of note Interest rate Bank discount rate Date of discount