# Questions Asked onSeptember 27, 2014

1. ## chemistry

Calculate the empirical formula for compound ethyl butyrate (pineapple oil): C, 62.04%; H, 10.41%; O, 27.55% Can someone show me the steps?

2. ## Trig

A railroad tunnel is shaped like a semiellipse as shown below. A semiellipse is shown on the coordinate plane with vertices on the x axis and one point of intersection with the positive y axis. The height of the tunnel at the center is 27 ft and the

3. ## Algebra

A building is 2ft from a 9ft fence that surrounds the property. A worker wants to wash a window in the building 13ft from the ground. he plans to place a ladder over the fence so it rests against the building. he decides he should place the ladder 8ft from

4. ## math

arnold has 24m of fencing to surround a garden, bounded on one side by the wall of his house. what are the dimensions of the largest rectangular garden that he can enclose? how do i solve this question please help step by step solutions please

5. ## Health Help?

1. A percentile rank represents the percentage of people who scored at or below the test score. True False 2. People who have high resting heart rates usually have high levels of cardiovascular fitness. True False 3. Resting heart rate is usually measured

6. ## chemistry

Determine the number of moles of H in 4.70mol H2O. Please help I tried different ways to do it and I got them all wrong.

7. ## chemistry

The half-life of oxygen-15 is 124 s. If a sample of oxygen-15 has an activity of 4800 Bq, how many minutes will elapse before it has an activity of 600 Bq?

8. ## World History Answer Check

1. How did the Committee of Public Safety identify enemies of the state? A: The Committee of Public Safety indentified enemies of the state by the people who were under suspicion of betraying France. 2. Did the French Revolution live up to the revolution's

13. ## chem

The electron in a ground state H atom absorbs a photon of wavelength 121.57nm, to what energy level does the electron move?

14. ## Chemistry

If you dilute 14.0mL of the stock solution to a final volume of 0.350L , what will be the concentration of the diluted solution? Before it, there was a question: How many milliliters of a stock solution of 5.60 M HNO3 would you have to use to prepare

15. ## chemistry

30 ml of sample of unknown strong base is neutralized after the addition of 12 ml of a 0.150 M HNO3 solution if the unknown base concentration 0.0300 M give the possible identities for the unknown base

16. ## chemistry

A 8.50-g sample of solid AlCl3·6H2O was heated such that the water turned to steam and was driven off. Assuming ideal behavior, what volume would that steam occupy at 1.00 atm and 100.0 °C?

17. ## chemistry

Suppose 1.2x10^3 kg of C is mixed with 2.4x10^5g oxygen gas and carbon dioxide forms. 1. write the reaction and balance 2.which reactant is the limiting reagent and which reactant is in excess 3. How many grams of carbon dioxide will be formed.

18. ## chemistry

How do you calculate the mass percent composition of nitrogen in NO2?

19. ## chemistry

Hydrogen gas produced by this reaction is typically collected via water displacement, during which time the hydrogen gas becomes saturated with water vapor. If 238.4 mL of gas with a total pressure 1.27 atm was collected via water displacement at 29.4 °C,

20. ## chemistry

Air is 78.1% nitrogen, 20.9% oxygen, and 0.934% argon by moles. What is the density of air at 22 °C and 760 torr? Assume ideal behavior.

21. ## chemistry

Imagine there is a tank of unknown gas that contains 53.31% carbon, 35.51% oxygen, and 11.18% hydrogen by mass. At 35.0 °C and 0.470 bar, 2.0 L of the gas has a mass of 3.3 g. Using this information, answer the following questions. a.) What is the

22. ## Chemistry

Please help! Calculate the standard change in enthalpy, ΔH°rxn, for the decomposition of calcium carbonate to calcium oxide CaCO3 (s) → CaO (s) + CO2 (g) Given that: ΔH°f CaCO3 (s) = -1206.9 kJ/mol ΔH°f CaO (s) = -635.1 kJ/mol ΔH°f CO2 (g) =

23. ## math

between which two square roots of integers can you find pi?

24. ## social statistics

a smoking researcher is interested in estimating the average age when cigarette smokers first began to smoke. Taking a random sample of 25, she determines a sample mean of 16.8 years and a sample deviation of 1.5 years. Construct a 95% confidence interval

25. ## physics

If the acceleration due to gravity on the Moon is 1/6 that what is on the Earth, what would a 100 kg man weight on the Moon? If a person tried to simulate this gravity in an elevator, how fast would it have to accelerate and in which direction?

26. ## physics

A basketball player throws the ball at a 53degree angle above the horizontal to a hoop which is located a horizontal distance L = 2.4 m from the point of release and at a height h = 0.9 m above it.What is the required speed if the basketball is to reach

27. ## chemistry

in HNO3 titration, you add few drops of phenolphthalein indicator to 50.0 mL of acid in a flask. you quickly add 20.00 mL of 0.0547 M NaOH but overshoot the end point, and the solutions turn deep pink. instead of starting over, you add 30.00 mL of acid,

28. ## chemistry

2NiS2(s)+5O2(g)=2NiO(s)+4SO2(g) 1. how many kilograms of NiO would be formed from the reaction of .0125 mol of NiS2? 2. How many grams of O2 are needed to cmpletely react with 3.74 g of NiS2.

29. ## Math

3x9=9x=( )= ( )

30. ## CHEM

What is the IUPAC name for the molecule shown here? H I \ / C=C / \ I H

31. ## physics

A small toy airplane is flying in the xy-plane parallel to the ground. In the time interval t=0 to t=10.0 s, its velocity as a function of time is given by υ⃗ =(1.50m/s2)ti^+[13.0m/s−(2.00m/s2)t]j^.

32. ## chemistry

A 8.80-g sample of solid SnCl2·2H2O was heated such that the water turned to steam and was driven off. Assuming ideal behavior, what volume would that steam occupy at 1.00 atm and 100.0 °C?

Bethany Link delivers parts for several local auto parts stores. She charges clients $0.75 per mile driven. She has determined that if she drives 2,100 miles in a month, her average operating cost is$0.55 per mile. If Bethany drives 4,200 miles in a

34. ## Algebra 1

Adding and subtracting polynomials. (6-t-t^4) + (9t+t^4) How do you solve this problem?

35. ## chemistry

a student mixes 4 reagents together thinking that the solution will neutralize each other . The solution is mixed together are 50 ml of 0.100 M of HCL and 100 ml of 0,200 M of nitric acid 500 ml of 0.0100 M ca hydroxide and 200 ml of 0.100 M rubidium

36. ## physics

The barrel of a rifle has a length of 0.97m. A bullet leaves the muzzle of a rifle with a speed of 601m/s. What is the acceleration of the bullet while in the barrel?

37. ## physics

If a 1500 kg car stopped from an in 5.6 seconds with an applied force of 5000 N, how fast was it initially traveling?

38. ## physics

An acoustic burglar alarm consists of a source emitting waves of frequency 28.0 kHz. What is the beat frequency between the source waves and the waves reflected from an intruder walking at an average speed of 0.095 m/s directly away from the alarm?

39. ## physics

An ambulance with a siren emitting a whine at 1600 Hz overtaken and passes a cyclist pedaling a bike at 2.44 m/s. After being passed, the cyclist hears a frequency of 1590 Hz. How fast is the ambulance moving?

40. ## Physics

A car travels 120 meters in one direction in 20 seconds. Then the car returns ¾ of the way back in 10 seconds. a) Calculate the average speed of the car for the first part of the trip. b) Find the average velocity of the car.

41. ## History

Why did the Hittites and others migrate from Central Asia to Mesopotamia? A- They needed more land for growing populations B- They were enlarging their empires C- The Persian army drove them out D- Climate change brought a mini ice age to Asia I think A.

42. ## Statistics

X is a normally distributed random variable X with mean 15 and standard deviation 0.25. Find the values xL and xR of X that are symmetrically located with respect to the mean of X and satisfy P(xL < X < xR) = 0.80. (Hint. First solve the corresponding

43. ## physics

A geosynchronous satellite is one that appears to be fixed in the sky, a condition useful for telecommunications. If such a satellite orbits the earth at an altitude of 33000 km above the earth's surface, what is its centripetal acceleration? The radius of

44. ## Physics

Consider two toy cars. Car A starts from rest and speeds up with constant acceleration for a time delta t until it reached a speed of v and then continues to travel at this speed. At the moment car A reaches its maximum speed, car B, starting at rest from

45. ## physics

A pot with a flower falls out of a window box in a tall apartment building. It passes the top of a particular window with a velocity of -1.7 m/s. It passes the bottom of this window 0.2800 s later? How tall is the window (watch sign)?

46. ## chemistry

A 4.78-g sample of aluminum completely reacts with oxygen to form 6.67 g of aluminum oxide Use this data to calculate the mass percent composition of aluminum in aluminum oxide. (Sorry need help with this!)

47. ## physics

. A 90cm uniform lever has a load of 30N suspended at 15cm from one of its ends. If the fulcrum is at the centre of gravity, calculate the force that must be applied at its other end to keep it horizontal

48. ## math

Which is greater, the increase in miles driven between 1998 and 1999 or between 1999 and 2000? What is that increase? Data given: 1998-75,288 miles 1999-117,391 miles 2000-126,304 miles

49. ## Chemistry

Please help me! I don't know how to do this at all. Calculate the enthalpy for the reaction: NO (g) + O (g) → NO2 Given the following known reactions: NO(g)+O3 (g)→NO2 (g)+O2 (g) 03 (g)→1.5O2 (g) O2 (g)→2O(g) ΔH°=-198.9kJ ΔH°=-142.3kJ

84. ## physics

A car travelling at 60 km/h hits a bridge abutment. A passenger in the car moves forward a distance of 67 cm (with respect to the road) while being brought to rest by an inflated air bag. What force (assumed constant) acts on the passenger¡¦s upper

85. ## Biology

Why does biomass decrease as we move up the biomass pyramid?

86. ## history

There were many examples that inspired the reform-minded spirit after 1900. Which was not an example? Muckrakers Plessy v. Ferguson Triangle Shirtwaist Factory fire The Jungle

87. ## physics

It takes the elevator in a skyscraper 4.5s to reach its cruising speed of 11m/s . A 70kg passenger gets aboard on the ground floor. What is the passenger's weight before the elevator starts moving? What is the passenger's weight while the elevator is

88. ## US History

Women made many contributions during World War I. Which area did they make the least impact? Nurses in the war Heavy industry Maintaining farms Truck drivers

89. ## English

How do I turn this into a really good thesis statement? In the myth " When Grizzlies Walked Upright" explain how the bears lived in relation to each other before and after the introduction of the female into their clan, and explain how both the bears and

90. ## physics

A spacecraft is in orbit close to the moon's surface. The centripetal acceleration is 1.6 m/s^2. If the radius of the moon is about 1.7 x 10^6 m, determine: a)the orbital speed b)the period of the orbit

91. ## Material Sciences

A steel bar of length L and cross-sectional area A is fitted between rigid supports. Write an expression for the stress in the bar when the temperature is raised by an amount ΔT. Write your answer in terms of α,E and ΔT. Is the stress compressive or

92. ## history

In the Seven Years’ War, Spain fought on the side of France right? Native Americans were unable to resist successive waves of European immigrants at least partially because they were divided among themselves. this is true right?

93. ## Math 2--questions

7. Find the sum. –14 + 7 + (–3) –24 –18 –10 *** –4 8. A scuba diver descends 350 feet and then another 120 feet. Express the diver’s final depth as an integer. –420 ft 420 ft ** –470 ft 470 ft

94. ## Simplify Practice.

Write the difference 30 – (–12) as a sum, then simplify. Evaluate the following expression. Show all steps. 18 + 6m for m = 2

95. ## physics

In a TV set, an electron beam moves with horizontal velocity of 2.5 × 107 m/s across the cathode ray tube and strikes the screen, 44 cm away. The acceleration of gravity is 9.8 m/s2 . How far does the electron beam fall while traversing this distance?

96. ## math

what does this question mean : Sketch a graph to show four graphs in each family. a) y=(x-3)(x+6) b) y= (x+1)(x+1)

97. ## Math

Using the following cash flows for projects A and B, use payback period, discounted payback period, NPV, IRR, and MIRR to see if these are good projects or not. > Project A: (283,000); 46,000; 89,000; 104,000; 123,000; 187,000; and 72,000 > Project B:

98. ## Engineering science

A water pump produces 9KL of water per hour at a height of 70 m above the pump.The pump is driven by a 3 KW electric motor.calculate. 1) The work done per hour 2) The work done per minute

99. ## CHEMISTRY

Does a molecular compound in water have hydration or have ionization ?

100. ## Science

a car is moving at 80km/hr and slows down to 13km/hr in 9.75 seconds. Calculate the car's acceleration Formula for acceleration= Final speed-Initial/Time

101. ## Math

What is half of 850

102. ## quanta tive skills and reasoning

In a class of 250 students it was found that 140 took math 85 took psychology and 65 took both math and psychology how many students in the class took math or psychology?

103. ## physics

A basketball is thrown at 45° to the horizontal. The hoop is located 4.4 m away horizontally at a height of 1.1 m above the point of release. What is the required initial speed?

104. ## Math

Explain why the expression (x^2￼+ 6) ------- (x^3+3) , which seemingly can be simplified, actually cannot be simplified.

105. ## English

This is for "When Grizzlies Walked Upright" explain? How did the bears lived in relation to each other? How did the bears lived in relation to each other before and after the introduction of the female into their clan How did both the bears and the female

5pi over 4

107. ## algebra

1 cm to the third of aluminum weighs 2.7 grams if a sheet is 0.003 8 find the weight

108. ## physics

An airplane is 50,000 m above an observer and 2.1 km to the west of them and 1.5 km to the north of you. Determine the angle to the plane in the x – y axis and the total distance to the plane from you. Choose the x-axis east, y axis north, and z axis up.

109. ## algebra

on an expressway, the recommended safe distance between cars in feet is given by 0.019v^2+v+14, where v is the speed of the car in miles per hour. Find the safe distance when the following takes place( round answer to three decimal places). v=35 mph

110. ## Finance

1. What happens to companies with high operating leverage when the market declines? What happens when the market expands?

111. ## Finance

What happens to the cash flow statement for a company operating on a calendar year when a sale is made in December but the firm isn’t paid until the following January?

112. ## math

The sides a,b,c of a triangle are such that a^2+b^2+c^2=ab+bc+ca.What type of triangle is it?

113. ## Biology

1. Describe 2 methods of viral infection 2. How can a virus be helpful to its host? Thank you:)

114. ## Material Sciences

The energy-separation curve for two atoms, a distance, r, apart is: U(r)=−A/r^m+B/r^n Derive an expression for the equilibrium spacing, r0, as a function of A, B, m, and n.

115. ## physics

A ball is thrown at 14 m/s at 57° above the horizontal. Someone located 30 m away along the line3 of the path starts to run just as the ball is thrown. How fast, and in which direction, must the catcher run to catch the ball at the level from which it was

116. ## Pre-Calc

Solve the system of equations using either the substitution method or the multiplication/addition method answer: 3x+2y=14 2x-4y=4

117. ## Math plz help.

Write the letter of the property shown in each example. a. Commutative Property of Multiplication b. Identity Property of Multiplication c. Associative Property of Addition d. Identity Property of Addition e. Associative Property of Multiplication f.

118. ## English

What's the difference between the phrase: "It is not about you", and "It has nothing to do with you" Or do they necessarily mean the same?

119. ## physics

A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.75 104 m/s, and the radius of the orbit is 5.15 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has

120. ## Math

Cal had 6 comic books. After he gave 1 comic book to each of his cousins, he had none left. How many cousins does Cal have?

121. ## math

what is the prime factorization of 140

122. ## math

If the area of a rectangle is 2,460 square inches, what are its dimensions?

123. ## Economics

Does this production possibilities curve reflect the law of increasing opportunity costs.explain

124. ## algebra 2

Solve each system of equation by grpahing? 3. y=-3x+6 2y=10x-36 4. y=-x-9 3y=5x+5

125. ## statistics

According to U.S. News & World Report data, in 1995 tuition costs at Indiana University, a public university, were $2,984 per year, while the tuition costs at the University of Evansville, a private university in Indiana, were$11,800 per year. In that

Wellington’s Funds Flow Statement (Statement of Cash Flows) Sources Earnings after taxes \$ 80 Depreciation 84 Decrease in accounts receivable 42 Increase in accounts payable 13 Increase in notes payable 196 Increase in accruals 22 Increase in long-term

127. ## Pre-Calc

Help please Find f(2) and f(a+h) when f(x)=3x^2+2x+4

128. ## Math

explain why the expression (x^2+6) / (x^2+3) which seemingly can be simplified, actually cannot be simplified.

129. ## astro

ProximaCentauriisapproximatelythesamedistancefromEarth(slightly less than 4.3 light years) as Alpha Centauri A, but it has an apparent magnitude of +11.05, compared to Alpha Centauri A’s magnitude of -0.01. How much more luminous is Alpha Centauri A than

130. ## history

Roosevelt addressed the struggles of industry with the National Industrial Recovery Act (NIRA). Which of the following was not one of the main components of this effort? African American labor assistance Public works projects National Recovery

131. ## algebra

on an expressway, the recommended safe distance between cars in feet is given by 0.019v^2+v+14, where v is the speed of the car in miles per hour. Find the safe distance when the following takes place( round answer to three decimal places). v=35 mph

132. ## Chemistry

500 g of Fe reacted with water to yield 4.2 g of H2. Fe3O4 was also produced in the reaction. What is the %yield of H2?

133. ## math

midpoint (4,13) endpoint (0,6). find the other endpoint

134. ## Math

1.) Find (f - g)(x) if f(x) = 2x - 5 and g(x) = 4. 2.) Given f(x) = 4 and g(x) = 2x - 1, find (f - g)(x). Thanks so much! :)

135. ## physics

A stone is thrown at 15 m/s an angle \theta below the horizontal from a cliff of height H. It lands 78 m from the base 6 s later. Find \theta and H.

136. ## math

I'm working on a school math project, and i need to make my own 2 plans, i know that you can split all 17.5 ct diamonds so that each pirate would get 4.375 ct diamonds but i want to know how i would split them up, like into to 1/2 s or 1/4 and i need

137. ## Math problems.

Use the order of operations to simplify the expressions in the next two questions. 15 – 6 • 9 ÷ 2 + 10 16. 4 • (6 + 3) + 5

138. ## Health

What are positive attributes?

139. ## chem

/***\ \___/ hexane with a double bong in position 1-2 with 2 ch3 one on top one on bottom what would be the name of this

140. ## Algebra 2

Please help me with this problem and can you write down the steps. y-1 ____ x+3 = 3/4 (equivalent ratio)

141. ## Health

What are example of a psychosomatic response, when talking about stress?

142. ## Math one question?

A scuba diver descends 350 ft and then another 225 ft. Express the diver’s final depth as an integer. –525 ft –575 ft 525 ft 575 ft

143. ## Algrebra

A rectangular field is 3 yards longer than twice its width. If the perimeter is 156 yards. How wide is the field? 3*2=6 6*2=12 6*2*12=156 ??

144. ## math

Find the sum of the first 60 terms of the arithmetic sequence whose first term is −15 and whose common difference is 7.

145. ## Algebra 2

y-1 ____ x+3 = -3/4 (equivalent ratio) can you explain the steps which you use to get this answer and why you use them . I am sorry I am a disable student and it hard some time to grasp this math fo rme.

146. ## Science

Suppose a geologist is studying two distinct areas next to a spreading ridge. The magnetic direction of the minerals in the oldest area is opposite to the magnetic direction of minerals in the newest area. a) Which area is closest to the center of the

147. ## math

A rocket ascends at an angle of 60.0˚ with the horizontal. After 1.00 min it is directly over a point that is a horizontal distance of 16.0 km from the launch point. Find the speed of the rocket.

148. ## chemistry

230Th+He____223Po+2 2H+----- please complete this equation

149. ## Physics

A bike wheels rotate 4 revolutions. How radiant has it rotates?

150. ## Calculus

Hello, my question is the following: The derivative of f(x) = ln(x) is given by f'(x) = 1/x. Find an equation of the tangent line to the graph y = ln(x) that passes through the point (0,0). So if I go through this using the typical method I use I have the

151. ## math

Identify the solution(s) of the system of equations, if any. x + 5y = 6 6x - 15y = 18

What happens to companies with high operating leverage when the market declines? What happens when the market expands?

153. ## physics

An electron in an atom has a speed of 2.2 × 10^6 m/s and orbits the nucleus at a distance of 5 × 10^-11m.a)What is its centripetal acceleration? b)A neutron star of radius 17 km is found to rotate at 5 revolutions per second. What is the centripetal

154. ## ap physics

2.7s , how far do you travel during this inattentive period?

155. ## chemistry

If 70.0 mL of water is added to 30.0 mL of 0.400 M solution of NaOH, what is the new concentration of NaOH?

156. ## Biology

What is the water potential of a 5.7 L water in which 2.1 moles of NaCl has been dissolved at 30 degrees celcisus? Help please? Can you show work as well? It'll be greatly appreciated. Thanks in advance.