# Luke

Popular questions and responses by Luke
1. ## Chemistry

Use an enthalpy diagram to calculate the lattice energy of CaCl2 from the following information. Energy needed to vaporize one mole of Ca(s) is 192 kJ. For calcium, the first IE = 589.5 kJ mol-1, the second IE = 1146 kJ mol-1. The electron affinity of Cl

2. ## math

Find (A upside down U B) upside down U C, given A = {s,e,t} B = {m,E} C = {f,r,e,e,}

3. ## vectors

Express the unit vectors iˆ, jˆ, and kˆ as ordered triples and show that: a) iˆ x jˆ = kˆ b) kˆ x jˆ = -iˆ To begin, I subbed in iˆ= (1,0,0) jˆ= (0,1,0) kˆ = (0,0,1) for a) I got (0,-1,1) = (0,0,1) after crossing i x j What do I do next?

4. ## Statistics

A roulette wheel has 38 slots, numbered 0, 00, and 1 to 36. Two slots are green, 18 of the others are red, and 18 are black. a) What is the probability of winning with a bet on red in a single play of roulette? b) You decide to play roulette 4 times, each

5. ## math

a spinner wheel with 3 color choices red, blue, and yellow) is spun and a 4 sided die I rolled. list the possible outcomes described in the situation.

6. ## Math

And angle measures 53° what are the measures of the angles complement and supplement a complement 37° supplement 137° be complement 127° supplement 47° C complement 37° supplement 127° D complement 127° supplement 37° my answer is B is that right

7. ## english essay

The second poem I will write about is ‘the conscript’ it was written by Wilfred Gibson in 1917. a law was passed to force men to join up between the ages of 18-41 unless they were ill this poems says what you’re really going to expect from the war if

8. ## Maths

Make h subject of formula in A=πr√h²-r²

9. ## math

what is the answer to the math pizzazz E-30? What is the title?

10. ## Chem

How much methane, in grams, must be burned to release 542 kJ of heat? H=-802kJ

11. ## Statistics

The probability of Joe is at work is 49%. The probability Joe is at home is 25%. What is the probability Jow is neither at Work nor at home? A) 39% B)74% C)52% D)26% I get the answer at about 38%,but doesn't round to 39%, can anyone help, I'm stuck.

12. ## Physics

In a common test for cardiac function (the "stress test"), the patient walks on an inclined treadmill (Figure 6-46). Estimate the power required from a 70 kg patient when the treadmill is sloping at an angle of 15° and the velocity is 3.10 km/h.

13. ## Vectors

A boat heads 15 degrees west of north with a water speed of 3 m/s. Determine its velocity relative to the ground when there is a 2 m/s current from 40 degrees east of north.

14. ## probability

consider a sequence of independent tosses of a biased coin at times k=0,1,2,…,n. On each toss, the probability of Heads is p, and the probability of Tails is 1−p. A reward of one unit is given at time k, for k∈{1,2,…,n}, if the toss at time k

15. ## Super Easy Math Question

3x^2-12x+11=0 Solve for x.

16. ## Geometry

How do you divide a hexagon into 9 congruent parts?

17. ## science

which kind of inclined plane pushes up more steeper or flatter? what do you think causes this?

18. ## Physics

Two buckets of sand hang from opposite ends of a rope that passes over an ideal pulley. One bucket is full and weighs 110 N ; the other bucket is only partly filled and weighs 65 N . You release the lighter bucket and the heavier one descends. What is the

19. ## Chemistry

How many milliliters of O2 are consumed in the complete combustion of a sample of hexane, C6H14, if the reaction produces 325 mL of CO2? Assume all gas volumes are measured at the same temperature and pressure. The reaction is 2C6H14(g) + 19O2(g) ->

20. ## Calculus

find d^2y/dx^2 (second derivative) for y=cos^2 4x

21. ## physics

What is the minimum work needed to push a 950 kg car 890 m up along a 8.0 degree incline? Assume the effective coefficient of friction retarding the car is 0.22.

22. ## physics

a remote controlled car's wheel accelerates at 22.4 rad/s^2. if the wheel begins with an angular speed of 10.8 rad/s what is the wheel's angular speed after exactly 3 full turns?

23. ## math

how does a rodeo star get around?

24. ## Chemistry

A solution of acetic acid, CH3COOH, has a concentration of 0.218 M and a density of 1.00 g mL-1. What is the molality of this solution?

25. ## more statistics

The percent of fat calories that a person in America consumes each day is normally distributed with a mean of 36 and a standard deviation of about 10. Suppose that 16 individuals are randomly chosen for an experiment. Completely describe the distribution

26. ## Physics

A rock is thrown straight up at 22.0 m/s from a roof of a 30.0 m tall building. After rising, the rock falls on the street below. Ignoring air resistance, how much time is the rock in the air? Show the work please :)

27. ## math

If y varies directly as the square root of x and y = 47 when x = 49, find y if x = 2401. (Round off your answer to the nearest hundredth.)

28. ## science

Which physical properties are characteristics of metals? Choose all that apply. -brittle -high luster -malleable -ductile -not very reactive 1, 2, and 5?

29. ## chemistry

Consider the reaction at equilibrium: 2NO2(g) N2O2(g) + O2(g) for which, H = −20.4 kJ · mol−1. If you decrease the temperature of the system, what will occur?

30. ## Physics

A 2.90 kg mud ball has a perfectly inelastic collision with a second mud ball that is initially at rest. The composite system moves with a speed equal to one-third the original speed of the 2.90 mud ball. What is the mass of the second mud ball?

31. ## Calculus

Find two positive numbers that satisfy the given requirements. The product is 147 and the sum of the first number plus 3 times the second number is a minimum.

32. ## college physics

How many revolutions per minute would a 18 m-diameter Ferris wheel need to make for the passengers to feel "weightless" at the topmost point?

33. ## 11th grade visual art

first of all this is my first time so i don't know if i am doing it right. I need help i have holiday homework that i need to do but i cant find good enough info for question 1 and i don't understand how to do question 2 below i will write homework

34. ## Math

What will be the luck numbers 5 out 90 at a given period of time?

35. ## chemistry

Suppose that the microwave radiation has a wavelength of 12 cm . How many photons are required to heat 295 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

36. ## vectors

A 35-kg trunk is dragged 10 m up a ramp inclined at an angle of 12º to the horizontal by a force of 90 N applied at an angle of 20º to the ramp. At the top of the ramp, the trunk is dragged horizontally another 15 m by the same force. Find the total work

37. ## vectors

Find any vector w that is perpendicular to both u = 3j + 4k and v = 2i. i, j, k are basis vectors. Textbook answer: (0,4,-3) My attempt: used any scale factor variation, like 4j-3k or -8j+6k to get w=8j-6k How do i solve this the longer way?

38. ## vectors

Upon reaching a speed of 215 km/h on the runway, a jet raises its nose to an angle of 18º with the horizontal and begins to lift off the ground. a. Calculate the horizontal and vertical components of its velocity at this moment. b. What is the physical

39. ## chemistry

1. Silicon dioxide reacts with carbon upon heating to produce silicon carbide (SiC) and carbon monoxide. SiO2(s) + 3C(s) = SiC(s) + 2CO(g) a. What mass of carbon is required to react completely with 15.70 g of SiO2? b. When 152 g of SiO2 reacts with excess

40. ## Physics

5. A grating with 400 lines per mm is illuminated with light of wavelength 600.0 nm. (a) Determine the angle at which the maxima are observed (b) Determine the largest order (n) that can be seen with this grating and this wavelength.

41. ## Maths

Two tetrahedral dice are thrown; one is red and the other is blue . The number on which each lands is noted, the faces being marked 1,2,3,4. Find the probability that the sum of the numbers on which the dice lands is 6 given that the red die lands on an

42. ## math

5.6 lb/gal = oz/gal

43. ## Chemistry

A mixture of ammonia and oxygen is prepared by combining 0.330 L of NH3 (measured at 0.790 atm and 22°C) with 0.210 L of O2 (measured at 0.820 atm and 48°C). How many milliliters of N2 (measured at 0.740 atm and 100. °C) could be formed if the following

44. ## Chemistry

18) Aspirin is a monoprotic acid called acetylsalicylic acid. Its formula is HC9H7O4. A certain pain reliever was analyzed for aspirin by dissolving 0.534 g of it in water and titrating it with 0.0446 M KOH solution. The titration required 26.73 mL of

45. ## Chemistry

12) Naturally occurring argon is composed of 0.3365% of 36Ar (atomic mass, 35.9675 u), 0.0632% of 38Ar (atomic mass, 37.9627 u), and 99.6003% of 40Ar (atomic mass, 39.9624 u). Use these data to calculate the average atomic mass of argon.

46. ## Chemistry

How many grams of water could have its temperature raised from 25 ºC (room temperature) to 100 ºC (the boiling point of water) by the amount of energy released in the formation of 4.0 mol of H2 from hydrogen atoms? The bond energy of H2 is 435 kJ/mol.

47. ## Chemistry

In the spectrum of a specific element, there is a line with a wavelength of 656 nm. Use the Rydberg equation to calculate the value of n for the higher energy Bohr orbit involved in the emission of this light. Assume the value for the lower energy orbit

48. ## Chemistry

Microwaves are used to heat food in microwave ovens. The microwave radiation is absorbed by moisture in the food. This heats the water, and as the water becomes hot, so does the food. How many photons having a wavelength of 3.00 mm would have to be

49. ## Chemistry

When 4.76 g of a solid mixture composed of NH4Cl and CaCl2 was dissolved in 100.0 mL of water, the temperature of the water rose by 4.73°C. How many grams of each substance was in the mixture?

50. ## english

Need Help Please..!!! During the Victorian period, there were many social changes and intellectual developments. As a result, a crisis of faith rocked society. How does In Memoriam, A. H. H. by Alfred, Lord Tennyson reflect that crisis? a)Grieving, the

51. ## Math

Why did Karjam Get a flat tire.

52. ## statistics

All deal with a random variable X that follows a normal probability distribution with mean equal to 37 and a standard deviation of 5. Compute P(X < 39) Compute P(X < 29 or X > 41) Compute P(X > 30) Find the 42nd percentile for this distribution.

53. ## Physics

While following the directions on a treasure map, a pirate walks 36.6 m north, then turns and walks 6.3 m east. A.) What is the magnitude of the single straight-line displacement that the pirate could have taken to reach the treasure? Answer in units of m.

54. ## chem

Which statement is wrong? 1. Adding the same amount of heat to two different objects will produce the same increase in temperature. 2. When the same amount of heat produces different changes in temperature in two substances of the same mass, we say that

55. ## chem

How many molecules are in 1.60 g of SO2? Answer in units of molec

56. ## chemistry

What happens to the concentration of SO2(g) when the total pressure on the equilibrium reaction 2 SO2(g) + O2(g) 2 SO3(g) is increased (by compression)? I thought it remained the same but that was incorrect.

57. ## Physics

suppose that the charge on the electron and proton did not have the same magnitude but instead differed by one part in 10^10. What would be the net charge on a 1.0 kg sample of helium gas?

58. ## Algebra II

If x Ω y is defined as the smallest integer of which both x and y are factors, then 10 Ω 32 is how much greater than 6 Ω 20? A. 2 B. 70 C. 100 D. 160 E. 200

59. ## physics

please help i cannot figure this out A 0.27 kg ball of dough is thrown straight up into the air with an initial velocity of 12 m/s. Find the momentum of the ball of dough halfway to its maximum height on the way up. and A 61 kg pole-vaulter falls from rest

60. ## finite mathmatics

elimination method 5x + 6y = -75x - 3y = 146

61. ## physics

Please help! I am so stuck on the force diagrams A uniform metal rod of mass 100 kg and L (2.5m) is suspended from the side of the building. On the far end of a mass of 100 kg is hung by a rope, (distance L from a building). The rod is connected to the

62. ## physics

A spy in a speed boat is being chased down a river by government officials in a faster craft. just as the officials' boat pulls up next to the spy's boat both boats reach the edge of a 5.0meter waterfall. If the spies speed is 15m/s and the officials'

How do find the speed of a marble after falling from rest a distance of 1.2 m?

65. ## PHYSICS

A potential energy function for a two-dimensional force is of the form U = 2.46x3 y - 5.05x (which has units of J). Calculate the force that acts at the point (1.26 m,1.18 m).

66. ## PHYSICS

A luggage carousel at an airport has the form of a section of a large cone, steadily rotating about its vertical axis. Its metallic surface slopes downward toward the outside, making an angle of 23.0 degrees with the horizontal. A piece of luggage having

67. ## chemistry

a metal sample weighing 45.0g and at a temperature of 99.1C was place in 38.6g of water in a calorimeter at 25.0C. the calorimeter reached a maximum temperature of 32.8C. 1. calculate the specific heat of the metal. 2. what is the approximate molar mass of

68. ## Brainteaser

A man is on his hands and knees looking for a £5 note he has dropped. His search for the fiver continues for some time. Finally in the corner of the room he finds it. What is the first thing he does? Anyone know this?????

69. ## Math

Hi how would i solve this?? The equation of the cirlce is x^2+y^2-4x+2y=0. Determine the coordinates of the center and the radius of the circle. What do i do? anyone

70. ## rational functions

A rational function that passes through (0,0) and (4, 8/7) has the x-axis as a horiztonal asympotote. It also has 2 vertical asymptotes x=3, x=-3. I understand that to set it up, it is y= ax+b / (x+3)(x-3). I don't understand how to solve for a and b.

71. ## chemistry

When 1.0 mol of ammonia gas in injected into a o.50L flask, the following reaction proceeds to equilibrium. 2NH3 N2 (g) + 3H2 (g) At equilibrium, 0.30 mol of hydrogen gas is present. a) calculate the equilibrium concentrations of N2 and Nh3. b) what is the

72. ## Math

The city zoo has different admission for adults and children. When three adults and two children went to the zoo, the bill was \$79.21. If two adults and three children got in for \$75.49, then what is the price of an adults ticket and what is the price of a

73. ## math

67 is the difference of Holly's age and 23.

74. ## science

Whats a funny acrostic joke for beryllium

75. ## Physics

A garden hose is used to fill a drum with water. The hose is held 0.88 m above the ground. The cross-sectional area of the 2.0 cm diameter hose is two times the cross-sectional area at the spout end where the water is coming out and the gage pressure

76. ## chemistry

Suppose that the microwave radiation has a wavelength of 12 cm . How many photons are required to heat 295 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

77. ## Java

If I declare a method static, does it mean only a class can call that method?

78. ## Government

I have to connect littering to a specific amendment in the Bill of Rights. I have read all of them. Could someone help? I’m stuck.

79. ## Math

The measure of angle a is 124° what is the correct classification for angle a is it Acute right obtuse straight

80. ## Art

Choose the pairing that is an example of archival materials a acid-free paper superglue be salt construction paper for the glass case superglue the acid free paper glass case I think it is D

81. ## Art

Choose the pairing that is an example of archival materials a acid free paper such as superglue basalt construction paper salt glass case superglue Acid free paper glass case I say b

82. ## Physics

friction force does -200 J of work on a baseball player of mass 45.0 kg when she has stopped after sliding into second base. what was her initial velocity?

83. ## Physics

It takes earth 365 days to complete one orbit around the sun. Knowing that the magnitude of the average acceleration of the earth experiences is over half an orbit is 3.78 x 10^-3 m/s^2, what is the average speed with which it travels?

84. ## Algebra

Sorry if this is a silly question, but can anyone algebraically explain to me how these two equations are equivalent. 360/(180-x)=y (-360+180y)/x=y Desmos shows that they're the same line: attps://www.desmos.com/calculator/7nkhupilpc and replace a with h

85. ## English

Give a brief summary of Home Place by guy vanderhaeghe.

86. ## Calculus

Use geometry to evaluate integral[-3,3] for: f(x)= { √(4-(x+1)^2), -3≤x≤1 { |x-2| - 1, 1

87. ## Maths

A bus travels at 70km/h for x hours and then at 80km/h for 0.5(x+3) hours. the total distance travelled was 460km. Determine x correct to the nearset minute.

88. ## math

A bus travels 70km/h for xhours and then at 80km/h for (0.5x+3) hours. If the total distance traveled is 460km, find x to the nearest minute.

89. ## electrical

use diagram and text to explain how junction diode is able to conduct an electric current in one direction. use each of the following terms. -semiconductor -crystal -hole -N type -depletion region -potential difference -P type -electron -attraction

90. ## Chemistry

Use the ion-electron method to write and balance the net ionic equation for each of the following reactions. MnO41- + Sn(OH)31- MnO2 + Sn(OH)62- in basic solution MnO41- + (COOH)2(aq) Mn2+ + CO2(g) in acidic solution I2(aq) + S2O32- I1- + S4O62- Zn(s) +

91. ## Urgent math question help!!!

Drag and drop the correct justifications into the boxes. 4(x−2)+1=9 : subtraction property of equality 4x−8+1=9 :combine like terms 4x−7=9 : distributive property 4x = 16 : associative property of equality x = 4 : division property of equality

92. ## Chemistry Help

The most effective buffer solutions have equal concentrations of salt and acid (or base). Find the pH of a buffer solution with equimolar concentrations of: (a) HCOOH and NaCOOH (Ka = 3.5 x 10-4 for HCOOH) (b)CH3NH2 and CH3NH3Cl (Kb = 3.7 x 10-4 for

93. ## math

A concert arena has 48 rows, each with 8 seats and another 54 rows, each with 9 seats. How many seats does the concert arena have?

94. ## Calculus

A chemical substance is draining from a conical filtering system at a rate of 100 cubic centimeters per minute into a cylindrical storage tank below. The conical filter and cylindrical tank each have a diameter of 60 centimeters, and the height of the cone

95. ## Trig identities

Has a negative -5/13 Steve. If angles x and y are in the same quadrant and sin x =3/5 and cos y= -5/13 determine the value of sin (x-y)

96. ## Trigonometric identities

If angle x and y are in the same quadrant , and sin x=3/5 and cos y=5/13, determine the value of sin(x-y) .

97. ## science

A solution of aqueous ammonia contains 28.0% NH3 by mass. the solution has a density of 0.898g/mL. calculate the volume of this solution required to make 425mLof 0.320M NH3 solution.

98. ## math

Which expression shows 27 + 36 as the product of their greatest common factor and the sum of two whole numbers with no common factor? ​ 7(4+5)7(4+5) ​ ​ 9(4+5)9(4+5) ​ ​ 9(3+4)9(3+4) ​ ​ 7(3+6)7(3+6) ​

99. ## Haematology

Define terms: - clinical conditions - pathological conditions - physiological conditions These terms have me confused..