# Luke

Popular questions and responses by Luke-
## 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

*asked on June 29, 2014* -
## math

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

*asked on August 18, 2010* -
## 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?

*asked on May 27, 2018* -
## 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

*asked on June 7, 2015* -
## 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.

*asked on February 2, 2018* -
## 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

*asked on February 4, 2019* -
## 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

*asked on March 6, 2013* -
## Maths

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

*asked on February 17, 2017* -
## math

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

*asked on December 9, 2013* -
## Chem

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

*asked on June 26, 2014* -
## 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.

*asked on December 8, 2013* -
## 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.

*asked on February 16, 2013* -
## 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.

*asked on May 25, 2018* -
## 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

*asked on February 27, 2014* -
## Super Easy Math Question

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

*asked on October 19, 2011* -
## Geometry

How do you divide a hexagon into 9 congruent parts?

*asked on October 3, 2007* -
## science

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

*asked on February 24, 2020* -
## 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

*asked on November 8, 2015* -
## 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) ->

*asked on July 8, 2014* -
## Calculus

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

*asked on October 21, 2011* -
## 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.

*asked on October 10, 2011* -
## 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?

*asked on February 12, 2009* -
## math

how does a rodeo star get around?

*asked on March 2, 2016* -
## 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?

*asked on July 14, 2014* -
## 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

*asked on April 26, 2013* -
## 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 :)

*asked on May 24, 2016* -
## 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.)

*asked on March 10, 2016* -
## science

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

*asked on September 24, 2015* -
## 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?

*asked on April 3, 2012* -
## 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?

*asked on December 8, 2011* -
## 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.

*asked on October 25, 2011* -
## 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?

*asked on October 2, 2011* -
## 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

*asked on December 5, 2008* -
## Math

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

*asked on February 21, 2020* -
## 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

*asked on June 9, 2019* -
## 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

*asked on May 28, 2018* -
## 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?

*asked on May 27, 2018* -
## 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

*asked on May 26, 2018* -
## 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

*asked on December 13, 2016* -
## 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.

*asked on March 9, 2016* -
## 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

*asked on February 14, 2016* -
## math

5.6 lb/gal = oz/gal

*asked on December 13, 2014* -
## 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

*asked on July 8, 2014* -
## 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

*asked on July 1, 2014* -
## 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.

*asked on July 1, 2014* -
## 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.

*asked on June 29, 2014* -
## 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

*asked on June 29, 2014* -
## 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

*asked on June 29, 2014* -
## 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?

*asked on June 26, 2014* -
## 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

*asked on October 31, 2013* -
## Math

Why did Karjam Get a flat tire.

*asked on October 9, 2013* -
## 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.

*asked on April 25, 2013* -
## 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.

*asked on November 8, 2012* -
## 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

*asked on April 25, 2012* -
## chem

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

*asked on April 19, 2012* -
## 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.

*asked on April 3, 2012* -
## 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?

*asked on February 22, 2012* -
## 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

*asked on July 26, 2011* -
## 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

*asked on March 21, 2011* -
## finite mathmatics

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

*asked on December 11, 2010* -
## 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

*asked on November 26, 2010* -
## 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'

*asked on November 6, 2010* -
## 10th grade

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

*asked on October 21, 2010* -
## maths

exact value for tan(7pi/6 radians)

*asked on March 23, 2010* -
## 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).

*asked on September 29, 2009* -
## 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

*asked on September 21, 2009* -
## 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

*asked on November 13, 2008* -
## 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?????

*asked on April 16, 2008* -
## 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

*asked on May 31, 2007* -
## 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.

*asked on January 27, 2007* -
## 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

*asked on November 26, 2006* -
## 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

*asked on April 20, 2020* -
## math

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

*asked on January 24, 2020* -
## science

Whats a funny acrostic joke for beryllium

*asked on September 27, 2019* -
## 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

*asked on July 3, 2019* -
## 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

*asked on June 9, 2019* -
## Java

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

*asked on May 5, 2019* -
## 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.

*asked on May 4, 2019* -
## Math

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

*asked on February 4, 2019* -
## 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

*asked on February 1, 2019* -
## 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

*asked on February 1, 2019* -
## 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?

*asked on October 24, 2018* -
## 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?

*asked on October 15, 2018* -
## 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

*asked on October 9, 2018* -
## English

Give a brief summary of Home Place by guy vanderhaeghe.

*asked on September 18, 2018* -
## Calculus

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

*asked on May 17, 2018* -
## 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.

*asked on June 12, 2017* -
## 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.

*asked on June 9, 2017* -
## 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

*asked on April 27, 2017* -
## 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) +

*asked on March 21, 2017* -
## 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

*asked on March 2, 2017* -
## 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

*asked on February 23, 2017* -
## 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?

*asked on January 9, 2017* -
## 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

*asked on December 19, 2016* -
## 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)

*asked on December 8, 2016* -
## 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) .

*asked on December 8, 2016* -
## 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.

*asked on November 18, 2016* -
## 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)

*asked on October 11, 2016* -
## Haematology

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

*asked on October 8, 2016* -
## Chemistry

A 2.80-g sample of haematite ore containing Fe3+ ions was dissolved in a concentrated acid and the solution was diluted to 250 mL. A 25.0 mL aliquot was reduced with Sn2+ to form a solution of Fe2+ ions. This solution of Fe2+ ions required26.4mL of a

*asked on August 23, 2016*