# Alexandra

Popular questions and responses by Alexandra-
## ap chem

calculate the lattice enthalpy of potassium fluoride from the following data: enthalpy of formation of K(g): +89 kJ · mol−1 first ionization energy of K(g): +418 kJ · mol−1 enthalpy of formation of F(g): +79 kJ · mol−1 electron affinity of F(g):

*asked on July 13, 2010* -
## Chemistry Please help

A bottle of 12.0 M hydrochloric acid has only 35.7 mL left in it. What will the HCl concentration be if the solution is diluted to 250.0 mL?

*asked on September 29, 2013* -
## Geometry

You are planning to use a ceramic tile design in your new bathroom. The tiles are blue-and-white equilateral triangles. You decide to arrange the blue tiles in a hexagonal shape as shown. If the side of each tile measures 7 centimeters, what will be the

*asked on April 10, 2012* -
## chem

The reaction: 2C2H2+5O2->5O2->4CO2+2H2O is performed by mixing 175 grams of C2H2 and 175 grams of O2 to produce 127 grams of CO2 1)Limiting reagent 2)Theretical yeield of CO2 3)Percent yield of CO2

*asked on September 29, 2013* -
## Physical Science

C(s) + H2O(g) + Heat CO(g) + H2(g) 17. How would you adjust the temperature to increase the amount of product? 18. Does the removal of hydrogen gas as it is produced shift the reaction to the left or the right? My last two questions on my homework that I

*asked on October 11, 2013* -
## Physics

If the puck strikes the goalie's pads and stops in a distance of 4.14 cm, what average force is exerted on the pads? Answer in units of N. This is part three of three parts. 1st Part: A player strikes a hockey puck giving it a velocity of 39.486 m/s. The

*asked on November 25, 2012* -
## physics

An object of mass 5 kg is dropped from a certain height. Just before it strikes the ground it has a kinetic energy of 1250 J. From what height was the object dropped? Ignore air resistance and use g = 10 m/s2.

*asked on August 29, 2012* -
## AP Chemistry

If a saturated solution of Potassium Chlorate at 80 degrees celsius cools to room temperature (25 degrees celsius), how many grams of crystals form?

*asked on December 31, 2014* -
## Physics

A 10.2 kg weather rocket generates a thrust of 200N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 500N/m, is anchored to the ground. a) Initially before the engine is ignited,

*asked on November 25, 2010* -
## Chemistry

Write the formula of the corresponding acid that contains this anion. Express your answer as a chemical formula. The arsenite ion has the formula AsO33−.

*asked on February 21, 2017* -
## Chemistry

Xe(g) + F2(g) ----uv light---> Xe F2(s) XeF2(g) + 2F2(g) ---catalyst---> XeF6(s) XeF6(s) + H2O(l) ------> Xe O3(s) + 6HF(g) Looking at these three reactions respond the following: a) For each 0.0250 grams of xenon hexaflouride that reacts, what mass of

*asked on January 22, 2012* -
## scientist

Which is the best reason for the smaller number of drone bees compared to the number of worker bees in a beehive?

*asked on August 27, 2011* -
## Math/3rd grade

If you forget the product of 9 and 9, what can you do to figure it out?

*asked on January 13, 2011* -
## physics

When a 2.60-kg object is hung vertically on a certain light spring described by Hooke's law, the spring stretches 2.30 cm. (a) What is the force constant of the spring? (b) If the 2.60-kg object is removed, how far will the spring stretch if a 1.30-kg

*asked on April 21, 2010* -
## egypt

can any one please tell me info about egypt like about cario...... because i need tomake a leaflet about egypt please help me.....

*asked on September 27, 2007* -
## Mathematics

Find the midpoint of the line segment with end coordinates of: (−3,−1) and (−4,2) Give coordinates as decimals where appropriate.

*asked on June 16, 2020* -
## science

1.Carbon-14 is a radioactive isotope. What is an isotope? What is the approximate half-life of carbon-14?

*asked on October 21, 2019* -
## math

The data set below shows the number of players on each softball team in a tournament: 9 12 8 7 7 21 11 9 8 7 10 7 10 11 Which of the following statements is true based on the data set?

*asked on May 31, 2017* -
## Physics

A large pot is placed on a stove and 1.2 kg of water at 14°C is added to the pot. The temperature of the water is raised evenly to 100°C just before it starts to boil. (a) What amount of heat is absorbed by the water in reaching 100°C? (b) The water

*asked on October 27, 2014* -
## Physics

On Earth a fit astronaut without a space suit and life support pack can leap straight up and leave the ground with an initial vertical velocity of about v1y = 2.4 m/s and rise to a height of about h = 0.24 m above the point where he first loses contact

*asked on September 17, 2014* -
## Physics

A cannon is fired horizontally from atop a 40.0 m tower. The cannonball travels 180 m horizontally before it strikes the ground. With what velocity did the ball leave the muzzle? Okay so this is my work for this problem. please help If I did something

*asked on September 13, 2014* -
## Physics

Two girls decide to jump off a diving board. Katherine steps off the diving board. Anna runs straight off the diving board so that her initial velocity is solely horizontal. They both leave the diving board at the same time. Which one lands in the water

*asked on September 13, 2014* -
## Physical Science

24. What happens when a solution of nitric acid (HNO3) is added to a solution of potassium hydroxide (KOH)? What are the products? 25. Which of the following compounds can react with H2SO4 to form a salt: NaCl, Ca(OH)2, HF, AlCl3, H2O, Mg(OH)2? Name the

*asked on October 15, 2013* -
## chem

write the correct net ionic equation and identify spectator ions when CoSO4 and BaCL2 mix

*asked on September 29, 2013* -
## Algebra 1

The manager of a shopping mall was asked to rope off a rectangular section of the parking lot for an automobile show. The area roped off was 250 ft by 300 ft. Post were to be placed every 25 ft around the lot. How many posts were needed? The one question I

*asked on September 9, 2013* -
## calculus (gr 12)

Evaluate each of the following. Show all your calculations. a) f'(3) if f(x) = x^4 − 3x b) f' (−2) if f(x) = 2x^3 + 4x^2 − 5x + 8 c) f" (1) if f(X) = −3x^2 − 5x + 7 d)f" (−3) if f(x) = 4x^3 −

*asked on April 16, 2013* -
## calculus (gr 12)

Evaluate each of the following. Show all your calculations. a) f'(3) if f(x) = x^4 − 3x b) f' (−2) if f(x) = 2x^3 + 4x^2 − 5x + 8 c) f" (1) if f(X) = −3x^2 − 5x + 7 d)f" (−3) if f(x) = 4x^3 −

*asked on April 16, 2013* -
## calculus (gr 12)

Determine the velocity and acceleration as functions of time, t, for s(t) = 45t − 5t^2, where s(t) represents the distance as a function of time. (Hint: velocity and acceleration correspond to the first and second derivatives of the distance)

*asked on April 16, 2013* -
## calculus (gr 12)

The forward motion of a space shuttle, t seconds after touchdown, is described by s(t) = 189t − t^3 , where " is measured in metres. a) What is the velocity of the shuttle at touchdown? b) How much time is required for the shuttle to stop completely? c)

*asked on April 16, 2013* -
## calculus

Determine the maximum and minimum of each function on the given interval. a) = 2x^3 − 9x^2 ,−2 ≤ x ≤ 4 b) = 12x − x^3 , x∈ [−3,5]

*asked on April 15, 2013* -
## physics

A 20-N horizontal force pushes an object along a rough floor so that the object moves with a constant velocity of 7.0 m/s. How much power does this force deliver to the object?

*asked on August 29, 2012* -
## geometry

Point C is the center of the circle. Arc AB measures 5x + 2. Angle ACB measures 3x + 14. Find the value of x.

*asked on October 27, 2011* -
## Calculus

I don't understand how to answer this problem: The base of a solid is bounded by y=x+1 and y= x^2-1. Find the volume of the solid if the cross section is perpendicular to the x axis are equilateral triangles.

*asked on April 17, 2011* -
## Chemistry

If 10.0 grams of sodium bicarbonate reacts with 50.0mL of 2M acetic acid, what is the limiting reactant? what reactant is in excess, and by how much? What volume of carbon dioxide gas would form?

*asked on March 10, 2011* -
## Chemistryy

what mass of silver nitrate (AgNO3) is required to prepare 400 grams of a 3.50% solution of AgNO3? Options: 1. 0.00875 g 2. 114.28 g 3. 1400 g 4. 14 g

*asked on July 13, 2010* -
## US history

Which section of the country will be affected by the embargo of 1807?

*asked on December 15, 2019* -
## Math

Consider the quotient, f(x)/x-h What is the remainder of this quotient? My answer- f(x-h)

*asked on May 31, 2019* -
## English

1. What is the best summary of lines 1–16? (1 point) Alice cannot reach the doorknobs. Alice keeps shrinking until she is very tiny. She talks about being smaller than furniture in the room. She throws the Rabbit’s gloves and fan on the floor. When she

*asked on May 21, 2019* -
## Financial math

A couple wants to lend money using the house value as a cover. The lender will lend them 70% of the value of the house. The couple bought the house 12 years ago for $ 79,000. The house is financed by a deposit of 20% and a mortgage loan at 30 years and 12%

*asked on May 10, 2019* -
## Math

9. Find the product. –14(8) = ? (1 point) –112 112 –108 –116 10. What is the product of –7 and –12? (1 point) –84 84 –74 74 11. Find the quotient. 36 ÷ (–3) = ? (1 point) 13 –13 –12 12 12. What is the quotient of –24 and 8? (1

*asked on May 8, 2019* -
## Math

If the hypotenuse of a triangle is 15 yds, and one leg is 12 yds, what is the length of the other leg? Also how do you find the answer

*asked on November 21, 2018* -
## social studies

1. la salle had conflics with which of the following groups of american indiands? hasinai caddo apache karankawa my answer is d 2. what happened when the spanish found the french colony they engaged the french settlers in warfare and killed many of them

*asked on September 22, 2018* -
## history

Why was it smart for European colonial powers to wield power in their newly-acquired colonies through indirect rule? Can you draw parallelisms with previous dominant civilizations?

*asked on June 16, 2017* -
## Chemistry

Initially a 1 L vessel contains 10 moles of NO2 and 6 moles of O2. At equilibrium, the vessel contains 8.8 moles of NO2. Determine Kc. Please help

*asked on May 9, 2017* -
## Math

A ramp has been rise of 1.5 m for every 12 m of run. What is the slope of the ramp?

*asked on February 27, 2017* -
## bio

The human egg cell above is magnified using a 10´ ocular lens and a 40´ high power objective lens. (a) Calculate the overall magnification. (b) If the field of view at high-power magnification is 400 mm, calculate the size of the field of view when the

*asked on January 7, 2017* -
## Math

What is 3/5 of 25?

*asked on December 14, 2016* -
## health

List sources of internal pressure and external pressure

*asked on June 2, 2016* -
## Math

What is the probability of winning the jackpot if you play the Florida lotto? What is the probability of winning that jackpot if you play Mega Millions? What is the probability of winning the jackpot if you play Powerball?

*asked on March 31, 2016* -
## Physics

Calculate the momentum of a bullet moving with a velocity of 1000m/s ,if it has a mass of 0.01kg

*asked on December 13, 2015* -
## Chemistry

We did a titration lab, and one of the post-lab questions says: "the manufacturer of the vinegar used in this experiment claims that the vinegar contains 5% acetic acid by weight. Use your results and a density of 1g/mL to determine if this claim is true

*asked on October 14, 2015* -
## science

in this experiment, 3 sets of plants were grown. one set had no light, one set had some light, one set had full sun. each set was given the same amount of water, the same temperature, the same soil and it was the same plant and same pot. in 21 days this is

*asked on October 8, 2015* -
## math

in this experiment, 3 sets of plants were grown. one set had no light, one set had some light, one set had full sun. each set was given the same amount of water, the same temperature, the same soil and it was the same plant and same pot. in 21 days this is

*asked on October 8, 2015* -
## College Algebra

Find all real numbers x satisfying the equation: 2^x + 3^x - 4^x + 6^x - 9^x = 1. Please help me. I really don't know what to do.

*asked on January 26, 2015* -
## Algebra 1

I've tried so hard on this and I'm completely hopeless, can somebody help me out? Please it would mean a lot. Task 1 find the rate of change for each table, equation, or graph. How did you find the rate of change? Task 1 A. X 2 4 6 Y 10 20 30 Rate of

*asked on December 20, 2014* -
## Math, Please Help! I don't understand!

I need help because I don't understand how to solve this equation. 37. x/a - 1 = y/b for x So... does it mean solve for x? 39. V = 1/3 * pi * radius^2 * h for h So... does it mean solve for h? As you can see, I am really confused. Please help.

*asked on November 4, 2014* -
## Physics Help

A circular pond of radius 12 m has a layer of ice 0.25 m thick. On a spring day, the temperature of the water below the ice is 4.0°C and the temperature of the air above is 11°C. What is the rate of heat transfer through the ice, in kW?

*asked on October 28, 2014* -
## Physics

A circular pond of radius 12 m has a layer of ice 0.25 m thick. On a spring day, the temperature of the water below the ice is 4.0°C and the temperature of the air above is 11°C. What is the rate of heat transfer through the ice, in kW?

*asked on October 27, 2014* -
## Physics

(c) On Earth a fit astronaut without a space suit and life support pack can leap straight up and leave the ground with an initial vertical velocity of about v1y = 2.4 m/s and rise to a height of about h = 0.24 m above the point where he first loses contact

*asked on September 17, 2014* -
## Physics

A juggler throws a ball with an initial horizontal velocity of +1.1 m/s and an initial vertical velocity of +5.7 m/s. What is its acceleration at the top of its flight path? Make sure to consider the sign when responding. Consider the upward direction as

*asked on September 13, 2014* -
## Physics

Your projectile launching system is partially jammed. It can only launch objects with an initial vertical velocity of 42.0 m/s, though the horizontal component of the velocity can vary. You need your projectile to land 211 m from its launch point. What

*asked on September 13, 2014* -
## Physics

A juggler throws a ball with an initial horizontal velocity of +1.1 m/s and an initial vertical velocity of +5.7 m/s. What is its acceleration at the top of its flight path? Make sure to consider the sign when responding. Consider the upward direction as

*asked on September 13, 2014* -
## data management

The stay at a hotel on Spring Break is normally distributed with a mean of 7 days and a standard deviation of 2 days. If 8000 people visited this hotel on Spring Break... a) If a visitor stays 6 days what is the corresponding z-score? b) How many visitors

*asked on June 11, 2014* -
## Science

In a fetal pig, what are the 4 lobes of the brain and their functions?

*asked on February 21, 2014* -
## Science (Help, please!)

"Toy Car A" is propelled by elastic force. The other forces acting on the car are gravity (pulling the car down) and friction force (between the car and the floor). What UNBALANCED forces are acting on the car? "Toy Car B" is propelled by air resistance.

*asked on December 19, 2013* -
## Science (Balanced/Unbalanced Forces)

"Toy Car A" is propelled by elastic force. The other forces acting on the car are gravity (pulling the car down) and friction force (between the car and the floor). What UNBALANCED forces are acting on the car? "Toy Car B" is propelled by air resistance.

*asked on December 19, 2013* -
## math

11:15 a.m. until 12:50PM WHAT IS THE ELAPSED TIME

*asked on November 16, 2013* -
## MATH

Fabio said that there are 3 times as many people on a basketball team as on a tennis team. Is he correct? Explain why or why not.

*asked on October 17, 2013* -
## Physical Science

Which of the following is a single replacement? a. KOH + HCl --> KCl + H2O b. 2Na + 2H2O --> H2 + 2NaOH c. 2C2H6 + 7O2 --> 4CO2 + 6H2O d. H2O + CO2 --> H2CO3 Any help would be appreciated, thank you in advance!

*asked on October 11, 2013* -
## Algebra 1

A vending machine had to be programmed to accept any combination of nickels, dimes, and quarters that totals 40 cents. How many different combinations are possible?

*asked on October 7, 2013* -
## chem

how many mL of .135M Sr(OH)2 are needed to neutralize 35ml of .157M HCL I know the answer came out to 20.4 ml My only question is how do I convert HCL to Sr(OH)2

*asked on September 29, 2013* -
## vocabulary

How do you parse these words? 1. Rendition 2. Ambiguous 3. Deleterious 4. Euphemism 5. Alacrity 6. Respite 7. Polemical 8. Timorous 9. Adulation 10. Eschew

*asked on September 26, 2013* -
## World History

How did Renaissance thinkers think the individual was defined? Explain how this idea can be compared with the value of an individual in ancient Roman and medieval European societies. Any help with this question would be greatly appreciated. Please and

*asked on September 11, 2013* -
## algebra

The Environmental Protection Agency set a standard of 50 parts per billion of lead in drinking water. A new standard was set that safe water contains less than 15 parts per billion. a) write each of these rates as fractions using positive powers of ten. b)

*asked on August 26, 2013* -
## Grade 12 Calculus

State the absolute maximum value and the absolute minimum value of each function, if the function is defined on the interval shown. {I CANNOT POST THE GRAPH SO CAN SOMEONE EMAll ME AT miss.a.parker at hot mail(. com) SO I CAN EMAIL IT TO THEM SO YOU CAN

*asked on April 15, 2013* -
## Science

Assume you can heat water with perfect insulation (all the heat from combustion of ethanol is transferred to water). What is the volume of ethanol required to heat 100 mL of water by 10 degrees C? (You will need to look up density of ethanol, specific heat

*asked on March 21, 2013* -
## statistics

. A certain researcher thinks that the proportion of women who say that female bosses are harshly critical is greater than the proportion of men. In a random sample of 200 women, 27% said that female bosses are harshly critical. In a random sample of 220

*asked on November 28, 2012* -
## physics

A 16.0-N weight slides down a rough inclined plane that makes an angle of 28.0° with the horizontal. The weight, which started from rest, gains a speed of 15.0 m/s after sliding 150 m. How much work is done against friction?

*asked on August 29, 2012* -
## Exploring Multiplication

how can you find out how many slices your class needs if each pizza has 8 slices and ther are 28 kids?

*asked on March 29, 2012* -
## Chemistry

If the concentration of a reactant is decreased, will the speed of the reaction increase or decrease? Explain. I understand that if the concentration of a reactant is INCREASED, the frequency of coliision increases, making the rate of reaction increase.

*asked on January 31, 2012* -
## Chemistry

So I do know how to work out letter a) but I'm still very confused with parts b and c. Appreciate the help! 2FeN(s) + 3H2(g) --> 2Fe(s) + 2NH3(g) Suppose that the reaction is carried out at 300C and 3.00 atm. 1.00 grams of iron (III) nitride reacts. a)What

*asked on January 22, 2012* -
## Desert

How are deflation hollows made? Could you also give me some more pictures of hoodoos (the landforms)?

*asked on October 29, 2011* -
## math

A green purse costs $11, which is 11 times as much as a red tie costs. How much does the red tie cost?

*asked on October 7, 2011* -
## math

To solve for the following proportion, you could use equivalent ratios, divide out the known ratio, or use cross products. Choose one of these methods to solve for t. Show your work and explain why you chose that method. 18/5 = 4/t

*asked on June 6, 2011* -
## math

A plane flying with a constant speed of 14 km/min passes over a ground radar station at an altitude of 7 km and climbs at an angle of 35 degrees. At what rate, in km/min, is the distance from the plane to the radar station increasing 5 minutes later?

*asked on May 24, 2011* -
## Calculus

The base of a solid is bounded by y=2sqrtx, y=2 and x=4. Find the volume of solid if cross sections perpendicular to y=2 are semicircles

*asked on April 17, 2011* -
## Chemistry

How many moles of acetic acid are there in 25 mL container?

*asked on March 10, 2011* -
## phoenix

The library is an excellent sources and option. What are some other public option? examples & explanation.

*asked on February 10, 2011* -
## statistics

Assume the IQ's of men and women can be described by a Normal model with a mean of 100 and a standard deviation of 15. For the first part: What percent of people do you expect to have IQ's over 120?

*asked on February 8, 2011* -
## Algebra

A candy cane 30 cm high has a circumference of 3 cm. The red “ribbon” makes exactly 4 complete turns round the candy cane while its two ends touch the cane's top and bottom. How long is the ribbon in cm? It doesn't make any sense to me. Can somebody

*asked on February 1, 2011* -
## 6th grade

how do you do rate of change?

*asked on December 8, 2010* -
## college alg help!

cannot figure a way to do this problem: An investment of $98,000 was made by a business club. The investment was split into three parts and lasted for one year. The first part of the investment earned 8% interest, the second 6%, and third 9%. The total

*asked on November 18, 2010* -
## Chemistry

In the study of biochemical processes, a common buffering agent is the weak base trishydroxymethylaminomethane, often abbreviated as Tris. At 25 C, Tris has a pKb of 5.91. The hydrochloride can be abbreviated as Tris HCl. What volume of 10.0 M NaOH is

*asked on November 14, 2010* -
## 6th grade

Can you simplify 9 over 16?

*asked on October 26, 2010* -
## chemistry

what is the density of 700 ml of a gas that has a mass of 7 g?

*asked on September 6, 2010* -
## chemistry

how many joules are formed when 3 moles oh CH4(g) react?

*asked on March 21, 2010* -
## Chemistry

A gas storage tank has a volume of 3.5*10^5 m^3 when the temperature is 27 degrees celcius and the pressure is 101 kPa. What is the new volume of the tank if the temperature drops to -10 degrees celcius and the pressure drops to 95 kPa?

*asked on February 23, 2010* -
## math

The quotient of two numbers is 8. The sum of the same two numbers is 72. What is the two numbers

*asked on February 10, 2010* -
## college physics

Let's say that you find a slope of 6.671×10-14 for square plates of width 11.5 cm. What do you get for the value of the permittivity of free space?

*asked on January 24, 2010* -
## physics

A 20.0kg mass is placed a the top of a 3.5m long, 15degree ramp. When released from rest, the mass accelerates down the ramp. The frictional force acting on the mass is 11.0 N. What is the velocity of the mass at the bottom of the ramp.

*asked on December 9, 2009*

## Pages

**1**- 2