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!!

asked on April 24, 2010
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.

asked on May 31, 2015
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

asked on July 16, 2008
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

asked on October 18, 2015
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

asked on October 18, 2015
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?

asked on June 24, 2015
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

asked on March 12, 2018
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?

asked on June 2, 2015
9. 6th Grade Math

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?

asked on September 16, 2014
10. Chemistry

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

asked on October 18, 2015
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?

asked on October 18, 2015
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

asked on May 29, 2012
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,

asked on March 22, 2017
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 **

asked on March 29, 2018
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)

asked on January 19, 2009
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

asked on September 30, 2017
17. Chemistry

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

asked on November 22, 2015
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

asked on August 31, 2017
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?

asked on October 18, 2015
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)

asked on October 17, 2015
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

asked on June 8, 2016
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?

asked on May 26, 2015
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

asked on February 21, 2016
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

asked on May 7, 2014
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

asked on October 29, 2017
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

asked on November 25, 2011
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?

asked on April 13, 2018
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

asked on May 31, 2018
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

asked on February 7, 2007
30. geometry

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

asked on May 31, 2015
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?

asked on May 4, 2014
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?

asked on November 6, 2018
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.

asked on June 24, 2015
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

asked on March 3, 2016
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

asked on December 4, 2008
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?

asked on October 5, 2015
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

asked on April 24, 2010
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.

asked on October 20, 2011
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

asked on April 5, 2017
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

asked on February 27, 2012
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

asked on February 3, 2015
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

asked on April 25, 2014
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?

asked on March 3, 2008
44. Chemistry

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

asked on September 18, 2011
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?

asked on September 11, 2015
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

asked on September 22, 2015
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,

asked on April 3, 2013
48. College Chem

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

asked on July 16, 2012
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?

asked on April 19, 2011
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

asked on December 12, 2017
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

asked on November 13, 2015
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

asked on July 17, 2010
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.

asked on November 13, 2015
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?

asked on November 21, 2016
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

asked on April 23, 2007
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

asked on March 30, 2016
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.

asked on July 16, 2008
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

asked on October 3, 2011
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?

asked on October 17, 2015
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

asked on October 17, 2015
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?

asked on April 24, 2011
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.

asked on July 20, 2015
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_________

asked on June 3, 2015
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?

asked on October 24, 2011
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

asked on June 9, 2015
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?

asked on October 25, 2015
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.

asked on September 16, 2014
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.

asked on November 18, 2016
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

asked on February 27, 2012
70. US History

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

asked on March 30, 2016
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.

asked on December 21, 2014
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

asked on March 14, 2012
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?

asked on December 7, 2016
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

asked on May 11, 2011
75. Math

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

asked on September 24, 2019
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.

asked on November 5, 2015
77. chemistry

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

asked on November 17, 2015
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

asked on April 25, 2012
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

asked on March 3, 2008
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

asked on October 16, 2015
81. Geometry

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

asked on November 6, 2012
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

asked on May 4, 2014
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

asked on August 31, 2017
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

asked on November 17, 2015
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?

asked on February 12, 2013
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?

asked on October 7, 2012
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

asked on September 8, 2017
88. HCC

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

asked on May 11, 2016
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

asked on December 12, 2011
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?

asked on March 21, 2013
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?

asked on May 3, 2017
92. Chemistry

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

asked on April 30, 2012
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?

asked on October 31, 2015
94. Math

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

asked on February 10, 2013
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

asked on October 19, 2017
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?

asked on July 10, 2017
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?

asked on February 2, 2016
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

asked on June 15, 2009
99. World History

What was the historic name of the Southeast Asian region that lies east of India and south or southwest of China? Indochina Mongolia Tibet Philippines B?

asked on August 3, 2018
100. statistics

The average age for licensed drivers in a county is µ= 42.6, σ= 12 and the distribution is approximately normal. A county police officer was interested in whether the average age of those receiving parking tickets in the county differed from that of the

asked on April 19, 2014