# Lauren

Popular questions and responses by Lauren
1. ## Chemistry

a diver exhales a bubble with a volume of 250 mL at a pressure of 2.4 atm and a temperature of 15 degrees celcius. What is the volume of the bubble when it reaches the surface where the pressure is 1.0 atm and the temperature is 27 degrees celcius

2. ## chemistry

You are a workstudy for the chemistry department. Your supervisor has just asked you to prepare 500mL of 3M HCl for tomorrow's undergraduate experiment. In the stockroom explorer, you will find a cabinet called "Stock Solutions". Open this cabinet to find

3. ## Chemistry

N2(g) + 3H2(g)  2NH3(g) at STP How many litres of ammonia gas is produced using 5 litres of H2? N2 + 3H2 ---> 2NH3 - the ratio between H2 and NH3 is 3 : 2 - it's given 5 litres of H2, so the volume of NH3 formed is 5/3*2 = 10/3 = 3.33 (L) Sig FIG ANSWER

4. ## Chemistry

Convert 25 mL of 0.80 mol/L Mg(NO3)2(aq) into moles moles of Mg(NO3)2 = 0.8 x (25/1000) = 0.02

5. ## Chemistry

2 C8H18(g) + 25 O2(g)  16 CO2(g) + 18 H2O­(g) at STP How many moles of O2 are needed to react with 60.0g of C8H18 (octane)? mole of 02 = 60/114 = 53 mols 2 moles of octane =25 mols of 02 0.53/2 x 25= 6.625 answer is 6.6 mols How many litres of CO2 are

6. ## Chemistry

Zn(s) + 2HCl(l)  ZnCl2(s) + H2(g) at STP What mass of zinc is needed to produce 115 mL of hydrogen? - it's given 115 mL of hydrogen, so can convert to 115/1000/22,4 = 0.0051 moles H2 - the ratio between HCl and H2 is 2 : 1, so the moles of HCl needed

7. ## Chemistry

Complete this Bronsted-Lowry reaction, placing each product by it's appropriate label. HSO4- + BrO- ____ (ACID) + ____ (BASE)

8. ## Chemistry

Consider an ideal gas encloesd in a 1.00 L container at an internal pressure of 10.0 atm. Calculate the work, w, if the gas expands against a constant external pressure of 1.00 atm to a final volume of 20.0 L. w = ____ J now calculate the work done if this

9. ## chemistry

2 KOH(l) + H3PO4(l) --> K2HPO4(l) + 2 H2O(l) a) How many mL of 0.450M KOH is needed to react with 60.0mL of 0.250M H3PO4? a) 0.060L x 0.250M = 0.015 mol H3PO4 0.015mol H3PO4 x 2mol KOH / 1mol H3PO4 = 0.03 mol KOH 0.03 mol KOH x 1L/0.450 mol = 0.06667L =

10. ## Chemistry

Complete the table by filling in the formula for the ionic compound formed by each pair of cations and anions, as shown for the first pair. Ion K+ NH+4 Mg2+ Fe3+ Cl- OH- CO3 2- PO3- 4 Complete the fourth row of the table.

11. ## Math

A cone-shaped pile of sawdust has a base diameter of 40 feet, and is 15 feet tall. Find the volume of the sawdust pile. Round your answer to the nearest hundredth if necessary. Use 3.14

12. ## Chemistry

a precipitate is expected when an aqueous solution of potassium iodide is added to an aqueous solution of: sodium sulfate iron(II) chloride calcium perchlorate barium hydroxide lead nitrate

13. ## spanish

what would the possesive pronoun be? Se me quedaron en casa los libros. ¿Trajo Ana ____ (hers)? Uso mi teléfono celular cuando viajo. ¿Cuándo usa Ramón _____ (his)? Tu profesora es muy simpática. _____ (Ours) es simpática también. Me encantan mis

14. ## mathematiks concepts

A must when introducing each whole number operation is to A. encourage the students to work fast. B. make liberal use of real-life story problems that the students can act out. C. begin with flash card games. D. be sure all students are on the same page in

15. ## Texas State History

What is the purpose of the NAFTA treaty?

16. ## chemistry

Fe2+(aq) + Cr2O7 2- (aq) →Fe3+(aq) + Cr3+(aq) Balance the equation by using oxidation and reduction half reactions. What is smallest possible integer coeﬃcient of Cr3+ in the combined balanced equation?

17. ## Chemistry

Decide which of the following bonds is least polar on the basis of electronegativities of atoms, H---S, Si---Cl, N---Cl.

18. ## statistics

The number of column inches of classified advertisements appearing on Mondays in a certain daily newspaper has mean 320 inches and standard deviation 30 inches. Suppose that the results for 100 consecutive Mondays can be regarded as a random sample and let

19. ## Physics

A model electric train requires 6 V to operate. If the primary coil of its transformer has 240 windings, how many windings should the secondary have if the primary is connected to a 120 V household circuit?

20. ## English

Which of the following is a good rule to follow when proofreading an essay? A. Scan the essay twice, once for organization and once for surface errors. B. Ask your best friend to critique your essay. C. Use the computer's spell-check and grammar-check

21. ## physics

Unpolarized light passes through six successive Polaroid sheets each of whose axis makes a 59 degree angle with the previous one. What is the intensity of the transmitted beam, I/Io?

22. ## Physics

A +3.0 nC charge is at x=0 cm and a -1.0 nC charge is at x=4 cm. At what point or points on the x-axis is the electric potential zero?

23. ## college math

a bag contains 7 red chips and 9 blue chips. Two chips are selected randomly from the bag without replacement. What is the probability that the two chips are the same color? If someone could just point me in the right direction for the many equations I

24. ## Geometry

Quadrilateral ABCD is a parallelogram. If adjacent angles are congruent, which statement must be true? A. Quadrilateral ABCD is a square. B. Quadrilateral ABCD is a rhombus. C. Quadrilateral ABCD is a rectangle. D. Quadrilateral ABCD is an isosceles

25. ## Chemistry

Predict the order of increasing vapor pressure at a given temperature for the following compounds: CH3CH2CH2CH2OH HOCH2CH2CH2OH CH3CH2OCH2CH3

26. ## College Algebra

Cassius drives his boat upstream for 30 minutes. It takes him 15 minutes to return downstream. His speed going upstream is two miles per hour slower than his speed going down stream. Find his upstream and downstream speed.

27. ## Chemisty

Aluminum hydroxide forms a positively charged sol. Which of the following ionic substances should be most effective in coagulating the sol? NaCl CaCl2 Fe2(SO4)3 K3PO4 The idea behind coagulating sols is to use those salts that have the highest + and -

Three masses are connected by a string. M1 = 1.0kg M2 = 2.0kg M3 = 3.0kg Mass one and two are on a table while mass three hangs off the edge of the table (there is a pulley). Find the tension in the string connecting m1 and m2. Assume the table is

29. ## geometry

if a polyhedron has a volume of 14 cm and is dilated by a factor of 1/5, what will be the volume of the dilated polyhedron? ROund your answer to the nearest thousandth if necessary

30. ## chemistry

Solid zinc and aqueous hydrogen sulfate reacts to produce hydrogen gas and aqueous zinc sulfate Is this the right answer Z(aq)+HS equals H(G) ZS? if not can u please correct me

31. ## Chemistry

Classify each of the following by the type of solid if forms: a. LiCl b. BaCl2 c. BCl3 d. CCl4 e. NCl3 I have four different types of solids to guess from like Metallic solid, ionic solid, molecular solid, covalent network solid and i don't know which goes

32. ## Chemistry

The freezing point of ethanol is -114.6 C and its Kf value is 2.00 C/m. What is the freezing point for the solution prepared by dissolving 50.0 g of glycerin (C3H8O3) in 200.0 g ethanol? I used Change in temp=Kfm kf=2.00 I calculated m to be 2.1736. I

33. ## chemistry

a tank contains helium gas at 490 mmHg, nitrogen gas at 0.75 atm, and neon at 520 torr. What is the total pressure in atm?

34. ## algebra

Sarah blends coffee for Tasti-Delight. She needs to prepare 170 lbs of blended coffee beans selling for \$3.59 per pound. She plans to do this by blending together a high-quality bean costing \$5.00 per pound and a cheaper bean at \$2.00 per pound. To the

35. ## Physics w/ Calc

A baseball approaches home plate at a speed of 43.0 m/s, moving horizontally just before being hit by a bat. The batter hits a pop-up such that after hitting the bat, the baseball is moving at 54.0 m/s straight up. The ball has a mass of 145 g and is in

36. ## Physics

At time t = 0s, a puck is sliding on a horizontal table with a velocity 3.00 m/s, 65.0 above the +x axis. As the puck slides, a constant acceleration acts on it that was the following components: ax = 0.460m/s2 and ay = 0.980m/s2. what is the velocity of

37. ## Chemistry

According to your calculations a reaction should yield 5.67 g of oxygen O2. What do you expect the volume to be at 23 degrees C and 0.985 atm? I got the all the amounts 5.67 g 23 degrees C = 296 K .985 atm And use the ideal gas law Can you help me out by

38. ## Trig

Find the exact circular function value for: sec(23pi/6) I know the answer should be: [2sqrt(3)]/3, but I do not understand how to solve the problem. I have a unit circle, but 23pi/6 is not on it, so I don't know how to find the (x,y)

39. ## Chemistry

All of the following are weak acids except HF H3PO4 H2SO4 HNO2 HC2H3O2

40. ## Science

Helium gas in a balloon occupies 2.5 L at 300.0 K. The balloon is dipped into liquid nitrogen that is at a temperature of 80.0 k. What will the volume of the helium in the balloon at the lower temperature be? I got a weird answer like .66667 and i used

41. ## PROB

Researchers at the University of Pennsylvania School of Medicine have determined that children under 2 years old who sleep with the lights on have a 36% chance of becoming myopic before they turn 16. Children who sleep in darkness have a 21% chance of

42. ## Chemistry

Caffeine C8H10N4O2, is a stimulant found in a tea and coffee. A sample of the substance was dissolved in 45.0g of choloroform CHCl3 to give a 0.0946m solution. How many grams of caffine were in the sample. m = molality

43. ## Chemistry

A quantity of ice at 0.0 degrees C was added to 33.6 of water at 21.0 degree C to give water at 0.0 degrees C. How much ice was added? The heat of fusion of water is 6.01 kJ/mol and the specific heat is 4.18 J/(g * degrees C) q = mass x specific heat x

44. ## Chemistry

What is the wavelength of the transition from n=4 to n=3 for Li2+? In what region of the spectrum does this emission occur? Li2+ is a hydrogen-like ion. Such an ion has a nucleus of charge +Ze and a single electron outside this nucleus. The energy levels

45. ## CHEM

Can you please check my work? I got -4.3KJ/mol If this is not right can you tell me what I am doing wrong? Thank you! Questions. 1.a. Use Hess's Law and the measured mean enthalpy changes for the NaOH-HCl and NH3-HCl reactions to calculate the enthalpy

46. ## Chemistry

Aspirin is prepared by heating salicylic acid, C7H6O3, with acetic anhydride, C4H603. The other product produced is acetic acid, C2H402. C7H6O3+C4H6)3->C9H8O4+C2H4O2 What is the theoretical yield in grams of aspirin, C9H8O4, when 2.00 grams of salicylic

47. ## Chemistry

A 0.1873 g sample of a pure, solid acid, H2X was dissolved in water and titrated with 0.1052 M NaOH solution. The balanced equation for the neutralization reaction occurring is H2X(aq) + 2NaOH(aq) ¨ Na2X(aq) + 2H2O(l) If the molar mass of H2X is 85.00

48. ## statistics

an airline estimates that 97%of people booked on their flights actually show up.if the airline books 70 people on a flight for which the maximum number is 68,what is the probability that the number of people who show up will exceed the capacity of theplane

49. ## Geometry

1. Let S be between R and T. Use the Segment Addition Postulate to solve for m. RS = 2m + 2 ST = 3m + 3 RT = 15 A. m = 3 B. m = 2 C. m = 9 D. m = 4

50. ## math

one estimate for the ideal body weight of a woman is shown below. use this information to answer part (a) through (d) 55kg+1.5kg for each inch over 5 feet (a) find a linear model for an estimate of the ideal weight of a woman using W for ideal body weight

51. ## Financial Accouting

Prepare a 10-column work sheet for fiscal year 2005, starting with the unadjusted trial balance and including adjustments based on these additional facts: a. The supplies available at the end of fiscal year 2005 had a cost of \$3,200. b. The cost of expired

52. ## Physics

The hypotenuse of a right triangle is 29.0 centimeters. The length of one of its legs is 20.0 centimeters. What is the length of the other leg?

53. ## science

The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water: 2C2H2 (g) + 5O2 (g) ¨ 4CO2 (g) + 2H2O (l) The value of ƒ¢So for this reaction is __________ J/K.

54. ## Science!

CuCO3 + O2 -> CuO + CO2 hydrogen peroxide + manganese dioxide -> hydrogen + oxygen copper (II) sulfate pentahydrate + oxygen -> copper oxide + sulfur trioxide + dihydrogen monoxide What are the balanced queations for these?

55. ## chemistry

Ca(NO 3 ) 2 + Na 2 CO 3 �� CaCO 3 + 2NaNO 3 net ionic equation?

56. ## English

1 When he awoke, it was three o’clock in the afternoon. He bounded up with a start; half of one of 2 his precious days gone already! He spent more than an hour in dressing, watching every stage of his 3 toilet carefully in the mirror. Everything was

57. ## Physics

A body of mass m falls from rest through the air. A drag force D = bv^2 opposes the the motion of the body. The acceleration due to gravity is g. A) What is the initial downward acceleration of the body? B) After some time the speed of the body approaches

58. ## physics

our charges are placed at the four corners of a square of side 15 cm. The charges on the upper left and right corners are +3 μC and -6 μC respectively. The charges on the lower left and right corners are -2.4 μC and -9 μC respectively. The net electric

59. ## Organic Chemistry

Draw every stereoisomer for 1-bromo-2-chloro-1,2-difluorocyclopentane. Use wedge-and-dash bonds for the substituent groups, and be sure that they are drawn on the outside of the ring, adjacent to each other.

60. ## chemistry

Complete and balance the precipitation reactions. Include physical states in your equations. Ba(NO3)2(aq) + CuSO4 (aq)---> K3PO4(aq)+MgCl2 (aq)---->

61. ## Algebra 1

Let x be an integer. What is the product of twice the integer added to three times the next consecutive integer?

62. ## Math analysis

How do I simplify cscx-cotxcosx?

63. ## Physics

An electron enters a parallel plate apparatus 10.0cm long and 2.0cm wide, moving horizontally at 8.0 × 10^7 m/s. (top plate is positive, electron is 1.0cm from each plate..) The potential difference between the plates is 6.0 × 10^2 V. Calculate... (a)

64. ## Chem

Give the ideal bond angle for BrO3- ion? I know this has trigonal bipyramidal geometry and therefore the bond angle is < 109.5. Is there a way to determine a more specific bond angle?

65. ## math

a rectangular box with a volume of 60 ft^3 fas a square base. Find a funtion that models its surface area S in terms of the length x of one side of its base

66. ## Chemisty

What is the molecularity of each of the following elementary reactions? A. O+O2+N2----> O3+N2+ B. NO2Cl + Cl---> NO2 + Cl2 C. Cl + H2 ---> HCl + H D. CS2----> CS + S

67. ## Chemistry

Concentrated aqueous ammonia contains 1.00 mol NH3 dissolved in 2.44 mol H20. What is the mole fraction of NH3 in concentrated aqueous ammonia? What is the molal concentration of NH3

68. ## Chemistry

Liquid Butane, C4H10, is stored in cylinders to be used as a fuel. Suppose 39.3g of butane gas is removed from a cylinder. How much heat must be provided to vaporize this much gas? The heat of vaporization of butane is 21.3 kJ/mol.

69. ## Chemistry

When 23.6 of calcium chloirde CaCl2 was dissolved in water in a calorimeter, the temperature rose from 25.0 degrees C to 21.56 degrees C. If the heat capacity of the solution and the calorimeter is 1071 J/ degrees C, what is the enthalpy change when 1 mol

70. ## sci

Suppose you are in charge of planning a forest reserve, and one of your main goals is to help sustain locally beleaguered populations of woodland birds. Parasitism by the brown-headed cowbird is an escalating problem in the area. Reading research reports,

71. ## Chemistry

Write the net ionic equation for the following reaction : Na3SO4(aq) + Ba(NO3)2(aq) —> BaSO4 (s) + 2 NaNO3(aq)

72. ## math

Name the congruent angles and sides for the pair of congruent triangles. ∆MGB ≅ ∆WYT

73. ## algebra

a water rocket is launched with an initial velocity of 112ft/sec. its height h, in feet T seconds is given by the formula h=112T-16T^2. when will the rocket be exactly 192 ft above the ground? the rocket first reaches a height of 192ft after _____ and

74. ## chemistry

Gaseous butane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 29.1 g of butane is mixed with 64. g of oxygen. Calculate the minimum mass of butane that could be left over by the chemical reaction. Be sure your

75. ## pe 8

1. Which side of the health triangle corresponds to getting enough rest? a) physical health b) social health c) mental and emotional health*** d) none of the above Am I right?

76. ## Math

There are two integers from 1 through 40 and are chosen by a random number generator. Write the final answer in a/b form. 1.) P(the same number is chosen twice) 2.) P(both numbers are less than 30) 3.) P(one number is even and one number is odd) 4.) P(both

77. ## English

Which sentence should be edited to eliminate its cliché? A. The texture of the burlap was a cross between woven straw and a three-day beard. B. The family was immensely relieved when Great-Aunt Martha's condition progressed from "critical" to "it looks

78. ## physics

A light, inextensible cord passes over a light, frictionless pulley with a radius of 11 cm. It has a(n) 14 kg mass on the left and a(n) 4.3 kg mass on the right, both hanging freely. Initially their center of masses are a vertical distance 2.1 m apart. The

79. ## geometry

What is the altitude of a rhombus if its area is 50 square meters and the length on one side is 12.5 meters? A. 10 m B. 4 m C. 7.5 m D. 12.5 m

80. ## Physics

if pressure inside a cylinder with a circular hatch is 2 atm and the radius of the entrance hatch is 12 inches, what force does the air exert on the hatch? i cannot figure out if it would be 13,300.6 lb 24 lb 288 lb 1,300.6 lb or 904.8 lb

81. ## Physics

A spring whose spring constant is 650 N/m is compressed 0.600 m. What speed (in meters/second) can it give to a 0.100 kg ball when released

82. ## Calculus

an open top box is to be made by cutting congruent squares of side length x from the corners of a 12 by 15 inch sheet of tin and bending up the sides. how large should the squares be? what is the resulting maximum value?

83. ## Physics

Three blocks rest on a frictionless, horizontal table (see figure below), with m1 = 8 kg and m3 = 20 kg. A horizontal force F = 101 N is applied to block 1, and the acceleration of all three blocks is found to be 3.5 m/s2. Find m2. What is the normal force

84. ## Trigonometry

How do I find the value of sin(a-b) if tana=4/3, cotb=5/12, 0

85. ## Chemistry

how do you write a chemical equation with this reaction? can u help me solve these 1.Liquid carbon disulfide reacts with oxygen gas, producing carbon dioxide gas and sulfur dioxdie gas. 2. Solid zinc and aqueous hydrogen sulfate reacts to produce hydrogen

86. ## Chemistry

NaCl crystallizes in face-centered cubic cell. what is the total number of ions(Na+ ions and Cr- ions) that lie withing a unit cell of NaCl? 2 4 8 6 5

87. ## Chemistry

which of the following compounds would you expect to exhibit only London forces? CCL4 CCLH CaI2 PCl5

88. ## Chemistry

The principal quantum number of the valence electrons in a atom of lead is A. 2 B. 3 C. 4 D. 5 E. 6

89. ## Chem

Calculate the frequency associated with light of wavelength 656nm. (this corresponds to one of the wavelengths of light emitted by the hydrogen atom.)

90. ## Chemistry

A 2.50 L flask was used to collect a 5.65 g sample of propane gas, C3H8. After the sample was collected, the gas pressure was found to be 741 mmHg. What was the temperature of the propane in the flask. P= 741 mmHg(1 atm/760 mmHg)= .975 atm V= 2.50 L n=

91. ## Chemistry

2. Complete the conversions below. Please show your work and include units in your final answer i. 8.5m = ? mm ii. 1.236km = ?cm iii. 400mL = ?L iv. 25.25cm = ? Tm v. 1zm = ? Zm vi. 45.6mol = ? mmol vii. 8,000,000km = ? nm viii. 1000cm3 = ? L ix. 25m3 = ?

92. ## writing

Assume that a new employee is taking over your job because you have been promoted. Identify a specific problem in the job that could cause difficulty for the new employee. Assume that you will need to write instructions for the employee to help him or her

93. ## English

The following is an example of regional dialect from which author? "The feller took the money and started away; and when he was going out at the door, he sorter jerked his thumb over his shoulder­­so­­at Dan'l, and says again, very deliberate, 'Well,'

94. ## Chemistry

Acid-Base Titrations These are fill in the blank and I really am not sure what the answers are 1. Indicators change color over a range that is called its ---? 2. The common indicator ---? is very useful in studying neutralizations that involve strong acids

95. ## cultural diversity

Which is NOT a strategy that can be implemented by a teacher to understand a family’s goals for his or her child’s linguistic development? A. The teacher can create a parent survey. B. The teacher can assume each family has the same goal for their

96. ## English

Which of the following sentences contains an error in subject-verb agreement? A. Either Dennis or Susan is going to pick you up. B. Each of the 14 groups are going to contribute an item to the auction. C. Kristy, Molly, and Kate attend the same university

97. ## using skills

What is the primary advantage of purchasing a publisher's kit? A. The kits contain consumable supplies. B. Kits are self-contained and ready to use. C. Kits can be used as supplementary material. D. It provides opportunities for hands-on learning. my

98. ## math

Which statement is ALWAYS true? A) The sine of an angle is equal to the sine of the angle's complement. B) The cosine of an angle is equal to the sine of the angle's supplement. C) The sine of an angle is equal to the cosine of the angle's complement. D)