Thursday

October 23, 2014

October 23, 2014

Total # Posts: 577

**science-chemistry**

An aqueous solution of ammonium nitrite decomposes when heated to give off nitogen gas and water. This reaction can be used to prepare pure nitrogen gas. How many grams of ammonium nitrite must have reacted if 3.75 liters of nitrogen gas was colleced over water at 25˚C ...
*October 20, 2014*

**Chemistry**

An aqueous solution of ammonium nitrite decomposes when heated to give off nitrogen gas and water. This reaction can be used to prepare pure nitrogen gas. How many grams of ammonium nitrite must have reacted if 3.75 liters of nitrogen gas was collected over water at 25˚C ...
*October 20, 2014*

**chemistry**

Can someone help me with Chemistry Homework Due Tomorrow, Its about the Electrolysis of Hydrochloric Acid Practical we did and I Have to write a summary and I dont get what we did Y10 GCSE Higher Tier
*October 20, 2014*

**Chemistry**

The speed of light in a vacuum is 2.998 x 10^8 m/s. What is the speed of light in miles per hour? (1 km = 06214 miles)
*October 14, 2014*

**Physics**

The hare and the tortoise are at the starting line together. When the gun goes off, the hare moves off at a constant speed of 10 meters per second. (Ignore the acceleration required to get the animal to this speed.) The tortoise starts from a dead stop, but accelerates at a ...
*October 2, 2014*

**Physics**

A train is moving parallel and adjacent to a highway with a constant speed of 22 m/s. Ini- tially a car is 35 m behind the train, traveling in the same direction as the train at 36 m/s and accelerating at 4 m/s2. What is the speed of the car just as it passes the train? Answer...
*October 2, 2014*

**physics**

Due to continental drift, the North American and European continents are drifting apart at an average speed of about 3 cm per year. At this speed, how long (in years) will it take for them to drift apart by another 658.1 m?
*September 7, 2014*

**science**

from its name macro- means a large amount of substances or nutrients required for living organisms. Let me know if my answer helped you.
*September 6, 2014*

**P.E**

The answer for your question is heredity.
*September 5, 2014*

**math**

the mass of one red marble is 16g and you have 21 red marbles, therefore 16.21=336grams And you have 18 blue marbles and the mass of one blue marble is 20 grams therefore, 20.18=360g 336g+360g=696grams total in the box.. I hope my answer is correct.
*September 5, 2014*

**ALGEBRA**

for your second expression, you need to find 2 numbers that if you add or subtract will give you the middle term and if you multiply them, it will give you the last term. so going back to your example, the two number that if you multiply and they will give you (-14)is -7 and +...
*September 5, 2014*

**economics**

1) Give an example that you believe demonstrates when the cost of government actions outweighs the benefits.Identify the factors that may cause the costs of government actions to outweigh the benefits. I'm confused what does that mean? Thank you for your help!
*July 23, 2014*

**algebra**

The ratio of the lengths of strings that play the notes D and B (on a guitar), is 27 to 16. If a string 64 cm long plays B, what is the length of the string that plays a D?
*June 12, 2014*

**math**

The manager of a tea shop mixes two types of teas to make a specialty blend. Alone, the teas sell for $3.99 and $8.99 per ounce. How many ounces of each type of tea should be used to make 32 ounces of a mixture that sells for $5.99 per ounce?
*May 28, 2014*

**physics**

A steel (\alpha = 12 x 10^{-6} ^o C^{-1}) container with a volume of 548 {cm}^3 is filled with oil (\beta = 0.7 x 10^{-3} ^oC^{-1}). If the temperature is increased by 10^oC how much oil overflows? V_{spillage} =
*April 28, 2014*

**physics**

What is the total internal kinetic energy of 16.2 moles of a monatomic ideal gas at a temperature of 279 K? KE =
*April 28, 2014*

**physics**

A sound wave has a frequency of 1640 Hz. The air temperature is 46 degress F. What is the speed? v = What is the wavelenght of the sound? lambda =
*April 21, 2014*

**physics**

Water is in the big beaker in the figure on the left. Scale 1 reads 87 Newtons, scale 2 reads 544 newtons, and scale 3 reads 0 newtons. The hanging block has a density of 15 x 10^3 kg/m^3. What does scale 1 read after the block is fully lowered into the beaker of water? Scale...
*April 7, 2014*

**Physics**

Two objects with masses represented by m1 and m2 are moving such that their combined total momentum has a magnitude of 16.3 kg · m/s and points in a direction 71.5° above the positive x-axis. Object m1 is moving in the x direction with a speed of v1 = 2.84 m/s and ...
*March 2, 2014*

**math**

Sighting the top of a building, a surveyor measured the angle of elevation to be 60°. The measurement is taken 200 feet from the building. Find the building’s height. Express your answer in terms of feet and then round to two decimal places
*February 23, 2014*

**PHYSICS**

5. What is the maximum acceleration a car can undergo if the coefficient of static friction between the tires and the ground is 0.24? acceleration max=
*February 23, 2014*

**physics**

A -kg block is initially at rest on a frictionless horizontal surface. It is pulled with a constant horizontal force N. How long must it be pulled before its speed is m/s? t_{pull} =
*February 21, 2014*

**physics**

A block with a mass of 126 kg is pulled with a horizontal fource of F_{applied} across a rough floor. The coefficent of friction between the floor and the block is 0.7. If the block is moving at a constant velocity, what is the magnitude of F_{applied}? F_{applied} =
*February 21, 2014*

**physics**

Three blocks on a frictionless horizontal surface are in contact with each other. A force F is applied to block A and the blocks start to slide to the right of their initial position. Determine the acceleration of the system, if m_A = 12 kg, m_B = 38 kg, m_C = 4700 g, and F = ...
*February 21, 2014*

**Physics**

A physics book slides off a horizontal table top with a speed of 1.30 m/s . It strikes the floor after a time of 0.380s . Ignore air resistance. Find the height of the table top above the floor. Find the horizontal distance from the edge of the table to the point where the ...
*February 16, 2014*

**physics**

You are holding the neck of a champagne bottle at an elevation of 27 degrees when you pop the cork. The highest point in the cork's flight is 3.5 m above its initial height. What was the cork's initial speed? Use SI units in the second box.
*February 15, 2014*

**math**

The perimeter of a rectangular field is 300 meters. This field is to be fenced along three sides only. The fencing along its two lengths and one width is to be done at $50 per meter. If the total cost of fencing is $12,000, what are the field’s dimensions
*February 11, 2014*

**physics**

20.28792744 m/s thanks for nothing i solved it myself
*February 7, 2014*

**physics**

A ball is thrown straight upward from ground level. At what speed must the ball be thrown if it is to reach a maximum height 21 meters above the ground?
*February 7, 2014*

**Physics**

A 1500-kg car moving north at 27.0 m/s is struck by a 2165-kg car moving east at 13.0 m/s. The cars are stuck together. How fast and in what direction do they move immediately after the collision? 1. Degree north of east? 2. M/S?
*February 3, 2014*

**programming(visual basic)**

debugging exercise: Private Sub btnItemNumber_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnItemNumber.Click Dim decCost As Decimal Dim intCount As Decimal decCost = Convert.ToDecimal(txtCost.Text) Inventory(decCost, intCount) End Sub Private Sub...
*January 8, 2014*

**Math**

Select the x-coordinate of the vertex of the parabola defined by the function f(x) = -3x2 + 5x + 8.
*December 8, 2013*

**Statistics**

Determine the Null and Alternative Hypothesis for the following: A.) A company manufactures flares, they select 100 at random to determine if the flares last at least 3 hours on average. B.) A consumer group believes that a new sports coupe gets significantly less MPG than ...
*September 20, 2013*

**math**

The launch site for trigon balloon co. is 250 ft above sea level. A hot air balloon is launched from the site and begins to rise at a rate of 110 ft/min. At the same time, another balloon 2200 ft above sea level begins to descend at a rate of 150 ft/min. A. How long will it be...
*September 12, 2013*

**Physics**

If two protons and two neutrons are removed from the nucleus of an oxygen-16 atom, a nucleus of which element remains? Carbon 12 will be the answer, but i need to understand the answer. I requested help from a friend but was given the answer and not explained. I am having a ...
*August 28, 2013*

**chemistry**

A sample of naphthalene (C10H8) that has a mass of 0.7200 g is burned in a bomb calorimeter. The mass of the calorimeter is 1.580 kg, and its specific heat is 2.55 J/(g °C). As a result of the reaction, the temperature of the calorimeter increases from 22.00°C to 29.3&...
*August 22, 2013*

**chemistry**

The molar heat of fusion for water is 6.01 kJ/mol. How much energy must be added to a 75.0-g block of ice at 0°C to change it to 75.0 g of liquid water at 0°C? 1.44 kJ 10.18 kJ 12.48 kJ 25.04 kJ
*August 21, 2013*

**Math/Statistics**

A statistics teacher believes that the final exam grade for her elementary stats class have a normal distribution with a mean of 82 and a standard deviation on 8. Find the score which separates the top 10% of the scores from the lowest 90% of the scores.
*August 11, 2013*

**Algebra 1**

9 less than the product of 7 squared and a number is 6
*August 3, 2013*

**Math**

Kylee bought a pack of 12 cookies. Two thirds of the cookies are peanut butter. How many cookies in the pack are peanut butter?
*May 18, 2013*

**trig identities**

Find the exact value of cos (2theta) given csc theta = 8/3 and 0 < theta < pi/2
*May 8, 2013*

**mechanical/eginineering**

when a compound gear cluster is created how is the mechanical advantage calculated
*April 29, 2013*

**college physics**

how long would it take a 4.50kW MOTOR TO RAISE A 175KG BOILER TO A PLATFORM 15.0M ABOVE THE FLOOR?
*April 22, 2013*

**college physics**

How many seconds would it take a 7.00hp motor to raise a 475 lb boiler to a platform 38.0 ft high?
*April 22, 2013*

**Calculus**

Use logarithmic differentiation to find the derivative of the following: y=x^x^2 x>0 Please show all steps so I can following for future understanding
*April 21, 2013*

**Calculus**

Use logarithmic differentiation to find the following derivative y=(x+6)^4/(x-5)^6. Please show all steps so I can follow for future understanding. Thanks.
*April 21, 2013*

**Calculus**

Find the derivative of the following: f(x)=ln(e^(2x)/(x^2-4)^3 Please show all steps so I can follow Thanks!
*April 21, 2013*

**Calculus**

Use logarithmic differentiation to find derivative of y=x^x^2 x > 0. Please show all steps so I can follow the steps. Thank you.!
*April 20, 2013*

**ELECTROLYSIS OF ZnI2**

ELECTROLYSIS OF ZnI2 if you have done this experiment Please help me answer these questions as i missed the last half of my chem lab today. 1. What color change occurred when the wire is first heated. -next question is... What is the identity of the liberated metal? 2. what ...
*April 18, 2013*

**chemistry**

Hey guys please help me answer these chemistry questions.? 1. can a strong acid be diluted. explain in detail 2. can a weak acid be diluted. explain in detail 3. how does your observation of sunlight change when you place two different concentrations of food colored solution ...
*April 18, 2013*

**chemistry**

Hey guys please help me answer these chemistry questions.? 1. can a strong acid be diluted. explain in detail 2. can a weak acid be diluted. explain in detail 3. how does your observation of sunlight change when you place two different concentrations of food colored solution ...
*April 18, 2013*

**Physics**

1. You have a large wind tunnel of cross-sectional area 0.61[m2]. The wind speed is 4[ms-1]. Assume air density is 1 [kgm-3]. The Drag is 2.3[N]. What is the coeffecient of drag for the shape that has diameter 7.32[cm]? . Use three sig. figs. or N/A if there is not enough ...
*April 7, 2013*

**Physics**

What is the coeffecient of drag for the shape that has diameter 7.32[cm]? . Use three sig. figs. or N/A if there is not enough information. 2. You have a large wind tunnel of cross-sectional area 0.95[m2]. You have a set of shapes that are all the same shape except they each ...
*April 7, 2013*

**Chemistry**

What effect on the molar mass of the unknown acid would each of the following have-that is-would it make the calculated molar mass high, low, or would it have no effect? 1. Adding 5 drops of phenolphthalein instead of 1 drop. 2. Using a standard NaOH solution that has been ...
*April 3, 2013*

**Chemistry 111**

a) Write Bronsted acid-base equilibrium equations for the following: b) Show the acid-base conjugated species, labeling all species (1) HSO4- + C2O4-2 (2) HPO4-2 + NH4+
*April 2, 2013*

**Chemistry 111**

Write the conjugate base for each of the following: a. HPO4^-2 ____________________ b. H2O ____________________
*April 2, 2013*

**Chemistry 111**

Write the conjugate acid for each of the following: a. HCO3^1- ____________________ b. H2O ____________________
*April 2, 2013*

**chemistry**

A 23.4 mL sample of 0.300 M trimethylamine, (CH3)3N, is titrated with 0.399 M perchloric acid. After adding 6.67 mL of perchloric acid, the pH is
*April 1, 2013*

**Chemistry**

H2C2O4.2H2O(s) is primary standard substance. 2.3688g of oxalic acid hydrate were completely neutralized by 42.56ml of NaOH solution. Calculate the molar concentration of the NaOH solution. Write the balanced equation for the reaction.
*April 1, 2013*

**Chemistry**

What is the boiling point of a 25.20% (m/v) KNO3 solution ? (Kf of water = 1.86 0C/molal) (Kb of water = .52 0C/molal) (molar mass potassium nitrate = 101.10324 g/mole) The density of the solution is 1.09 g/ml What is the molarity of the solution? What is the molality of the ...
*March 31, 2013*

**Chemistry**

An aqueous solution containing 10.50 g of a compound in 100.0 ml of solution has an osmotic pressure of 0.0187 atm. at 25°C. What is the molecular weight of the compound?
*March 31, 2013*

**Chemistry**

Determine the value of the equilibrium constant,Kgoal , for the reaction N2(g)+O2(g)+H2(g)<=> (1/2)N2H4(g) + NO2(g) Kgoal=? by making use of the following information: 1.N2(g)+O2(g)<=>2NO(g), K1=4.1010x10^-31 2.N2(g)+2H2(g)<=>N2H4(g), K2=7.40x10^-26 3.2NO(g)+...
*March 31, 2013*

**physics**

1. Air flowing through a vent pipe of cross-sectional area 21[m^2] is traveling 0.89[ms^-1]. What is the flowrate? [18.7 m3s-1] Answer with three significant figures (don't forget to round!) or N/A if there is not enough information to answer the question. 2. Before the ...
*March 22, 2013*

**math**

If I plant a 7 foot tall tree. The height (h) of the tree, in feet, after n years is given by the equation h + 4n + 7. In how many years will the height be 39 feet?
*March 21, 2013*

**Thermochemistry**

Thanks!
*March 19, 2013*

**Thermochemistry**

My question is more conceptual. It is expressed in a series of two problems: What energy change occurs when 1.2 moles of methane combust with an enthalpppy change of -434 KJ? CH4+2O2 TO CO2+2H20 I understand it is simply the moles of mthane times the enthalpy change yet I am ...
*March 19, 2013*

**Physiology**

When maternal oxygen is transferred to the fetus and fetal CO2 is passed back, how does this affect the maternal dissociation curve? Does this shift increase the transfer of oxygen to the fetus?
*March 3, 2013*

**squared **

15.68 squared
*March 2, 2013*

**Chemistry**

find the molarity of 150. g H2SO4 solute dissolved into 900. g H2O solvent
*February 17, 2013*

**MATH**

a rectangular garden 9ft by 12 ft includes a uniform border of wood chips around a rectangular bed of flowers. If flowers take up half the garden's area. find the perimeter of the flower bed
*February 16, 2013*

**chemistry**

what determines the color of light when an electron moves from one level to another
*February 13, 2013*

**math 5th**

The new playground at Middledale school will be enclosed by a fence. The playground will be rectangular and will have an area of 225 sq. yd. The number of yards on each side will be a whole number. What is the least amount of fencing that could be required to enclose the ...
*February 12, 2013*

**math 5th**

Cristina has 16 square feet of material to make a rectangular quilt. She wants the quilt to have the least possible(minimum) perimeter. If Cristina uses all 16 square feet, what dimensions should she use for the quilt?
*February 12, 2013*

**math**

lara and maria finished 3/4 of their homework assignment. lara did 1/4 more of the assignment than maria. what fraction of the assignment did each girl finish?
*February 6, 2013*

**Geometry and Measurement**

blah blah
*February 6, 2013*

**Chemistry**

A gas occupies a volume of 502 cm3 at 20.0 C. What will be its volume at 106 C? I understand that it follows Charles' Law where the correct equation is V1/T1=V2/T2. My teacher expects all units of volume to be converted to Liters and all temperature to Kelvins. Using ...
*February 2, 2013*

**Calc**

A car is moving at 40 mi/h along a straight line when the driver sees a light turn red. She hits the brakes when she is 100 ft from the light and decelerates at the rate of 16 ft per second squared. How far does she travel before stopping? Choose the whole number that is ...
*January 20, 2013*

**Physics**

A wave described by y(x,t)=Asin(kx-wt) moves down a string. What is the maximum transverse speed an atom of the string can have? What is the displacement of this atom at this time?
*January 18, 2013*

**Physics**

A horizontal wire is held taut by a mass M hanging from its end over a pulley. A harmonic wave of wavelength is produced on the wire by a 52 Hertz vibration. If the mass of the density of the wire is 8.0 x 10^-3 kg/m, what is M?
*January 18, 2013*

**Physics**

The period of longitudinal sinusoidal wave is 0.16 seconds and its wavelength is 8.0 meters. Calculate the wave's speed, frequency, angular frequency and wave number.
*January 18, 2013*

**Physics**

Two copper wires are held under the same tension. If the linear density of the second is twice that of the first, what is the speed of the waves on the second wire (relative to the first)?
*January 18, 2013*

**chemistry 122**

81) According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy? Assume excess SiO2. SiO2(s) + 4 HF(g) �� SiF4(g) + 2 H2O(l) DH°rxn = -184 kJ 81) A) 173 g B) 37.5 g C) 150. g D) 107 g E) 42.7 g
*December 11, 2012*

**Math**

Jose said all of the multiples fo 8 are also multiple of 2. Jamila said that all of the multiple of 8 are also multiples of 4 . Who is correct
*November 28, 2012*

**algebra**

-12a+3(2a+1)=-6a
*November 8, 2012*

**Chemistry**

When 22.7mL of o.500 M H2SO4 is added to 22.7mL of 1.00 M KOH in a coffee-cup calorimeter at 23.50 degrees Celsius, the temperature rises to 30.17 degrees Celsius. Calculate the delta h of this reaction. (Assume that the total volume is the sum of individual volumes and that ...
*October 19, 2012*

**math**

I need to know how to write a word expression for 535 divided by 21
*October 11, 2012*

**math**

which alphabet letters are concave polygons
*October 3, 2012*

**math**

bibay has 48 pieces of mangoes, jabby has 32 pieces, and kyla has 64 pieces. they want to put it in baskets with the same number of mangoes in each basket. what is the most number of mangoes that they can put in each basket?
*October 3, 2012*

**math**

a red light winks every 6 seconds, a white one every 10 seconds, and a green one every 14 seconds. how often they wink together?
*October 3, 2012*

**math**

arnie has between 300 and 400 stickers in her collection. when she divided them into groups of 4, 5, or 9, there is always one sticker left over. how many stickers does arnie's collection contain?
*October 3, 2012*

**Math**

A surface ship is moving in a straight line (horizontally) at 8km/hr. At the same time, an enemy submarine maintains a position directly below the ship while driving at an angle that is 20 degrees below the horizontal. How fast is the submarines altitude decreasing?
*September 29, 2012*

**physics**

Two people pull as hard as they can on ropes attached to a 200 kg boat. If they pull in the same direction, the boat has an acceleration of 1.44 m/s2 to the right. If they pull in opposite directions, the boat has an acceleration of 0.518 m/s2 to the left. What is the force ...
*September 25, 2012*

**reading**

what does inference character mean
*September 22, 2012*

**physics**

A woman at an airport is towing her 17.0 kg suitcase at constant speed by pulling on the strap at an angle θ above the horizontal. She pulls on the strap with a 26.0 N force, and the friction force on the suitcase is 14.0 N.
*September 21, 2012*

**math**

in a class one quarter of students have blonde hair and brown eyes and one third have brown eyes and blonde hair what fraction of the class in total have brown eyes
*September 19, 2012*

**Geography**

Is this correct? What line of longitude forms the other half of the prime meridian? When joined with the Prime Meridian the 180 degree of longitude forms a complete circle
*September 14, 2012*

**math**

2(10)+1(3)=23 money spent 2(4)+1(x)=23 x= 15 oranges
*September 2, 2012*

**chemistry**

At 25 degrees celsius, what is the mass in grams of 2.5L of mercury?
*September 2, 2012*

**Hypothesis - Statistics**

At one high school, the average amount of time tenth-graders spend watching television each week is The principal introduces a campaign to encourage the students to watch less television. One year later, the principal wants to perform a hypothesis test to determine whether the...
*July 28, 2012*

**chemistry**

Four solution are prepared and mixed together: Start with 100.0ml of 0.100M BaCl2. Add 50.0ml of 0.100M AgNO3. Add 50.0ml of 0.100M H2So4. Add 250.0ml of 0.100M NH4. Write an equation for any reaction that occurs after each step and calculate the concentration of Ba,CL,NO3,NH4...
*May 2, 2012*

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