# danny

Popular questions and responses by danny
1. ## chemistry

In the reaction below, ΔH°f is zero for ___________. Ni(s) + 2CO(g) + 2PF3(g) = Ni(CO)2(PF3)2(l) Ni(s) CO(g) Ni(CO)2(PF3)2(l) both CO(g) and PF3(g) PF3(g)

2. ## chemistry

At a certain elevation, the boiling point of water is 98.5°C. How much energy is needed to heat 35.0 mL of water to the boiling point at this elevation if the water initially was at 23.4°C? (Cp=75.38J/(mol*C), d= 1.00g/mL)

3. ## statistics

A regression analysis between sales (in $1000) and advertising (in$100) resulted in the following least squares line: = 75 + 6x. This implies that if advertising is $800, then the predicted amount of sales (in dollars) is: A)$4875 B) $123,000 C)$487,500

4. ## Physical Science

Energy from the sun reaches Earth mostly by A. conduction. B. convection. C. radiation. D. thermal expansion. I think it's A.

5. ## chemistry

The Ka of hypochlorous acid (HClO) is 3.00×10-8 at 25.0°C. Calculate the pH of a 0.0385 M hypochlorous acid solution. A.1.41 B.7.52 C.-1.41 D.4.47 E.8.94 I chose B

6. ## chemistry

What is the approximate effective nuclear charge for arsenic ?

7. ## Physics

A merry-go-round is a common piece of playground equipment. A 2.4 m diameter merry-go-round with a mass of 300 kg is spinning at 22 rpm. John runs tangent to the merry-go-round at 5.0 m/s, in the same direction that it is turning, and jumps onto the outer

8. ## chemistry

How many calories are required to heat 25.0 g of platinum from 24.5 °C to 75°C (specific heat of platinum = 0.139 J/gK)? 1. 47 cal 2. 42 cal 3. 48 cal 4. 20 cal 5. 80 cal Thank you.

9. ## Physics (Stress & Strain)

A hole 3cm in diameter is to be punched out of a steel plate 8cm thick. The shear stress of the material is 670GPa. What load is required on the punch? 3cm = 0.03m 8cm = 0.08m Lateral surface area (As) = pi*D*h = 3.1416 * .03m * .08m = 3.1416 * .0024m =

10. ## Chemistry

The equation for the complete combustion of ethene (C2H4) is C2H4(g) + 3 O2(g) ==> 2CO2(g) + 2H2O(g) If 2.70 mol C2H4 is reacted with 6.30 mole O2, identify the limiting reagent. show all work.

11. ## chemistry

The enthalpy change for the following reaction is -483.6 kJ: 2H2(g) + O2(g) = 2H2O(g) Therefore, the enthalpy change for the following reaction is _______ kJ: 4H2(g) + 2O2(g) = 4H2O(g)

12. ## Chemistry

As a sample of the radioactive isotope 131 I decays, its half-life a)decreases b)increases c)remains the same

13. ## math

The measures of the three angles of a triangle are given. Find the value of x and state whether the triangle is acute, obtuse, or right. x + 10, x − 20, x + 25 I got x is 55 and it is an acute angle. Is that correct?

14. ## Chemistry

What is the symbol for an ion with 63 protons, 60 electrons, and 88 neutrons? If an ion contains 50 protons, 68 neutrons, and 48 electrons, what is its symbol? Please help me.. im soo lost in this problem!

15. ## Physics

A 225-kg crate is pushed horizontally with a force of 690 N. If the coefficient of friction is 0.20, calculate the acceleration of the crate.

16. ## physics

Two balls have their centers 2.0 m apart. One ball has a mass of m1 = 8.3 kg. The other has a mass of m2 = 5.9 kg. What is the gravitational force between them? (Use G = 6.67 10-11 N · m2/kg2.)

17. ## Algebra 1

a farmer raises chickens and cows. there are 34 animals in all. the farmer counts 110 legs total on these animals. how many chickens and how many cows are on this farm?

18. ## physics

A 100-kg crate, sliding on the floor, is brought to a stop by a 25-n force. What is the deceleration of the crate?

19. ## physics

calculate the horizontal force that must be applied to a 1-kg puck to make it accelerate on a horizontal friction-free air table with the same acceleration it would have if it were dropped and fell freely?

20. ## chemistry

How is the reaction quotient used to determine whether a system is at equilibrium? The reaction is at equilibrium when Q > Keq. At equilibrium, the reaction quotient is undefined. The reaction quotient must be satisfied for equilibrium to be achieved. The

21. ## physics

21. A traffic signal of mass 25.0 kg is suspended by two cables as shown in the diagram below. Solve for the tension in each cable each of the following scenarios: (a) θ1 = θ2 = 20.0°, and (b) θ1 = 20.0°, θ2 = 30.0°.

22. ## Math

Radio stations use three or four letters for their call letters(name). The first letter must be a W or K. How many different call letters are possible if repeated letters are allowed? And not allowed?

23. ## Calculus. I need help!

Write the composite function in the form f(g(x)). [Identify the inner function u=g(x) and the outer function y=f(u).] Then find the derivative dy/dx. y=√sinx √ is square root.

24. ## chemistry

Is the dissolution of borax in water a temperature dependent reaction or is it spontaneous at all temperatures at which water is liquid? I think its spontaneous at all temperatures when water is liquid because borax is a polar compound.

25. ## chemistry

Consider an electrochemical cell based on the reaction: 2H+(aq) + Sn(s) = Sn2+(aq) + H2(g). Which of the following actions would NOT change the measured cell potential? lowering the pH in the cathode compartment addition of more tin metal to the anode

26. ## Chemistry

A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 84.5 kg?

27. ## physics

A highway curve with radius 1000ft is to be banked so that a car traveling 56.0mph will not skid sideways even in the absence of friction At what angle should the curve be banked?

28. ## Velocity

An object is thrown directly downwards from a height of 60m with an initial velocity of 11m/s. What will be its velocity on impact? v^2 = U^2 + 2as a= 9.81m/s^2 u = 11m/s s = 60m v^2 = 11m/s + 2 * 9.81m/s^2 * 60 = 1188.2m^2/s^2 = square root of

29. ## Optics

The famous Chinese magician Foo Ling Yu performs a classic magic trick using a concave mirror with a focal length of 1.6 m. Foo uses the mirror to produce an image of a light bulb that is the same size as the light bulb itself and is at the same location.

30. ## Stress & Strain (Help Please)

A tie bar is made of a material having a tensile strength of 231 MPa and has to carry a load of 255 kN. What id the diameter of the bar if a factor of safety of 7 is applied? ANS = 99.2 mm Cannot figure out how to get the answer. Need help please. Thank

31. ## college algebra

An open box is made from a square piece of cardboard 20 inches on a side by cutting identical squares from the corners and turning up the sides.(a) Express the volume of the box, V , as a function of the length of the side of the square cut from each

32. ## chemistry

Consider an electrochemical cell based on the reaction: 2H+(aq) + Sn(s) = Sn2+(aq) + H2(g). Which of the following actions would NOT change the measured cell potential? lowering the pH in the cathode compartment addition of more tin metal to the anode

33. ## chemistry

Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) gas and calcium hydroxide (Ca(OH)2). If the ΔH for: CaC2(s) + 2H2O(l) = Ca(OH)2(s) + C2H2(g) is -127 kJ, then what is the enthalpy of formation for calcium carbide? The ΔH of formation for

34. ## Math

A spring is 25 cm long when stretched. The spring was stretched by 18% of its original length. Determine the original length.

35. ## math

What is the angle sum of a regular polygon with 7 sides

36. ## Science

Use the word bank below to answer the questions that follow: alleles mitosis DNA phenotype haploid codominance diploid meiosis incomplete dominance centromere reproduce RNA Genes are specific sections of ______________________.

37. ## chemistry

How many electrons does the Au+ ion have ? Enter an integer below without any letters or symbols.

38. ## science

A 5.0 kg model vehicle travelling at 14 m/s experiences a rocket boost of 85 N ( in the direction of motion) for 20 s What is the resulting speed? The answer is 350 but i don't know how to get to that answer

39. ## Physics

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter =

40. ## Physics (Stress & Strain)

What is the factor of safety of a steel hanger having an ultimate strength of 630.000MPa and supporting a load of 65000.000N. The steel hanger in question has a cross sectional area of 5.300cm. ANS = (Round to 3 decimal places) Load = 65000.000N ultimate

41. ## Physics

Camera lenses are described in terms of their focal length. A 50.0 mm lens has a focal length of 50.0 mm (a) A camera with a 50 mm lens is focused on an object 4.0 m away. Locate the image. (b) A 980 mm lens is focused on an object 125 m away. Locate the

42. ## Physics

One of the most powerful cranes in the world, operating in Switzerland, can slowly raise a load of 6000 tonne to a height of 12 m. (1 tonne = 1000 kg) The acceleration of gravity is 9.81 m/s2 . How much work is done by the crane? Answer in units of MJ I

43. ## Chemistry

5F2(g) + 2NH3(g) ==> N2F4(g) + 6HF(g) a)If you have 66.6 g NH3, how many grams of F2 are required for complete reaction? b)How many grams of NH3 are required to produce 4.65g HF? c)How many grams of N2F4 can be produced from 225g F2?

44. ## chemistry

The combustion reaction of acetylene gas is represented by this equation: 2C2H2(g) + 5 O2(g) ==> 4CO2(g) + 2H2O(g) How many grams of CO2 and grams of H2O are produced when 52.0g C2H2 burns in oxygen?

45. ## global

Why would so many women miners prefer to work in the mines without clothing? Why did the women need the heavy belts around their waists and chains between their legs?

46. ## Physics

If the soccer player kicks the ball with an initial velocity of 20 m/s at an angle of 45 degrees relative to the ground then what is the time it takes for the ball to reach the maximum height, what is the time of flight, what is the range, and what are the

47. ## Physics

a 47 kg person in a rollercoaster moving through the bottom of a curved track of radius 47.7 m feels a normal force of 895 N. What is the net centripedal force acting on the person

48. ## Physics

A train traveling at a speed of 110 km/h uniformly decelerates for 20 seconds. During that time it travels 450m. A) What is the acceleration? (m/s^2) B) What is its speed after deceleration? (km/h) A ANS = -.805m/s^2 B ANS = 52km s = 450m t = 20 seconds u

49. ## English 3

Young Goodman Brown is a dynamic character TRUE OR FALSE

50. ## ENGLISH Types of business writing

Assume that you’ve worked for the last five years as an administrative assistant for the Human Resources Department of Broadworth General Hospital. The Director of Human Resources, Miriam Hopkins, has charged you with organizing a two-hour training

51. ## Chemistry

KI+H2SO4 Write the balanced net ionic equation.

52. ## Calculus

A plane flying with a constant speed of 24 km/min passes over a ground radar station at an altitude of 8 km and climbs at an angle of 20 degrees. At what rate, in km/min, is the distance from the plane to the radar station increasing 2 minutes later?

53. ## Math Trigonometry

A plane flies in a direction of 85° from Chicago. It then turns and flies in the direction of 200° for 150 miles. It is then 195 miles from its starting point. How far did the plane fly in the direction of 85°? I am confused about aereal navigation. Can

54. ## chemistry

Which element is reduced in the unbalanced reaction below? I− + MnO4− + H+ = I2 + MnO2 + H2O I no reduction occurred in this reaction O H Mn

55. ## Physics (Stress & Strain)

A uniform bar 1.900 meters in length and having a cross sectional area of 11.000cm^2 is subject to a loading of 5450.000 Newtons. this load causes an extension to the bar length of 2.420mm. Calculate the stress and strain produced. 11cm = .11m 2.420mm =

56. ## Acceleration

Which of the following statements about acceleration is true. Acceleration is: A) time/ velocity B) force/ time C) the rate of change of displacement D) time/ force E) the result of an unbalanced force exerted on a body. ANS = E Is this correct??

57. ## Math

it costs $175 to rent a jet ski for 2 hours. it costs$300 to rent a jet ski for 4 hours. write an equation that represents y (in dollars) of renting a jet ski for x hours.

58. ## statistics

In a one-way ANOVA, there are three independent samples, with n1 8, n2 = 10, and n3 = 7. The calculated F-statistic is F = 3.95. At the 0.05 level of significance, what conclusion would be reached? Based on the F distribution tables, what is the most

59. ## math

A car is sold for $22,000. After one year, the value of the car is$16,500. Write an exponential function y to determine the value of the car after x years if the rate of decrease is the same each year.

60. ## Economics Macro

Suppose that real GDP per capita in the United States is $49,000. If the long-term growth rate of real GDP per capita is 1.6% per year, how many years will it take for real GDP per capita to reach$98,000?

61. ## Algebra 2

Amanda surveyed 20 juniors and seniors at Delamar high school to find the number of hours per week they spend working at part-time jobs. Her results are shown below. Juniors: 20,10,20,10,15,0,0,10,20,15 Seniors: 20,20,10,10,0,0,0,10,0,10 which statement

62. ## HELP! HELP! HELP! Physics

The surface density of a thin rectangle varies as: σ(x,y)= 14.0 kg/m2 + 9.00 kg/m4(x2+y2) The rectangle has a length L = 0.500 m and a width W = 1.500 m. Calculate Iz, the moment of inertia about the z-axis.

63. ## grammar

Which part of speech is the capitalized words in this sentence? Four score and seven years ago our fathers brought forth on this continent, a NEW nation, conceived in Liberty, and DEDICATED to the proposition that all men are created equal. Now we are

64. ## Physics

Simple Machines A simple wheel and axle has a wheel diameter of 2.3m and an axle diameter of 92mm. If an effort of 26N is required to raise a mass of 16 kg what is the efficiency of the machine? A- 2.46% B- 95.3% C- 24.1% D- 20.1% E- 65.5% I am having a

65. ## Physics

A Body with a mass of 150kg is located at a height of 45 m. If allowed to fell freely to the ground. What will be its velocity on impact? KE= 1/2*m*v^2 PE= m*g*h 1/2*m*v^2= m*g*h 1/2*150kg*45m*v^2= 150kg*9.81*45m 3375* v^2= 66217.5 3375*v^2/3375=

66. ## math

A steel tube has an outside diameter of 15 cm, an inside diameter of 13 cm,and is 3.7 m long. What is the volume of the steel contained in the tube in cubic cm is?

67. ## Math

Frank has 3 nickels, 5 dimes, and 2 quarters. What is the range, mean, median, and mode of the values of Frank's coins?

68. ## math

If the radius of this cylinder is doubled, its volume will be twice as much four times as much eight times as much is it four times as much?

69. ## english

"The editors . . . break those sequences up into quick jagged shots that key us up and keep us hyper-alert . . . we look hard at the screen to take it in." universality?

70. ## Physic

A 2.2 m-long string is fixed at both ends and tightened until the wave speed is 50 m/s. What is the frequency of the standing wave shown in the figure? Answer in Hz. I've been working on it for a while but cant figure out...

71. ## Pre-Calculus

A hemispherical bowl with a 30-centimeter radius contains some water, which is 12 centimeters deep. Find the volume of the water.

72. ## math

Sarah Meeham blends coffee for Tasi-Delight. She needs to prepare 140 pounds for blended coffee beans selling for $5.07 per pound. She plans to do this by blending together a high-quality bean costing$6.50 per pound and a cheaper bean at \$2.50 per pound.

73. ## chem

The value for ΔH° for the reaction below is -72 kJ. How many kJ of heat are released when 1.0 mol of HBr is formed in this reaction? H2(g) + Br2(l) = 2HBr(g)

74. ## chemistry

Calculate the H3O+ concentration present in water under the following conditions. Enter your answer in scientific notation. a. [OH-] = 2.8 x 10-7 M b. [OH-] = 8.8 x 10-3 M c. [OH-] = 2.4 x 10-11 M everytime I do the problem In the calculator I get system

75. ## Spanish

¿Con quién _____ tú el almuerzo? A. comparto B. compartes C. compartimos D. comparte B?

76. ## Physical Science

When opposite poles of two magnets are brought together, the poles A. attract each other. B. repel each other. C. cancel each other. D. cause a net force of zero. I think it's B.

77. ## Acceleration

Which of the following statements about acceleration is true. Acceleration is: A) time/ velocity B) force/ time C) the rate of change of displacement D) time/ force E) the result of an unbalanced force exerted on a body. ANS = E Is this correct??

78. ## math

The only defined term of those listed is: line angle plane point

79. ## math

Find the exact circumference of a circle with diameter equal to 8 ft. 8 ft. 16 ft. 64 ft. what equation would u use?

80. ## english

Which of the following topics relate directly to a work's authenticity? 1)believability of characters 2)the appeal of a certain guitar riff 3)sincerity expressed in a love song 4)the likely appeal to all teenagers 5)the way the setting matches the mood of

81. ## english

"He manages to portray tiny, random events as significant without the occasionally overblown melodrama . . . " so im suppose to Read the quote and choose its category. but i don't no what to do? these are my answer choices.. -universality -subject matter

82. ## english

An example of the frame story is _____. 1)"The Celebrated Jumping Frog of Calaveras County 2"The Lady, or the Tiger?" 3)"The Necklace" i think its number 1?

83. ## Statistics

What are the mean and standard deviation of the sampling distribution of ​? Round your results to the nearest penny.

84. ## chemistry

One of the ways to produce iron is to take iron(II) oxide and react it with carbon monoxide to get pure iron and carbon dioxide. The reaction is FeO(s) + CO(g) = Fe(s) + CO2(g). What is the partial pressure of CO2(g) if 2.00 atm of CO and excess iron(II)

85. ## Chemistry

Calculate the pH of a solution in which a. [H3O+] = 7.8 x 10-7 M pH = b. [H3O+] = 5.1 x 10-6 M pH = c. [H3O+] = 6.1 x 10-5 M pH = d. [H3O+] = 9.3 x 10-4 M pH = I get 8.1 9.5 9.1 6.7 but its wrong please someone help!

86. ## calculus

Imagine making a tent in the shape of a right prism whose cross-section is an equilateral triangle (the door is on one of the triangular ends). Assume we want the volume to be 2.2 m3, to sleep two or three people. The floor of the tent is cheaper material

87. ## Physics

A steel bar has a rectangular cross section measuring 1.000cm by 2.900cm and is 8.700m in length. A load of 189000.00N causes the bar to extend 1.500mm. Calculate the stress and strain produced. ANS 1 = kPa (3 decimal places) ANS 2 = (6 decimal places)

88. ## physics

Tom has a mass of 69.0 kg and Sally has a mass of 54.0 kg. Tom and Sally are standing 20.0 m apart on the dance floor. Sally looks up and sees Tom. She feels an attraction. If the attraction is gravitational, find its size. Assume that both Tom and Sally

89. ## math

Two similar polygons have areas of 16 square inches and 64 square inches. The ratio of a pair of corresponding sides is 1/4. True False its true?

90. ## math

When chords intersect in a circle, the vertical angles formed intercept congruent arcs. always sometimes never

91. ## english

"All the world is a stage, and all the men and women merely players." metaphor?

92. ## Chemistry

Identify the solvent and the solute in vinegar, a dilute aqueous solution of acetic acid.

93. ## Math

Gabriella’s travel shampoo bottle holds 1/2 cup of shampoo before leaving on vacation she filled the bottle to the top with 1/8 cup of shampoo how much shampoo was already in the bottle?

94. ## Maths

Have a question on complex numbers. Z1= 1+j2, Z2= 2+j5 Find total impedance in Cartesian and polar form of two impedances in parallel: 1/ZT = 1/Z1 + 1/Z2 I get to 39/58 + 83/58 j but then get a bit lost.

95. ## physics

How many kilometers would you have to go above the surface of the earth for your weight to decrease to 39{\rm \\%} of what it was at the surface? Express your answer using two significant figures.

96. ## physics

What is the mass of 5.00L of pure water?

97. ## spanish

Nosotros siempre _____ la comida. A. comparten B. comparto C. compartimos D. comparte A?

98. ## Physical Science

Which of the following is a heterogeneous mixture? A. water in a swimming pool B. sugar water C. a jar of mixed nuts D. stainless steel I think it's B.