# mark

Most popular questions and responses by mark
1. ## chem

In a solution prepared by mixing CH3OH with H2O the major species pesent are 1. a. CH3+, OH, and H2O 2. b. CH3O, H+, and H2O 3. c. CH3OH and H2O 4. d. CH3OH, H+, and OH I know i have to get an equation having trouble doing that!! please help!!

2. ## geometry

One endpoint of a line segment is (8, −1). The point (5, −2) is one-third of the way from that endpoint to the other endpoint. Find the other endpoint.

3. ## Physics

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is its acceleration? A. 0.21 B. 0.46 C. 0.64 D. 0.78 E. 0.97 acceleration= change in velocity/change in time and the velocity= change in displacement

4. ## Chemistry

A gas sample at STP contains 1.15 oxygen and 1.55g nitrogen. What is the volume of the gas sample? the answer 2.04. I want to know how to get the that answer

5. ## Chemistry

Consider the generic reaction: 2 A(g)+ B(g)--> 2C(g). If a flask initially contains 1.0 atm of A and 1.0 atm of B, what will be the pressure in the flask if the reaction proceeds to completion? (Assume constant volume and temperature.) answer is 1.5atm how

6. ## Physics

The speed of a projectile when it reaches its maximum height is 0.42 times its speed when it is at half its maximum height. What is the initial projection angle of the projectile?

7. ## Art

A container is decorated with images of Egyptian gods and placed inside a tomb. What is the likely function of this object, given what you know about Egyptian culture? A. This container was probably designed to protect the internal organs of the dead

8. ## Physics

Vector C has a magnitude 25.8 m and is in the direction of the negative y-axis. Vectors A and B are at angles α = 41.9° and β = 25.2° up from the x-axis respectively. If the vector sum A B C = 0, what are the magnitudes of A and B?

Marianne buys 16 bags of potting soil that comes in 5/8 -pound bags. A. How many pounds of potting does Marianne buy? 10 B. If Marianne’s father calls and says he needs 13 pounds of potting soil, will 4 more bags be enough to cover the extra soil needed?

10. ## Chemistry

rank the gases Ar, N2,CH4, and C2H6 in order of the increasing density at STP answer: CH4

11. ## Chemistry!!!!!!!!

A sample of Xe takes 75 seconds to effuse out of a container. An unknown gas takes 37 seconds to effuse out of the identical container under identical conditions. What is the most likely identity of the uknown gas the answer is O2. How do you solve this?

12. ## Physics

An aerialist on a high platform holds onto a trapeze attached to a support by an 8.0-m cord. (See the drawing.) Just before he jumps off the platform, the cord makes an angle of 41° with the vertical. He jumps, swings down, then back up, releasing the

13. ## Physics

A car is traveling on a level horizontal rode comes to a bridge during a storm and finds the bridge washed out. The driver must get to the other side, so he decides to try leaping it with his car. The side of the road the car is on 21.3m above the river,

14. ## Social Studies help

What is a cradle-to-grave system? A. a system of state-run hospitals and nursing homes B. an association of doctors and nurses C. an association of nursery schools and public schools D. a system of basic services for every stage of life **

15. ## Chem

There are three questions in particular that I am having problems with. Here they are 1. A standard solution of FeSCN2+ is prepared by combining 9.00 mL of 0.200 M Fe(NO3)3 w/1.00 mL of 0.0020 M KSCN. The equilibrium concentration of FeSCN2+ ([FeSCN2+]std)

16. ## Language Arts

What impact did your Independent Reading selection have on you as a reader? Would you recommend your selection to a friend? Why or why not? Support your response with at least two pieces of evidence from your Independent Reading selection. Be sure to give

17. ## Chemistry

For which element is the gaining of an electron most exothermic? a)Li b)N c)F d)B *explain

18. ## Social Studies

1. Which statement best describes nations? A. must follow the laws set by the United Nations. B. Nations have less political power than do regional organizations. C. Nations interact almost exclusively with other nations in their region, D. Nations have

19. ## Chemistry

which gas has the greatest kinetic energy at STP? a)He b)Ne c)Ar d) None of the above(All have the same kinetic energy) how do I solve for this?

20. ## Chemistry

which gas sample has the greatest volume at STP? a)10.0g Ar b)10.0g Kr c) 10.0 g Xe d) none of the above (They all have the same number)

21. ## Trigonometry

two airplanes leave an airport at the same time one hour later they are 189km/hr apart. if one plane traveled 168km/hr and the other traveled 244km/hr for the hour what is the angle between their flight path

22. ## Chemistry

Upon heating 134 g MgSO4 · 7 H2O: (a) how many grams of water can be obtained? (b) how many grams of anhydrous compound can be obtained?

23. ## physics

A 4.00 kg block is pushed along the ceiling with a constant applied force of 85.0 N that acts at an angle of 55.0° with the horizontal, as in the figure below. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction

24. ## Statistics

A survey of 250 lobster fisherman found that they catch an average of 32 pounds of lobster per day with a standard deviation of four pounds. If a random sample of 30 lobster fisherman is selected, what is the probability that their average catch is less

25. ## Math help

Paul is painting a square wall with an area of 115 square feet. To the nearest foot, what is the length of the wall? (1 point) 11 29 ** 42 58

26. ## English-tenses

Hello I have key answers for the following tasks but I would like a native speaker to explain to me the uses of tenses here.The students have to put past tenses here. I am especially confused with the sentence beginning with The vases, which.... isn't it a

27. ## Social Studies (Check my work)

What factors contributed to the weakening and decline of Medieval Europe? My answer: In the 14th century, there was a disease called the black death. It weakened Medieval Europe a lot because it killed millions of Europeans. Is this good?

28. ## algebra 2

what is the quotient in simplified form? State any restrictions on the variable. (6-x)/x^2+3x-28 divided x^2-36/x^2+5x-36

29. ## SCIENCE

What type of bonding holds the compound, sodium cyanide, together? The CN bond is covalent. The Na to CN bond is, in most minds, an ionic bond. The electronegativity of C is about 2.1 and that of Na is about 1; therefore, with a difference of about 1 it is

30. ## geometry

Name a point that is between 50 and 60 units away from (7,-2) and state the distance between the two points.

31. ## statistics

John Davis, a manager of a supermarket, wants to estimate the proportion of customers that will be using food stamps at his store. How large a sample is required to estimate the true proportion to within 3% with 98% confidence?

32. ## history

Which identifies a revival of classical art, literature, and scholarship that spanned the 14th to 17th centuries in Europe? Romanticism Renaissance Scientific Revolution Reformation Is It Renaissance?

33. ## Geometry

The base of a right prism is a rhombus with a side of 10 cm and an altitude of 9.6 cm. Find the diagonals of the prism if the altitude of the prism is 12 cm.

34. ## physics

The front 1.20 m of a 1,350-kg car is designed as a "crumple zone" that collapses to absorb the shock of a collision. (a) If a car traveling 21.0 m/s stops uniformly in 1.20 m, how long does the collision last? s (b) What is the magnitude of the average

35. ## calculus

at a given instant the legs of a right triangle are 5cm and 12 cm long. if the short leg is increasing at the rate of 1cm/sec and the long leg is decreasing at the rate of 2cm/sce, how fast is the area changing

36. ## Chemistry

15.00mL sample of a solution of H2SO4 of unknown concentration was titrated with 0.3200 N NaOH. The titration required 21.30mL of the base. What was the normality of the acid solution? what was the molarity of the acid solution?

37. ## Chem

Balance the chemical equation given below, and determine the number of grams of MgO needed to produce 15.0 g of Fe2O3. _MgO(s)+_Fe(s)->_Fe2O3(s)+_Mg(s) 1. a. 11.4 g 2. b. 3.78 g 3. c. 1.26 g 4. d. 0.0877 g I got equation balanced 3,2,1,3 just having

38. ## Chemistry

What are the concentrations of OH– and H in a 0.00070 M solution of Ba(OH)2 at 25 °C? Assume complete dissociation.

39. ## geometry/check my work

For triangle ABC , which transformation composition is Commutative? a) rotate 30 degrees and then translate 2 units down b) translate 5 units to the right and rotate 90 degrees c) reflect across the y-axis and then rotate 90 degrees d) reflect across the y

40. ## Physics

A 0.1-kg object is traveling to the right (in the positive direction) with a speed of 2 m/s. After a 0.2 s collision, the object is traveling to the left at 3 m/s. What is the magnitude of the impulse (in N-s) acting on the object? The answer must be

41. ## math

Which one of the following statements is true? If f is continuous on (a, b), then f attains an absolute maximum value and f attains an absolute minimum inside the interval (a, b). If f '(x) > 0 on the interval (a, b), then f is decreasing on the interval

42. ## Math

LongLast Inc. produces car batteries. The mean life of these batteries is 60 months. The distribution of the battery life closely follows the normal probability distribution with a standard deviation of 8 months. As part of its testing program, LongLast

43. ## Chem

What is the formula mass in amu of KNaC4H4O6 *4H2O Is it 282.09 amu? What is the charge on the tartrate anion? How do I do this?

44. ## Chemistry

What is the empirical formula of a hydrocarbon that contains 89.94% C by mass?

45. ## Trigonometry

a boat travels on a course of bearing n 37 10' W for 79.5 miles. How many miles north and how many miles west has the boat traveled?

46. ## Chemistry

for each of the following acid-base reactions calculate the mass (in grams) of each acid necessary to completely react with and neutralize 4.85g of the base solution 1)2HNO3(aq)+ Ca(OH)2 (aq)> 2h20(l)+ Ca(NO3)2 2) H2SO4(aq)+ 2KOH(aq)---> 2H2O(l)+ K2SO4

47. ## Biochem

What is the maximum amount of ethanol (in millimoles) that could theoretically be produced under the following conditions? Condition: A cell-free yeast extract is placed in a solution that contains 3.50 × 102 mmol glucose, 0.30 mmol ADP, 0.30 mmol Pi,

48. ## College Chem

How many molecules of CH3OH will contain 3.20 x 10^23 H atoms?

49. ## physics

A storage tank at stp contains 18.5kg of nitrogen. What is the volume of the tank and what would the pressure be if you added another 15kg of nitrogen at the same temperature?

50. ## Language Arts

The football team cannot play ____ best when it is so hot. A. its ** B. our C. their D. you're I had this question in a language arts meeting with my teacher but I forgot the answer. I know that she talked about it being a trick question though so I'm not

51. ## Calculus

Use the Left and Right Riemann Sums with 80 rectangle to estimate the (signed) area under the curve of y=e^(3x)−5 on the interval of [10,20]. Write your answer using the sigma notation

52. ## chemistry

A voltaic cell is contructed in which a copper wire is placed in a 1.0 M Cu(NO3)2 solution and a strip of gold i placed in a 1.0 M AuNO3 solution. The measured potential of the cell is found to be 1.36V and the copper electrode is negative. The Ered for

53. ## calculus

Use the Left and Right Riemann Sums with 100 rectangle to estimate the (signed) area under the curve of y=−2x+1 on the interval [0,50]. Write your answer using the sigma notation.

54. ## Math

Ricky took a survey in the fifth grade and found that 2/3 of the students ride the bus to school and 1/4 of the students walk. What fraction of the fifth grade students either ride the bus or walk to school?

55. ## Chemistry

1.Arrange the following oxides in the order of increasing basicity. -Al2O3 -B2O3 -CaO -Ga2O3 -In2O3 -RaO 2.Arrange the following oxides in the order of most basic to most acidic. -Al2O3 -Cl2O7 -Cs2O -N2O5 -Na2O -P2O5 -SO3

56. ## US History

According to Black Elk, what atrocities took place at Wounded Knee? How did President Harrison describe these atrocities? Whom did Black Elk blame for the Wounded Knee Massacre? Whom did Harrison blame? According to President Harrison, what was the future

57. ## Physics

Displacement is which of the following types of quantities? A. vector B. scalar C. magnitude D. dimensional My answer is A. vector...I just want to confirm this is the correct answer.

58. ## physics

a 2.00 m tall basketball player is standing on the floor 10 m from the basket. if she shoots the ball at a 40 degree angle with the horizontal at what initial speed mjust he throw the basketball so that it goes through the hoop without striking the

59. ## Chemistry

A 255mL gas sample contains argon and nitrogen at a temperature of 65 degrees celsius. The total pressure of the sample is 725mmHg and the partial pressure of argon is 231 mmHg. what mass of nitrogen is present in the sample?

60. ## Chemistry

A gas mixture in a 1.55L at 298K container contains 10.0g Ne and 10.0g Ar. Calculate the partial pressure " in atm" of Ne and Ar in the container

61. ## physics

A cube of ice is take from the freezer at -8.5C and placed in a 95g calorimeter aluminum cup containing 310g of water at 20degC. The final situation is observed to be all water at 17degC. What was the mass of the ice cube?

62. ## GT

A GAS EXPANDS IN VOLUME FROM 26.7 ML TO 89.3 ML AT CONSTANTTEMPERATURE. CALCULATE THE WORK DONE (IN JOULES) IF THE GASEXPANDS (A) AGAINST A VACUUM,(B) AGAINST A CONSTANT PRESSUREOF 1.5 ATM, AND (C) AGAINST A CONSTANT PRESSURE OF 2.8 ATM.

63. ## Chemistry

Will 1 L of 1 M NaCl contain more chloride ions than 0.5 L of 1 M MgCl2 explain. One liter of 1 M NaCl contains________ mole(s) of NaCl, therefore_______ mole(s) of chloride ions. 0.5 L of 1 M MgCl2 contains__________ mole(s) of MgCl2, therefore_________

64. ## Physics

A mortar shell is launched with a velocity of 100m/s at an angle of 30 degree above the horizontal from a point on a cliff 50m above a level plain below. How far from the base of the cliff does the mortar shell strike the ground?

65. ## Physics

A pistol is fired horizontally toward a target 120 m away but at the same height. The bullet's velocity is 200 m/s. How long does it take the bullet to get to the target? How far below the target does the bullet hit? please explain why you used the formula

66. ## Chemistry

the distance from the sun to earth is 1.496 x10 ^8 km. how long does it take light to travel from the sun to earth How do you solve this?

67. ## Math

You complete 3 centimeters on your necklace in an hour. Each hour after the first,you triple the length of the necklace. Write an expression using exponents for the length of the necklace after 3 hours.Then find the length.

68. ## Stats

In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. Grades are to be assigned according to the following rule: The top 10% receive A's. The next 20% receive B's.

69. ## Physics

A cart traveling at 0.3 m/s collides with stationary object. After the collision, the cart rebounds in the opposite direction. The same cart again traveling at 0.3 m/s collides with a different stationary object. This time the cart is at rest after the

70. ## US History

Discuss the different approaches of the federal government toward the Plains Indians

71. ## Math-How do I do this problem?

An inverted conical tank (with vertex down) is 14 feet across the top and 24 feet deep. If water is flowing in at a rate of 12 ft3/min, find the rate of change of the depth of the water when the water is 10 feet deep.

72. ## Statistics Question (Confidence Interval)

A sample of 15 recent college graduates found that starting salaries for attorneys in New York City had a mean of $102,342 and a standard deviation of$21,756. Construct a 95% confidence interval for the average starting salary of all attorneys in the

73. ## Math

The bottom 30% of the students failed an end of semester exam. The mean for the test was 130 and the standard deviation was 27. What was the passing score?

74. ## physics

juana slides a crate along the floor of the moving van the coefficient of kinetic friction between the crate and van floor is 0.120 the crate has a mass of 56.8 kg and juana pushes with horizontal force of 124 N. if 74.4 J of work are done on crate and the

75. ## Math

I need help! I am confused! Algebra solve using substitution or elimination.10x-15y=10 4x+6y=0

76. ## Calculus

Find the points on the curve y=x2+2 closest to the point (0,3). Enter the coordinate with the smallest x-value first and round to the nearest 4 decimal places.

77. ## chemistry

41. Ethyne, C2H2, used in welding react with oxygen as shown below.

78. ## Physics

A 20-cm-diameter cylinder that is 40 cm long contains 50 g of oxygen gas at 20C. What is the number density of the oxygen? in m^-3 What is the reading of a pressure gauge attached to the tank? in kPa

79. ## Physics

I have tried to solve this problem in multiple ways, but i keep getting it wrong please help A 48.0 {\rm kg} ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 1.50 turns each second. The distance from

80. ## Physics

A skier launches off a ski jump with a horizontal velocity of 25.3 m/s (and no vertical velocity component). a) What is the magnitude of the horizontal component of her velocity the instant before she lands 1.95 s later? b) What is the magnitude of the

81. ## Geometry

BC has endpoints B(5,9) and C(-4,-3). Find the coordinates of the midpoint of BC.

82. ## Statistics

Reginald Brown an inspector from the department of weights and measures, weighs 15 eighteen-ounce cereal boxes of corn flakes. he finds their mean weight to be 17.78 ounces with a standard deviation of .4 ounces. are the cereal boxes lighter than they

83. ## Educational Tech

Which of the following should you use to change text size, color, and font face to make a section label stand out? A. Overtype B. Heading Styles C. text wrapper ** D. Footnote

84. ## chemistry

i am working on a practice worksheet and need help with a few i can not understand. please and thank you. I have to post them separately sorry 49.how many grams of water are needed to completely hydrolyze 30.8 g of the ester? A.0.416 g B.30.8 g C.11.3 g

85. ## Math

The sides of the triangle at right are formed by the graphs of 3x+ 2y = 1, y = x − 2, and −4x+ 9y = 22. Is the triangle isosceles? How do you know?

86. ## Physics

A typical laboratory centrifuge rotates at 4100 rpm. Test tubes have to be placed into a centrifuge very carefully because of the very large accelerations. (a) What is the acceleration at the end of a test tube that is 11 cm from the axis of rotation?

87. ## Language Arts

Choose the phrase that would best replace the italicized words in the sentence. the ringing of the school bell was "music to my ears" A. a pleasant melody B. a band playing loudly C. a welcome sound** D. a warning signal

88. ## HCC

if x=4 which of the following expression DOES NOT equil 9?

89. ## English - Native speakers

Need a help from a native speaker of English. Can you fill in this text by using either Past Simple, Past Continuous or Past Perfect? You would really help a lot. Thank you When Craig Myers __________(buy) his restaurant, he got it for a very good price

90. ## math problem

A piece of wire 24 cm long is cut into two pieces and each piece is bent to form a square . Find the lenght of each piece of wire in order to maximize the sum of the area of the two squares?

91. ## Statistics

Two cards are drawn in succession from a deck without replacement. What is the probability that both cards are greater than 2 and less than 8?

92. ## Chemistry

Which of the following compounds contains 57.5% sodium by mass? *NaI *NaOH *NaHCO3 *NaSO3

93. ## Physics

A stone is thrown vertically upward with a speed of 21.0 m/s a)How fast is it moving when it reaches a height of 15.8 m b)How much time is required to reach this height?

94. ## Math

Explain It Why is 10-0=10, but 0/10=0? Explain

95. ## pre algebra

Lilliana is training for a marathon. She runs the same distance every day for a week. On Monday, Wednesday, and Friday, she runs 3 laps on a running trail and then runs 6 more miles. On Tuesday and Sunday, she runs 5 laps on the trail and then runs 2 more

96. ## Math

A farmer kept track of his cows and chickens by counting both the legs and the heads, if he counted 78 legs and 35 heads, how many cows and how many chicken did he own?

97. ## English

Take this kiss upon the brow! And, in parting from you now, Thus much let me avow — You are not wrong, who deem That my days have been a dream; Yet if hope has flown away In a night, or in a day, In a vision, or in none, Is it therefore the less gone?

98. ## economics

aztec enterprises depends heavily on advertising to sell its products. management at aztec is allowed to spend $2million monthly on advertising, but no more than this amount. each month, aztec spends exactly$2million on advertising. what is aztec's