# jen

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.

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

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

4. ## Riddle

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

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?

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?

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

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.

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?

10. ## chemistry

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

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

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

13. ## chemistry

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

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

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.

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?

17. ## chemistry

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

18. ## chemistry

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

19. ## chemistry

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

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

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.

22. ## chemistry

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

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?

24. ## science

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

25. ## science

does p-chlorophenol soluble in sodium bicarbonate?

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.

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.

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

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?

30. ## math

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

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

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?

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

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

35. ## Algebra

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

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

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

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

39. ## CAlculuss

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

40. ## texas historty

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

41. ## texas historty

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

42. ## science

Why are the oldest rocks on earth on continental crusts?

43. ## Equality Studies

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

44. ## Equality Studies

Who are some prominent obese role models?

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.)

46. ## Algebra

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

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

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

49. ## Math

55÷11+7x(2+14)

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

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

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

53. ## math

zeros are real number? true or false

54. ## math

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

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?

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.

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

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

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

60. ## Math

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

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

62. ## English

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

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

64. ## stats.help!

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

65. ## Math7/8

ANNIKA HAS A SOCK FILLED WITH 3 RED MARBLES AND 5 GREEN MARBLES. WHAT IS THE PROBABILITY OF HER CHOOSING TWO RED MARBLES WITH AND WITHOUT REPLACEMENT?

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?

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

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

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?

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?

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,

72. ## algebra

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

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.

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?

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.

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

77. ## math 9

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

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

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?

80. ## chemistry

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

81. ## chemistry

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

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.

83. ## chemistry

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

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?

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?

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

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

88. ## algebra

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

89. ## Math

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

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?

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

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

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+)

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

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

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.

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

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?