# mark

Popular questions and responses by mark
1. ## 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

2. ## 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!!

3. ## 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

4. ## 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

5. ## Chemistry

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

6. ## 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?

7. ## 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

8. ## 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?

9. ## 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

10. ## 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.

11. ## 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?

12. ## 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?

13. ## 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?

14. ## 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

15. ## 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

16. ## 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.

17. ## 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?

18. ## 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?

19. ## 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

20. ## Algebra

Solve the polynomial equation by finding all real roots x^4+15x^2-16 Many thanks

21. ## 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

22. ## Trig/Pre-Calc

A bird is flying 30 mph in a direction 30 degrees south of east. Affecting the flight of the bird is a wind blowing from the northeast to the southwest at a speed of 10 mph. What is the resulting speed of the bird?

23. ## 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

24. ## science

A heat engine draws 800J of heat from its high temperature source and discards 450J of exhaust heat into its cold temperature reservoir during each cycle.How much work does this engine perform per cycle?

25. ## 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

26. ## math

The sum of my ones and tens digit is 10. My tens digit is greater than my ones digit. I am a prime number. What number am I?

27. ## 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,

28. ## chemistry

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

29. ## Physics

A raindrop (mass 1.00 g) is travelling at a speed of 40m/s when it hits the surface of 100 g of water contained in a drinking glass. What is the change in temperature of the water in the glass if we assume that a) all the kinetic energy of the raindrop is

30. ## 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

31. ## 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

32. ## 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

33. ## electronic

A 1mm cross section of copper wire is isolated. The charge that flows through the cross section is Q t = 4t^2 + 5 How much current flows through the wire in 6 seconds?

34. ## Chemistry

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

35. ## Chemistry

Which molecule contains a polar covalent bond? a)C2H4 b)ZnS c)LiI d)NBr3 e)AgI

47. ## physics

A 88g arrow is shot from a bow whose string exerts an average force of 110n on the arrow over a distance of 78cm.What is the speed of the arrow as it leaves the string?

48. ## Chem

When 0.10 g of insulin is dissolved in 0.200 L of water, the osmotic pressure is 2.30 Torr at 20°C. What is the molar mass of insulin? I tried using the van't hoff equation, converting Torr into atm; but not sure how to do it. my teacher didn't really

49. ## US History

Camp meetings, like the one in the picture above, were thought to inspire which of the following? (picture showing crowds of people gathered around people in a forest) Men and women to give their lives to God ** Men and women to accept and pray for sinners

50. ## PHYSICS! HELIUM BALLON

Under standard conditions, the density of air is 1.293 kg/m3 and that of helium is 0.178 kg/m3. A spherical helium balloon lifts a basket plus cargo of mass 277.0 kg. What must be the minimum diameter of the spherical balloon?

51. ## 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.

52. ## Algebra

Some functions that aren't invertible can be made invertible by restricting their domains. For example, the function x^2 is invertible if we restrict x to the interval [0,inf), or to any subset of that interval. In that case, the inverse function is \sqrt

53. ## Statistics

Health issues due to being overweight affect all age groups. of children and adolescents 6-11 years of age,18.8% are found to be overweight. A school district randomly sampled 130 in this age group and found that 20 were considered overweight. at Alpha

54. ## Math (Algebra)

A jar contains x nickels and y quarters only. What percentage of the total number of coins are quarters?

55. ## finance

1. The U.S. ﬁnancial system is composed of: (1) policy makers, (2) a monetary system, (3) ﬁnancial institutions, and (4) ﬁnancial markets. Indicate which of these components is associated with each of the following roles: a. accumulate and

56. ## marketing

Binomial probability distributions are used in business, science, engineering, and other fields. Suppose you work for a marketing agency and have to create a television ad for Brand A toothpaste. The toothpaste manufacturer claims that 40% of the

57. ## Astronomy/Physics

I'd love thorough solutions to these problems, but simply providing the specific formulas that I should solve each part of the problem with would be really good too. :-) Thanks! Human energetics You are sitting down to study in the library. Let’s find

58. ## algebra

Solve the polynomial equation by finding all real roots g(x) = x^4 + 15x^2 -16 SO: (X^2+16) (X-1)....I'M STUCK THANKS

59. ## World History

In what part of the world did France and Britain go to war as part of the French and Indian War? West Africa North America South Asia Western Europe

60. ## Calculus

a pebble is dropped into a calm pond, causing ripples in the form of concentric circles. the radius r of the outer ripple is increasing at a constant rate of 1 root per second. When the radius is 4 feet, at what rate is the total area A of a disturbed