# Sara

Popular questions and responses by Sara-
## statistics

the probability that a house in an urban area will develop a leak is 5%. if 23 houses are randomly selected, what is the probability that none of the houses will develop a leak?

*asked on April 28, 2013* -
## math

Two cars are side by side. One is 3.9 meters long. The other is 6% shorter. How long is the second car? I know the answer is 3.7, but how?

*asked on June 25, 2018* -
## math

Find dy/dx and d2y/dx2. x = et, y = te−t

*asked on July 28, 2014* -
## Chemistry

The compound M2X3 has a molar solubility of 0.0190 M. What is the value of Ksp for M2X3? Here are the choices: 1. 3.52 × 10^-6 2. 4.12 × 10^-5 3. 8.91 × 10^-8 4. 2.48 × 10^-9 5. 2.67 × 10^-7

*asked on April 27, 2014* -
## chemistry

When the conductivity is at a minimum, what must be true about the amount of Ba(OH)2 compared to H2SO4? The Ba(OH)2 dissociates as Ba+2 + 2 OH-. H2SO4 dissociates as 2 H+ + SO4-2. Why does it not conduct at this low point? Why does it conduct more before

*asked on July 25, 2012* -
## math

When 300 apple trees are planted per acre, the annual yield is 1.6 bushels of apples per tree. For every 10 additional apple trees planted, the yield reduces by 0.01 bushel per ten trees. How many apple trees should be planted to maximize the annual yield?

*asked on April 11, 2020* -
## business math

Jen purchased a condo in Naples Florida for $699,000. She put 20% down and financed the rest at 5% for 35years. What are Jens total finance charge?

*asked on April 12, 2015* -
## Geometry

30. PLis the angle bisector of KPM.Which can you conclude from this statement? You also can see this question number 30 on this website.Please add hyperlink. micahshue.weebly.com/uploads/2/2/5/6/22568286/final_exam_review.pdf How answer is A and i want

*asked on July 31, 2020* -
## Chemistry

Calculate the molarity and the molality of an NH3 solution made up of 30 g of NH3 in 70 g of water. The density of the solution is 0.982 g/ml. Molar Mass of NH3 = 17.04 g

*asked on December 2, 2010* -
## Geometry

Based on the information in the diagram, can you prove that the figure is a parallelogram? Explain. a. Yes; opposite sides are congruent. b. Yes; opposite angles are congruent. c. No; you cannot prove that the quadrilateral is a parallelogram. d. Yes; two

*asked on July 21, 2020* -
## Geometry

YZ = √ 5 and XZ = √ 2. Find XY. Answer in simplified radical form. It's a right triangle, Y vertex is 90 degree. plz help.

*asked on July 15, 2020* -
## English

Read the passage. Zeke and Petra went to the horse show over the weekend, they said they saw Arabians and other breeds performing in the show ring. Which answer correctly explains what is incorrect about the passage? A. A comma splice is used to connect

*asked on May 12, 2020* -
## math (solid mensuration)

A light is placed 5 ft. from the center of a globe 3 ft. in diameter. Find the area of the illuminated portion. thank you!

*asked on May 7, 2012* -
## math

I am A number in the Last row on the hundreds chart. my ones digit is even.the differance between the ones digit and tens digit is 5.What number am i?

*asked on September 28, 2010* -
## Geometry

YZ = √ 5 and XZ = √ 2. Find XY. Answer in simplified radical form. in the given triangle picture Y vertex is 90 degree. plz help.

*asked on July 14, 2020* -
## linear algebra

Let T be the plane 2x−3y = −2. Find the shortest distance d from the point P0=(−1, −2, 1) to T, and the point Q in T that is closest to P0. Use the square root symbol '√' where needed to give an exact value for your answer. I need help with this

*asked on October 2, 2018* -
## chemistry

Based upon the intermolecular forces present, rank the following substances according to the expected boiling point for the substance: MgF2, H2O, HCl, N2

*asked on April 3, 2014* -
## Geometry

The diagonals of an isosceles trapezoid divided it into one pair of congruent triangles and one pair of similar triangles.

*asked on July 25, 2012* -
## Mendelian Genetics

Assume you are performing a cross between a plant that is heterozygous for the dominant traits red flowers and wrinkled seeds, with a plant that is homozygous for the recessive traits white flowers and smooth seeds. Assume the alleles are R for red

*asked on January 20, 2015* -
## How many milliliters of a stock solution of 6.00 M

How many milliliters of a stock solution of 6.00 M HNO3 would you have to use to prepare 0.190 L of 0.490 M HNO3? I used the equation M1V1=M2V2 6M*V1 = 0.190L*0.490 M lead me to this V1=0.190L*0.490M/6.00 M =0.0931 L per M/6.00M =0.0155166L

*asked on August 28, 2015* -
## science

You know that a collision must be "elastic" if: The momentum of the two-object system doesn't change The sum of the final kinetic energies equals the sum of the initial kinetic energies There is no change in the internal energies of the objects (thermal

*asked on July 24, 2014* -
## math

The value of Sara's new car decreases at a rate of 8% each year. 1.Write an exponential function to model the decrease in the car's value each month. 2.Write an exponential function to model the decrease in the car's value each week. 3.Write an exponential

*asked on November 17, 2017* -
## Chemistry

From the equation below, how many grams of barium sulfate can be produced from 20.8 g of barium chloride? BaCl2 + Na2SO4 -> BaSO4 + 2NaCl

*asked on May 19, 2015* -
## U.S. History

which of the following was not a weakness of the articles of confederation (1781-1789)? A) a week "league of friendship" among the states B) the requirement of unanimous approval by all 13 states for amendments C) no judicial branch D) no congressional

*asked on November 24, 2014* -
## Chemistry

Given the thermodynamic data in the table below, calculate the equilibrium constant for the reaction: 2SO2(g)+O2--> 2SO3 Substance (DeltaH^o) (Delat S^o) SO2 -297 249 O2 0 205 SO3 -395 256 Answer (it was given) 2.32x10^24 Even though the answer is given

*asked on March 16, 2008* -
## math

How many gram ofsodiun fluoride should be added to 100000liter of drinking water containing 0.6 ppm of sodium fluoride to provide a recommended concentration of 1.75 ppm

*asked on June 23, 2014* -
## DrBobb222 : Chemistry HElp...Please Check

Standardization of the Sodium Thiosulfate Solution Make up a standard solution of potassium iodate by accurately “weighing by difference” about 0.1 g of KIO3 and placing it in your 100 mL volumetric flask. Fill the flask to mark with distilled water.

*asked on October 21, 2008* -
## Chemistry

Elemental sulfur can be converted to sulfur dioxide by combustion in air. Sulfur dioxide will react with water to form sulfurous acid (see balanced equation below). SO2(g) + H2O(l) → H2SO3(l) What mass of sulfur dioxide is needed to prepare 29.36 g of

*asked on April 23, 2019* -
## math

The formula of a trapezoid is A=1/2h(b1+b2) Express b1 in terms of A,h,and b2 I did A=1/2hb1+1/2hb2 A=hb1/2 +hb2/2 A-hb2(2/h)=hb1/2(2/h) A-b2=b1 I am not sure if this is correct? I was confused on how to do this. Any help or explanation is greatly

*asked on October 4, 2016* -
## chemistry 30a

What volume (in mL) of an 8% w/v acetic acid solution would be needed to form 2.2 L of carbon dioxide gas at 25.2 degrees Celsius and 0.9982 atm? Assume the acid is reacted with excess sodium bicarbonate, and round your final answer to two sig figs.

*asked on March 12, 2012* -
## Science

Which of the following is a characteristic of nonmetals? Nonmetals are often brittle solids. Nonmetals are often malleable. Nonmetals often conduct electricity. Nonmetals are often ductile.

*asked on November 17, 2015* -
## Advanced Functions

he value of a new car depreciates at a rate of 12% per year. Write an equation to represent the approximate value of a car purchased for $23 000. Determine the value of the car two years after it is purchased. Approximately how many years will it take

*asked on January 12, 2011* -
## Math

Jason was hired to mow a lawn that covers an area of 2 3/4 acres it took him 4 1/8 hours to complete the job what was his unit rate and hours per acre you multiply the numerator and a complex fraction by the reciprocal of the denominator to calculate our

*asked on February 7, 2018* -
## business math

Andres Michael bought a new boat. He took out a loan for $23,980 at 3.75% interest for 4 years. He made a $4,470 partial payment at 4 months and another partial payment of $3,180 at 9 months. How much is due at maturity?

*asked on October 10, 2014* -
## Physics

Multiple Concept Example 9 provides background pertinent to this problem. The magnitudes of the four displacement vectors shown in the drawing are A = 16.0 m, B = 12.0 m, C = 13.0 m, and D = 23.0 m. Determine the (a) magnitude and (b) direction for the

*asked on May 29, 2012* -
## finance

Assume that the export price of a Nissan XTerra from Osaka, Japan is ¥3,750,000. The exchange rate is ¥121.84/$. The forecast rate of inflation in the United States is 2.8% per year and is 0.6% in Japan. a. What is the export price of the XTerra at the

*asked on May 5, 2011* -
## chem

How many moles of O are in 13.0 mol Fe(NO3)3? can you please find this using dymensional analysis and show me how you worked it? Thans

*asked on November 10, 2010* -
## Socials

How did Napoleon help to spread feelings of nationalism throughout Europe? Explain why you think nationalism is a positive or negative force, or both. Napoleon helped to spread feelings of nationalism throughout Europe by initially using it to help him

*asked on November 9, 2009* -
## chemistry

Using your answer from Part A, calculate the volume of a mole of Na atoms (in cm3/mol ). Assume that the entire volume is occupied by Na atoms leaving no gaps or holes between adjacent atoms. (Answer A is V= 2.70*10^7)

*asked on November 10, 2008* -
## Maths

A boy spends 1/4 of his money on sweets and 1/3 on computer games. What fraction of his money does he not spend?

*asked on April 11, 2017* -
## Chemistry

CoCl2CO+Cl2 Keq=7.6*10^-4 M CoCl2 is introduced in a closed container until its concentration is .890 M. What will be the concentration of Cl2 once the reaction has reached equilibrium?

*asked on July 20, 2013* -
## Calculus

Calculate the height of a cylinder of maximum volume that can be cut from a cone of height 20 cm and base radius 80 cm , please help me

*asked on December 25, 2011* -
## science

how does a magnitude-8.0 earthquake could be classified as a low-intensity earthquake? LAST SCIENCE QUESTION!

*asked on April 1, 2009* -
## math

The height of a frustum of a pyramid is 12 and the areas of its bases are 9 and 25. What is the volume of the frustum?

*asked on March 22, 2020* -
## Math

Marie forgot the formula for finding the area of a circle, so she divided the circle into sectors and created a parallelogram-shaped figure. What should she use as the height of the figure? A.the radius B.360 C.12 of the circumference D.the circumference

*asked on February 21, 2020* -
## Math

Form the perfect square trinomial in the process of completing the square. What is the value of c? x^2 + 3x + c = 7/4 + c c =

*asked on May 22, 2016* -
## chemestry

consider the reaction 2N2O(g) == O2(g)+2N2(g).which of the following will cause a shift in the equilibrium to the left?

*asked on November 1, 2014* -
## Chemistry

The complex [Co(ox)3]4- has a high-spin electron configuration. How many unpaired electrons are there in the complex? I know because it's a high-spin, it's tetrahydral shaped. But I don't know what (ox) is so, I'm stuck in finding the oxidation state of Co

*asked on July 26, 2013* -
## Chemistry

Calculate how much acetylene (C2H2) can be produced from 358 g of H20 and an excess of CaC2 if the perfect yield for this reaction is 94.5% CaC2+H2)-> C2H2+C2H2+CA(OH)2

*asked on July 20, 2013* -
## Chemistry

Dinitrogen pentoxide, N2O5, decomposes by first-order kinetics with a rate constant of 0.15 s-1 at 353 K. (a) What is the half-life (in seconds) for the decomposition of N2O5 at 353 K? (b) If [N2O5]0 = 0.0579 mol·L-1, what will be the concentration of

*asked on June 28, 2013* -
## Calculus - HELP plz!

Find all of the first partial derivatives of f(x,y,z)=arctan y/xz

*asked on June 2, 2013* -
## Chemistry

How much of NaOH (in grams) is needed to prepare 546 mL of solution with a pH of 10.00 ?

*asked on February 16, 2011* -
## chem

Which of the following elements would you expect to gain electrons in chemical changes? (Select all that apply.) gold chromium zirconium nitrogen iodine

*asked on September 21, 2010* -
## MACROECONOMICS

Which of the problems in the construction of the CPI might be illustrated by each of the following situations? Explain. a. the invention of the Sony Walkman b. the introduction of air bags in cars c. increased personal computer purchases in response to a

*asked on April 12, 2009* -
## Algebra

The lesser of two consecutive even integers is 10 more than one-half the greater. Find the integers.

*asked on October 1, 2007* -
## statistics

The professor teaching a large introductory class gives a final exam that has alternate forms, A, B, and C. A student taking the exam using Form B is upset because she claims that Form B is much harder than Forms A and C. Discuss how percentile point data

*asked on April 22, 2017* -
## Physics

A flywheel turns through 60 rev as it slows from an angular speed of 2.8 rad/s to a stop. How much time is required for it to complete the first 30 of the 60 revolutions?

*asked on March 6, 2017* -
## Chemistry

Sulfur dioxide reacts with chlorine to produce thionyl chloride and dichlorine oxide S: 32.0 amu O: 16.0 amu Cl: 35.45 amu SO2 + 2Cl2 --> SOCl2 + Cl2O If 0.400 moles of chlorine gas reacts excess sulfur dioxide, how many moles of dichlorine oxide are

*asked on May 1, 2015* -
## science

A car of mass 2900 kg collides with a truck of mass 4800 kg, and just after the collision the car and truck slide along, stuck together. The car's velocity just before the collision was < 34, 0, 0 > m/s, and the truck's velocity just before the collision

*asked on June 25, 2014* -
## econ

The terms below are measures or individual components of the money supply. Specifically considering the money supply of the United States, rank these items from largest to smallest in terms of dollar value. Currency, M2,M1,Balances in savings accounts,

*asked on March 27, 2014* -
## Chemistry

A sample of oxygen is collected over water at 22 C and 762 torr. What is the partial pressure of the dry oxygen? The vapor pressure of water at 22C is 19.8 torr.

*asked on July 20, 2013* -
## Statistics

Solve the following problems by using the binomial formula. a. If n = 4 and p = .10 , find P(x = 3) . b. If n = 7 and p = .80 , find P(x = 4) . c. If n = 10 and p = .60 , find P(x ¡Ý 7) . d. If n = 12 and p = .45 , find P(5 ¡Ü x ¡Ü 7) .

*asked on July 29, 2011* -
## chemistry

In the reaction between CV+ and –OH, one species is acting as the Lewis base, the other as the Lewis acid. (Note: A Lewis acid is not necessarily a proton donor. It is, however, always an electron pair acceptor). Which reagent is the Lewis acid? A. CV+

*asked on July 13, 2010* -
## math

A regular triangular pyramid has slant height 6 cm and base edges of length 15 cm. Find the volume of the pyramid and the surface area.

*asked on February 27, 2020* -
## Science

When hair is combed with a hard rubber comb, the hair becomes positively charged because the comb A. Transfers protons to the hair B. Remove electrons from the hair C. Transfers electrons to the hair D. Remove both times from the hair I could be removed

*asked on February 11, 2016* -
## Chemistry

Which of the following elements is least likely to form a cation that will then form an ionic bond with an ion of a Group 7A element? S K Rb Fr

*asked on December 1, 2015* -
## Business Math

Andres Michael bought a new boat. He took out a loan for $23,980 at 3.75% interest for 4 years. He made a $4,470 partial payment at 4 months and another partial payment of $3,180 at 9 months. How much is due at maturity?

*asked on October 10, 2014* -
## Empires

I need help to compare and contrast the Babylonian and Hittite empires

*asked on September 22, 2014* -
## CALCULUS-plz help!

For the curve r = 2 sin 3(theta): Find the arc length of one petal

*asked on April 16, 2013* -
## Social Studies

The 1978 Supreme Court decision in Bakke v. Regents of the University of California A. ruled in favor of affirmative action within specified limits. B. established the "red state-blue state" divide. C. established the rights of students to appeal college

*asked on August 22, 2012* -
## Math

A science museum requires 3 adult chaperones for every 15 students on a field trip. How many chaperones would be needed for a group of 125 students?

*asked on March 24, 2011* -
## Chemistry

A solution of 2.50 g of a compound having the empirical formula C6H5P in 25.0 g of benzene(C6H6) is observed to freeze at 4.3 degrees C. Calculate the molar mass of the solute and its molecular formula.

*asked on December 3, 2010* -
## Math

Mary buys 8 widgets for $40.00. She adds $1.00 in enhancements to each widget and sells them for $9.00 each. What is Mary's estimated gross profit margin? 25% 33% 39% 44% 50% 67$

*asked on August 13, 2010* -
## Physics

A car is traveling along a straight road at a velocity of +31.0 m/s when its engine cuts out. For the next ten seconds, the car slows down further, and its average acceleration is a1. For the next five seconds, the car slows down further, and its average

*asked on November 30, 2008* -
## math

Find how many six-digit numbers can be formed from the digits 2, 3, 4, 5, 6 and 7 (with repetitions), if: the numbers formed must be divisible by 25

*asked on April 25, 2020* -
## Chemistry

Restart the PhET simulation and set it up in the following manner: select Oscillate, select No End, and use the parameters in parentheses by sliding the bars for Amplitude (1.00 cm), Frequency (1.20 Hz ), Damping (none), and tension (highest). Using the

*asked on October 18, 2018* -
## Please help

Which best describes Hitler's beliefs as expressed in Mein Kampf? Revolution was needed to create a classless society. Germany could control the world with the help of the Japanese. All races could live peacefully under German domination. Jewish people

*asked on May 13, 2015* -
## History

what are two themes that would be appropriate for thematic time lines of important events from prehistory to A.D.1600.

*asked on January 18, 2015* -
## calculus

A street light is mounted at the top of a 6-meter-tall pole. A man 2 m tall walks away from the pole with a speed of 1.4 m/s along a straight path. How fast is the tip of his shadow moving when he is 16 m from the pole?

*asked on October 16, 2012* -
## math

what is the largest negative coterminal angle of -417?

*asked on August 16, 2011* -
## CHemistry Help pleaseee

Imagine that you have a 6.00 L gas tank and a 3.00 L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 115 atm, to what

*asked on October 13, 2008* -
## physics

A car travels on a straight road for 40km at 30km/h. It then continues in same direction for 40km at 60km/h. a)What is the average velocity of the car during the 80km trip?(assume it moves in positive x direction) b)What is the average speed? c)graph and

*asked on September 10, 2006* -
## chemistry

For the following reaction at equilibrium in a closed vessel, ΔrH = −153 kJ per mol of CH3CHO. CH3CHO(g) ⇌ CH4(g) + CO(g) Which of the following statements are correct? a. For the thermodynamic equilibrium constant, K at 298 K is greater than K at 500

*asked on April 8, 2020* -
## math

A sphere of radius 3 is inscribed in a cylinder. What is the volume inside the cylinder but not inside the sphere?

*asked on March 5, 2020* -
## math

A regular square pyramid has a height of 2 and lateral edges of length 10. What is the lateral area and total surface area of the pyramid?

*asked on February 27, 2020* -
## Physics

I need help with this question with explanation. Thanks A particle of mass m starts from rest at position x = 0 and time t = 0. It moves along the positive x-axis under the influence of a single force Fx = bt, where b is a constant. The velocity v of the

*asked on December 19, 2019* -
## english 3

huck mentions that he wishes the widow douglas could know about his efforts to save the men on the wreck of the walter scott. pretend that you are huck and write a letter to the widow, explaining the situation and what you did about it. try to copy the

*asked on August 2, 2019* -
## physics

If 335 g of water at 65.5 °C loses 9750 J of heat, what is the final temperature of the water? Liquid water has a specific heat of 4.18 J/(g.°C). °C (Answer a number only, no units. Round to the tenth place). This is an example of an endothermic or

*asked on May 22, 2017* -
## algebra

Bob needs to wash the windows on his house. He has a 25-foot ladder and places the base of the ladder 10 feet from the wall on the house. How far up the wall will the ladder reach?

*asked on November 27, 2016* -
## Chemistry

In which of the following substances does sharing of electrons between two atoms occur? He Nal PO43– Ag

*asked on December 1, 2015* -
## Chemistry

When the following reaction took place at 23.8 and a pressure of 758 torr, 3.9 L of o2 were collected. What mass of KCIO3 decomposed? KCIO3->KCI+O2

*asked on July 20, 2013* -
## physics

Calculate the magnitude of the gravitational force between the Earth and an m = 6.00 kg mass on the surface of the Earth. The distance to the center of the Earth from the surface is 6.37×103 km and the mass of the Earth is 5.98×1024 kg. B)Calculate the

*asked on March 22, 2013* -
## chemistry help!!

The half-life for the process 238U 206Pb is 4.5 109 yr. A mineral sample contains 45.9 mg of 238U and 16.8 mg of 206Pb. What is the age of the mineral? i used the equation: n(T)=n(O)/2^(t/halflife) and i got 6.53e9 but it is wrong. what am i doing wrong?

*asked on September 5, 2012* -
## MATH

You wish to mentally estimate the total cost of items that have the following prices: $1.85, $.98, $3.49, $9.78, and $6.18. Rounding off the items to the nearest half-dollar, your estimate of the total cost of these items is A. $22.50. B. $22.30. C.

*asked on August 18, 2012* -
## Math

What words have a horizontal line of symmetry when printed horizontally, and a vertical line of symmetry when printed vertically. The only word I have is HI.

*asked on February 5, 2010* -
## calc

If 4x2+3x+xy=2 and y(2)=–10 , find y'(2) by implicit differentiation. i keep getting the wrong answer for this problem evn when plugging 2 in for y.

*asked on May 9, 2008* -
## chem

A 1.0 M solution of an unknown weak base has a pH of 12.3 at 25 oC. What is the identity of the base? a. Ammonia, pKb = 4.8 b. Aniline, pKb = 9.5 c. Methylamine, pKb = 3.4 d. Pyridine, pKb = 8.8

*asked on April 8, 2020* -
## Math

When a class took a math test, 15% of the class failed, 25% made some mistakes (but didn’t fail), and 24 students got perfect scores. How many students were in the class?

*asked on February 23, 2017* -
## Percentage

A flat-screen TV costs $1,400. The TV is on sale for 35% off. What's the discount price?

*asked on January 4, 2017* -
## physic

The position function x(t) of a particle moving along an x axis is x = 6.00 - 8.00t2, with x in meters and t in seconds. (a) At what time and (b) where does the particle (momentarily) stop? At what (c) negative time and (d) positive time does the particle

*asked on September 26, 2015*