Newest questions and responses by Jen
  1. Chemistry

    The concentration of the stock solution will be approximately 7.50 x 10-5 M. How many milliliters of this stock solution is needed to prepare 50.0 mL of a 1.20 x 10-5 M solution? (Express your answer in the correct number of significant figures.

    asked on January 31, 2019
  2. Algebra

    Part 1: A rectangular garden has a walk around it of a width x. The garden is 20 ft by 15 ft. Write a function representing the combined area, A(x), of the garden walk. Write as a polynomial in standard form. Part 2: Use the function you came up with in

    asked on January 23, 2019
  3. History

    Zhou rulers claimed that they had won the Mandate of Heaven because they How did the zhou king control his vast kingdom What did zhou artisans discover

    asked on November 7, 2018
  4. Riddle

    I was once a noble beam, but now I’m battered and worn. However, I hold a secret message What Am I?

    asked on October 23, 2018
  5. geometry

    A rectangular water tank is supported above the ground by four pillars 5.0 m long whose diameters are 20 cm. If the tank were made 10 times longer, wider, and deeper, what diameter pillars would be needed? How much more water would the tank hold?

    asked on October 1, 2018
  6. geometry

    The total surface area of a rectangular solid is the sum of the areas of the six faces. If each dimension of a given rectangular solid is doubled, what effect does this have on the total surface area?

    asked on October 1, 2018
  7. Math

    Solve each system of linear equations. 1/ y=2x_3 y_2x=_3 Answer: 0=0 2/ 3x+y=4 _3x=y_7 Answer: 0=3 or 0=11 3/ y=_4x+1 4x=_y_6 answer: 0=5 or 0=7 4/ Y_x+3=0 X=y+3 answer: 0=0 Please,if the answers were wrong, helpe me for solve them

    asked on September 24, 2018
  8. Algebra

    Consider the monomials 15x^2, y^2 and 6x^3 a. Factor the monomials. b. What factors of these monomials are common factors? c. Find the greatest common factor of 15x^2, y^2 and 6x^3 I'm having a really hard time with this.

    asked on September 3, 2018
  9. chemistry

    in the preparation of the standard curve for protein analysis, 50mg BSA(bovine serum albumin) dissolved in water to a final volume of 5ml was used as stock solution.What is the weight of BSA in 0.1ml of stock solution? in 0.2ml?

    asked on August 26, 2018
  10. chemistry

    What weight of Ca(OH)2 is necessary to prepare 3,500ml of 0.7M of Ca(OH)2 solution?

    asked on August 26, 2018
  11. chemistry

    Using 0.1M phosphate buffer, pH 7.2, prepare 25ml each of the buffer solutions with the following concentrations at pH 7.2: 1. 0.005M 2. 0.05M 3. 0.010M

    asked on August 26, 2018
  12. chemistry

    In protein precipitation, two liters of 5mM buffer solution with pH 5.2 is needed in the isolation of albumin. Which among the buffer solutions is best fitted for the said purpose?justify your answer. a. acetate buffer with pka=4.73? b. tris-aminomethane

    asked on August 26, 2018
  13. chemistry

    which is a better cleansing agent, a 70% alcohol or a 40% alcohol?

    asked on June 7, 2018
  14. physics

    a convex lens of an optical instrument needs to form an inverted image that is 4 times smaller than the object. how far from the lens should the object be placed? Answer: behind the double focal point. can someone explain this to me please? i have a

    asked on April 28, 2018
  15. Chemistry

    The hybridization of nitrogen in FNO3 (or FONO2) I cannot for the life of me draw the spin diagram for the NO single bonds and NO double bonds. Sp2 hybridization?? I think? N is forming 3 sigma bonds and one Pi.

    asked on April 20, 2018
  16. chemistry

    an unknown alcohol reacts with sodium salt but further tests show the compound to be an aliphatic hydrocarbon. what structural unit is probably present in the hydrocarbon?

    asked on March 31, 2018
  17. chemistry

    theoretically, how much iodoform could be prepared from 25ml of 95% ethanol(sp. gr. 0.79)?

    asked on March 31, 2018
  18. chemistry

    why would acyl halides give higher yields of amides compared to carboxylic acids or esters on reaction with NH3?

    asked on March 30, 2018
  19. chemistry

    why should excess alkali be avoided in the ferric chloride test for acetic acid and benzoic acid?

    asked on March 30, 2018
  20. chemistry

    Why do alcohols that show little tendency to dissolve in water appear to dissolve readily in 85% phosphoric acid? Would you describe the latter behavior as solubility or a chemical reaction? Explain

    asked on March 24, 2018
  21. chemistry

    The aliphatic alcohols and ethers are isometric; seven structures may be written for the molecular formula, C4H10O. if you were required to identify an unknown of this formula, tell exactly how would you go about it.

    asked on March 24, 2018
  22. chemistry

    theoretically, how much iodoform could be prepared from 25ml of 95% of ethanol( 0.79)?

    asked on March 24, 2018
  23. chemistry

    an unknown alcohol reacts with sodium salt but further tests show the compound to be an aliphatic hydrocarbon. what structural unit is probably present in the hydrocarbon?

    asked on March 24, 2018
  24. science

    does 2-napthol soluble in sodium hydroxide? in water? in sodium bicarbonate?

    asked on March 24, 2018
  25. science

    does p-chlorophenol soluble in sodium bicarbonate?

    asked on March 24, 2018
  26. Statistics and Probability

    Let Y be the discrete random variable with probability function p(y) = (1/2)^(y+1) y = 0, 1, 2,... Find the moment-generating function m(t) for Y.

    asked on March 17, 2018
  27. Statistics and Probability

    Teams A and B play a series of games with the first team to win 4 games being declared the winner of the series. Suppose that team A independently wins each game with probability 0.6. Find the probability that team A wins the series.

    asked on March 17, 2018
  28. Science

    When water is mixed with another substance and the mixture will not scatter light, the mixture is a:? 1) suspension  2) compound  3) solution  4) substrate 

    asked on February 25, 2018
  29. math

    The cost cc (in dollars) for the fuel and maintenance of a go-cart is given by c=10x+900c=10x+900, where xx is the number of rides. It costs $25 per ride. How many rides does it take to break even?

    asked on February 2, 2018
  30. math

    A cockroach traveling 2 feet per second takes how long to scurry a distance of 46 feet? seconds

    asked on December 10, 2017
  31. physics

    A 751 kg block is pushed on the slope of a 30◦ frictionless inclined plane to give it an initial speed of 50 cm/s along the slope when the block is 1.3 m from the bottom of the incline. The acceleration of gravity is 9.8 m/s^2. What is the speed of the

    asked on December 7, 2017
  32. Algebra pleaseee helppp

    Canasta is played with two decks of 52 cards each plus the 4 jokers. A standard Canasta hand consists of 11 cards. How many hands are possible?

    asked on November 29, 2017
  33. Algebra

    In the 2011 Canada general election, 166 Conservatives, 103 NDPs, 34 Liberals, 4 Bloc Quebecois, and 1 Green were elected. If an all party committee is to be formed consisting of 9 Conservatives, 5 NDPs, 2 Liberals, 1 Bloc Quebecois and 1 Green, how many

    asked on November 28, 2017
  34. Algebra

    canasta is played with 2 decks of 52 cards each plus the 4 jokers. A standard canasta hand consists of 11 cards. How many hands are possible

    asked on November 27, 2017
  35. Algebra

    Write in sigma notation 1/3,2/9,-7/27,14/81,-23/243,34/729...

    asked on November 27, 2017
  36. Algebra

    Graph the solution set of the system of inequalities and give the exact coordinates of the intersection points of the related equations: y>x^2 -8 X+y≤1, The closest points I'm getting is (-2.5,-1.8) and (2.5,-1.5) but I feel like they're incorrect

    asked on November 24, 2017
  37. CAlculuss

    Solve the equations algebraivally, test the solution for validity, and graph the system to check your number of solutions. x^2-2y^2=2 xy=2

    asked on November 24, 2017
  38. CAlculuss

    Convert into standard form. Find any centres, vertices, foci, asymptotes, directices and axes of symmetry. 64x^2-36y^2-512x-216y=-124 I found the centre (4,-3), vertices (8.4,-3) , (-0.4,-3), foci (0.1,-4), (7.9,-3). I'm having a hard time finding the

    asked on November 24, 2017
  39. CAlculuss

    Find, in standard form, the equation of : the parabola with focus at (3,5) and directrix at x=-1

    asked on November 22, 2017
  40. texas historty

    what action did spain take to prevent the Mexican war of independence from spreading to texas

    asked on October 25, 2017
  41. texas historty

    what questions might steph Austin have asked himself before trying to solve a problem

    asked on October 25, 2017
  42. science

    Why are the oldest rocks on earth on continental crusts?

    asked on October 22, 2017
  43. Equality Studies

    What are some steps white Americans can take to check their privilege?

    asked on October 7, 2017
  44. Equality Studies

    Who are some prominent obese role models?

    asked on October 6, 2017
  45. algebra

    The cost of a long distance call is $0.31 for the 1st minute and $0.24 for each additional minute. How long can you talk without spending more than $5? (Write and solve an equation.)

    asked on September 30, 2017
  46. Algebra

    x > – 5 and x < 2 How would I graph this? the greater and less then signs are confusing me

    asked on September 30, 2017
  47. Algebra

    I can't recall how to simplify square roots and am stuck on the following problem: (-3a)x = √7x+3 x = -1/4 I am trying to solve for a (since this is part of a group of questions that feed of previous answers, I'm absolutely at a stand-still). Thanks in

    asked on September 26, 2017
  48. Math

    First student bought art, math and history books for $72. a+m+h=72 Second student bought art, chemistry and history books for $80. a+c+h=80 Third student bought chemistry, math and history books for $61. c+m+h=61 Fourth student bought art, math and

    asked on September 21, 2017
  49. Math


    asked on September 20, 2017
  50. Social studies

    5. What effect on the Columbian exchange does this image illustrate? (A). The population boom of domesticated animals that escaped into the wild. (B). The conversion of the physical environment.*** (C). The introduction of milk cows to the North Americans

    asked on September 13, 2017
  51. Social studies

    2. According to the map, how did people first arrive in North America? (A). They traveled by boat from Africa. (B). They sailed across the Atlantic ocean. (C). They migrated from South America to North America. (D). They walked or paddled from Asia to

    asked on September 13, 2017
  52. algebra

    Chris can be paid in one of two ways. Plan A is a salary of ​$380 per​ month, plus a commission of 9​% of sales. Plan B is a salary of ​$656 per​ month, plus a commission of 3​% of sales. For what amount of sales is Chris better off selecting

    asked on July 28, 2017
  53. math

    zeros are real number? true or false

    asked on June 22, 2017
  54. math

    the seat of real number is the union of the set of irrational number true or false?

    asked on June 22, 2017
  55. math

    a wire whose length is at most 114cm,is bent to form a rectangle.If the length of the rectangle is 5cm longer than the width, what is the maximum area of the rectangle?

    asked on June 14, 2017
  56. math

    the largest among three positive consecutive odd numbers is greater than the sum of -4 and the product of 3 and the smallest number. Determine the three numbers. z>-4+3 is the equation I have made but I do not know what to do next.pls. help me. thank you.

    asked on June 14, 2017
  57. Chemistry

    A saturated solution of NH4Cl was made using 500g of water at 90 degrees. the solution was cooled to 50 degrees. what mass of NH4Cl was crystallized

    asked on June 7, 2017
  58. Macroeconomics(PLEASE HELP)

    4. Techniques of Production Resource Resource Prices Land $4 Labor $2 Capital $5 Entrepreneurial Ability $3 Possible ProductionTechniques I II III IV 4 6 8 9 6 7 9 9 5 4 3 2 1 1 1 2 a. Which technique is the most efficient? b.  If the most efficient

    asked on May 5, 2017
  59. The End of the Cold War

    1. Which is the best example of how Reagan dealt with the Soviet Union from a position of strength? A. development of the strategic defence initiative B. U.s withdrawl of the salt II treaty from senate approval C. Reagan condemning martial law of Poland D

    asked on April 27, 2017
  60. Math

    1. x^9/X^2 x^11 X^7 7 X^5

    asked on April 24, 2017
  61. Chemistry

    I'm not sure how to do these and when I looked it up, maybe there was a diff. vocab used. Please help! 1.) How do you do atom/ion inventory of : Cu3(PO4)2 A. _____ formula units Cu3(PO4)2 B. _____ atoms Cu C. _____ atoms P D. _____ atoms O E. _____ ions

    asked on April 3, 2017
  62. English

    Would "“The chain that bound her here was of iron links..." be a hyperbole? If not, than what literacy device is this?

    asked on March 31, 2017
  63. Physics

    A billiard ball 0.62 kg moving at 8.2 m/a elastically strikes a bowling ball, 3.2 kg moving in opposite direction at 1.2 m/s Calculate final velocities The kinetic energy before the collision The kinetic energy after the collision

    asked on March 28, 2017

    Each year, 64 college basketball teams compete in the NCAA tournament . Sandbox . com recently offered a prize of $10 million to anyone who could correctly pick the winner in each of the tournament games. A. How many games are required to get one

    asked on March 26, 2017
  65. Math7/8


    asked on March 16, 2017
  66. Physics

    A ball is shot from the top of a building with an initial velocity of 20 m/s at an angle θ = 39° above the horizontal. If a nearby building is the same height and 55 m away, how far below the top of the building will the ball strike the nearby building?

    asked on February 26, 2017
  67. Finance

    Sheet Metals has an outstanding loan that calls for equal annual payments of $12,600.47 over the life of the loan. The original loan amount was $72,000 at an APR of 8.15 percent. How much of the third loan payment is interest? $5,868.00 $4,725.89 $4,896.48

    asked on February 5, 2017
  68. Finance

    You want to purchase a new condominium that costs $287,500. Your plan is to pay 25 percent down in cash and finance the balance over 15 years at 3.75 percent. What will be your monthly mortgage payment including principal and interest? $1,568.07 $1,333.33

    asked on February 5, 2017
  69. Algebra

    The arch of the bridge below is half an ellipse, a "semi-ellipse". The arch is 148m long and has a height of 48m at the center. The height of the arch is 10m at point p. What is the distance from p to the center?

    asked on January 25, 2017
  70. Math

    the area of a rectangle is given by the expression (x^3+7x^2+11x+2) in^2. The length of the rectangle is given by the expression (x+2) in. What is an expression for the width of the rectangle?

    asked on January 22, 2017
  71. Chemistry

    A.) Write a balanced chemical Eq'n for a reaction between MAGNESIUM & HYDROCHLORIC ACID. Answer: Magnesium + Hydrochloric Acid Mg (s) + 2 HCL (ag) ---- MgCl2 (aq) H2(g) B.) Assuming 7.00 g of Magnesium completely react according to the above Eq'N,

    asked on December 18, 2016
  72. algebra

    Elimination method or substitution method. 1. 3/5x = 1/2y + 11 2. 3x + 8y + 13

    asked on December 14, 2016
  73. Science

    Each heating element has a resistance of 5 Ω. The current passing through each element is 0.4. Calculate the total resistance of the six heating elements.

    asked on December 14, 2016
  74. math

    A restaurant offers seven different main courses,,eight types of drinks and four kind of desserts. How many different meal consisting of main course,a drink and a dessert does the restaurant offer?

    asked on December 12, 2016
  75. chemistry

    Fe2+ is oxidized to Fe3+ and CrO4is reduced to Cr3+ using an unknown sample containing Fe2+ and 0.04322M K2CrO4 solution in a redox titration. I first need to balance the formula, but I don't know what to do with the potassium.

    asked on December 3, 2016
  76. Math

    Two hot air balloons are in flight above a field. The first Balloon is 30 meters above the ground rising 25 meters per minute. The Second Balloon is 300 meters above the ground descending 20 meters per minute. When will the 2 balloons be at the same

    asked on November 21, 2016
  77. math 9

    Given Parallelogram ABCD with AB=(3x-5)cm, BC=(2y-7)cm, Cd=(x+7)cm, AD=(y+3)cm

    asked on November 13, 2016
  78. Chemistry

    How many electrons in an atom could have these sets of quantum numbers? n=2 n=5, l=3 n=6, l=1, ml=-1

    asked on November 13, 2016
  79. chemistry

    the word "proof" on alcoholic beverages is defined as twice the percentage by volume. How many ml of alcohol are in a one-liter bottle of 80-proof gin?

    asked on November 12, 2016
  80. chemistry

    how much solute are present in a solution that contains 100.0g of water, and is 9.0% by weight sodium bicarbonate?

    asked on November 12, 2016
  81. chemistry

    how many grams of potassium nitrate are needed to prepare 250.0ml of a 0.03M potassium nitrate solution?

    asked on November 12, 2016
  82. chemistry

    calculate what volume of sulfuric acid solution(specific gravity=1.07;and containing 10%sulfuric acid by mass)contains 18.50g of pure sulfuric acid at a temperature of 25 Celsius.

    asked on November 12, 2016
  83. chemistry

    what volume of a 0.20M potassium sulfate solution contains 57g potassium sulfate?

    asked on November 12, 2016
  84. chem 15

    The hardness of water (hardness count) is usually expressed as parts per million (by mass) of calcium carbonate. What is the molar concentration of calcium ions in a water sample with a hardness count of 175ppm?

    asked on November 8, 2016
  85. chem 15

    A bottle of a certain ceramic tile cleanser, which is essentially a solution of hydrogen chloride, contains 130 g of HCl and 750 g of water. What is the percent by mass of HCl in this cleanser?

    asked on November 8, 2016
  86. Statistics

    The Citiburg Parks Department has just installed 1100 new lightbulbs with an expected mean lifespan of 64 months and a lifespan standard deviation of 8 months. Assuming normally distributed bulb failure, how many bulbs will need to be replaced after 49

    asked on October 29, 2016
  87. Statistics

    The Townville Parks Department has just installed 1900 new lightbulbs with an expected mean lifespan of 75 months and a lifespan standard deviation of 12 months. Assuming normally distributed bulb failure, how many bulbs will need to be replaced after 53

    asked on October 29, 2016
  88. algebra

    find the x-intercepts, f(x)=-9x^2-48x-64

    asked on October 24, 2016
  89. Math

    How many 10-inch pieces can be cut from a 6-foot piece of shelving?

    asked on October 13, 2016
  90. math

    amara rode her bicycle 8 miles in 0.5 hours.what was the average rate that she rode her bicycle in miles per hour?

    asked on September 29, 2016
  91. Geometry

    A map has the scale 2.5 inches:.75 miles. The distance from east to west is 6 inches what is the distance in miles

    asked on September 29, 2016
  92. Calculus

    1. Use a graph to estimate the limit. Use radians unless degrees are indicated by θ°. (Round your answer to four decimal places.) lim θ → 0 θ/tan(7θ) 2. Assuming that limits as x → ∞ have the properties for limits as x → c, use algebraic

    asked on September 28, 2016
  93. Chemistry

    Write the net ionic equation for the equilibrium that is established when ammonium nitrate is dissolved in water. (Use H3O+ instead of H+)

    asked on September 27, 2016
  94. Social Studies

    What were some of the advantages the continental army had over the British? Select all that apply. Fighting on familiar territory*** A large navy More troops*** Better supplies

    asked on September 23, 2016
  95. Science

    A family is planning to build a raised planting area using a blend of peat moss, mulch, and a rich organic soil in which to grow the plants. they have been told first to place on the ground a layer of material that will allow for a proper drainage each

    asked on September 20, 2016
  96. algebra

    90 students from three different classes, A, B, and C are going on a field trip. Class A has 32 students and Class B has 28 students. Write an equation to describe the situation.

    asked on September 5, 2016
  97. Chemistry

    The homework question said "which 2nd row element has 6 valence electrons and a valence of 2?" I don't really understand the question, because oxygen would be the element with the 6 valence electrons, but wouldn't that mean that it has a valence of 6? Does

    asked on September 2, 2016
  98. math

    Sam is one-third as old as his brother. In six years Sam will be one-half as old. How old is Sam now?

    asked on August 11, 2016
  99. Maths

    How would you solve the equation: 15 = 2x + y

    asked on July 23, 2016
  100. Math - Transformations

    State the transformation for g(x) = -2 (2x - 4)³ - 1 Would it be a vertical stretch by a factor of 2 a reflection in the x-axis a horizontal stretch by a factor of 1/2 a translation 4 units right and 1 unit down Am i right?

    asked on July 11, 2016


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