# luis

Most popular questions and responses by luis-
## chemistry

Complete and balance each of the following equations. K2SO4(aq)+BaBr2(aq)→ Would it be K2SO4(aq)+BaBr2(aq)→K2Br2 +SO4Ba? Express your answer as a chemical equation. Enter no reaction if no precipitate is formed. (How can we know if a solid is formed in

*asked on September 30, 2014* -
## social studies

which demonstrates how the Anasazi adapt to their hot dry environment? A the Anasazi moved south where more water as available. B the Anasazi hunted bison for food and clothing. C the Anasazi built permanent dwellings in the side of cliffs. D the Anasazi

*asked on October 5, 2018* -
## Calculus

The minute hand of a clock is 6in long. Starting from noon, how fast is the area of the sector swept by the minute hand increasing in in^2/min at any instant?

*asked on December 14, 2009* -
## Chemisty

How many grams of Cl are in 38.0g of CF2Cl2? I really want to figure out how to do it. I can't seem to understand any of this Chem homework and it's getting me frustrated, please help!

*asked on September 26, 2014* -
## physics

An engine moves a motorboat through water at a constant velocity of 22 meters/second. If the force exerted by the motor on the boat is 5.75 × 103 newtons, what is the power of the motor?

*asked on January 11, 2013* -
## Physics, Math

A typical volume of a modern hot air balloon is 2500 cubic metres, and a typical maximum temperature of the hot air is 120 degrees Celsius. Given these figures, and an outside air temperature and density of 15 ∘C and 1.225 kg/m3 respectively, compute the

*asked on September 2, 2014* -
## Math

A wall in Marcus's bedroom is 8 1/3 feet high and 16 1/5 feet long. If he paints 1/3 of the wall blue, how many square feet will be blue?

*asked on December 21, 2016* -
## Math

Use similar triangle to solve. A person who is 6 feet tall standing 140 feet from the base of a tree and the tree casts a 150 foot shadow. The person's shadow is 10 feet in length. What is the height of the tree?

*asked on November 17, 2015* -
## math

find the sum and product of the roots of the equation 5x^2+11x-3=0 ?

*asked on January 18, 2011* -
## chemistry

How long does it take light to travel each of the following distances 2462 mi, the distance between Los Angeles and New York. How do we calculate how fast light travels?

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

A baggage handler throws a 16.0 kg suitcase horizontally along the floor of an airplane luggage compartment with an initial speed of 1.10 m/s . The suitcase slides 2.10 m before stopping.

*asked on November 18, 2015* -
## physics

A warehouse worker pushes a crate along the floor, as shown in the figure (Figure 1) , by a force of 9.0N that points downward at an angle of 45∘ below the horizontal. Q1 Find the horizontal component of the push Q2 Find the vertical component of the

*asked on February 12, 2015* -
## Personal Finance (Math)

Becka borrowed $100 from her cousin at the rate of 6% per year. If the inflation rate was 2% that year, what is her cousin's actual rate of return on the loan? How do you work this out?

*asked on September 27, 2014* -
## PHysics XXX

An airplane travels 330 m down the runway before taking off. Assuming that it has constant acceleration, if it starts from rest and becomes airborne in 9.00 s, how fast (in m/s) is it moving at takeoff? A 73.3 m/s B 36.7 m/s C 1490 m/s D 660 m/s

*asked on March 25, 2014* -
## Math

A pill weighs 70 mg. 7/9 of the pill is the active ingredient. How many milligrams are in the part of the pill that is not the active ingredient? So if 7/9 is active that means 2/9 is not active. I did 2 divided by 9 which gives me .22 I then multiplied 70

*asked on January 31, 2015* -
## Physics

A sports car skids to a stop, leaving skid marks 290 m long. If the coefficient of kinetic friction between tires and pavement is 0.80, how fast was the car going before the skid?

*asked on October 4, 2015* -
## Physics

A string is tied to a 4.4 kg block and a 120 g hanging bucket. students add 20 g washers one at a time to the bucket. the students are unaware that the coefficient of static friction for the block on the table is 0.42. What is the maximum force of static

*asked on October 9, 2011* -
## trig

How do I find the exact value of sin (pi/24)?

*asked on March 17, 2013* -
## English

Hello, I am asking for these to be reviewed. I do not want answers; I just want to know if these answers look good. If you would just tell me which ones are wrong and why? Thank you for any help. Eliminate unnecessary shifts in tense, mood, voice, or

*asked on December 14, 2011* -
## chemisrty

what is the strongest acid here? H2SO3 H2SO4 H2SeO3 H2SeO4 For oxyacids, the acidity increases with increasing number of oxygen atoms; therefore, H2SO3 and H2SeO3 will be weaker than either H2SO4 or H2SeO4. We have a problem determining which is the

*asked on April 30, 2007* -
## english - Compare and Contrast

I would appreciate it if someone would be willing to look over my essay real quick. I just would like to know if I made any critical errors. Please do not correct them just point them out so I can fix it. Thank you very much. General instructions from my

*asked on January 19, 2015* -
## chemistry

Imagine that you have an ideal gas in a 8.00L container, and that 2850 molecules of this gas collide with a square-inch area of the container at any given instant. If the volume is increased to 56.0L at constant temperature, how many collisions will occur

*asked on October 30, 2014* -
## physics

A beam of protons is moving toward a target in a particle accelerator. This im trying to study for my exam by doing problems, however im stuck with this one. any help is appreciated beam constitutes a current whose value is 0.39A. (a) How many protons

*asked on September 26, 2012* -
## Calculus

Express the following in Sigma notation 2+8+18+32+50+72

*asked on January 5, 2010* -
## Calculus

The voltage,V, in an electrical unit is related to the current,I, and the resistance,R, by the equation V=IR. The current is decreasing at -4amps/sec as the resistance increases at 20ohms/sec. How fast is the voltage changing when the voltage is 100 volts

*asked on December 14, 2009* -
## Physics

a thimble is 32.0 cm from a spherical concave mirror. The focal point lenght of the mirror is 11.0 cm. What is the image position?

*asked on May 2, 2010* -
## math

why did king kong eat a truck?

*asked on April 20, 2009* -
## chemistry

Magnesium has three naturally occurring isotopes: Mg-24 with mass 24.3050 amu and a natural abundance of 78.99 %, Mg-25 with mass 24.9858 amu and a natural abundance of 10.00 %, and Mg-26 with mass 25.9826 amu and a natural abundance of 11.01 %. Calculate

*asked on December 14, 2014* -
## math

Tanishas mother buys 38 lemons. they know it takes 8 lemons to make 80 ounces of leomonade. Does Tanisha need more lemons? If not, how many extra lemons does she have? if so, how many more lemons does she need? explain how you found your anwser. she needs

*asked on December 30, 2016* -
## English

I need to double check my work please. Revise to create pronoun-antecedent agreement and eliminate the generic he and any awkward pronoun reference. 1) While shopping for a new computer for school, I noticed that a laptop costs much less then they use to.

*asked on December 17, 2011* -
## mathematics

show step solve the Sturm Liouville problem Y"+hY=0, NB: h means lambda y(0)+y'(0)=0 y(1)+3y'(1)=0 obleck plz explain better again or damon can you help

*asked on February 8, 2019* -
## Series RL circuits

A series RL circuit contains two resistors and two inductors. The resistors are 43 ? and 54 ?. The inductors have inductive reactances of 70 ? and 40 ?. The total impedance is _____.

*asked on March 9, 2018* -
## Physics

A baseball is thrown at an angle of 25 degrees relative to the ground at a speed of 23.0 m/s. If the ball was caught 42.0 m from the thrower, how long was it in the air? How high was the tallest spot in the ball's path?

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

You have two gas-filled balloons, one containing He and the other containing H2. The H2 balloon is twice the size of the He balloon. The pressure of gas in the H2 balloon is 1 atm, and that in the He balloon is 2 atm. The H2 balloon is outside in the snow

*asked on March 30, 2007* -
## Math

show step solve the Sturm Liouville problem Y"+hY=0, NB: h means lambda y(0)+y'(0)=0 y(1)+3y'(1)=0

*asked on February 7, 2019* -
## chemistry

A 27.00mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1422M KOH solution. A volume of 40.22mL of KOH was required to reach the equivalence point. What is the concentration of the unknown H2SO4 solution? Any help would be

*asked on December 14, 2014* -
## chemistry

Calculate the freezing point of a water solution at each concentration. 1.40m? What are the steps to calculate this?

*asked on November 19, 2014* -
## Math, Geomertry

A total solar eclipse occurs when the moon passes between the earth and the sun, and the darkest shadow cast by the moon, called the umbra, hits the surface of the earth. If the umbra does not hit the surface, as shown in the following figure, then a total

*asked on April 4, 2014* -
## English

Can anyone help me with these. I need to eliminate unnecessary shifts in tense, mood, voice, or person. 1)The greed of the 1980’s gave way to the occupational insecurity of the 1990’s, which in turn gave way to reinforced family ties in the early

*asked on December 14, 2011* -
## Calculus

Express the following in Sigma notation 2+8+18+32+50+72

*asked on January 5, 2010* -
## math

A stone is dropped from a cliff 344 feet high. after how many seconds will it be 200 feet above the ground?

*asked on April 11, 2014* -
## geo

Jackson is creating a water garden surrounded by a triangular patch of grass. If the pond will take up the space indicated by the circle, how many square feet of sod will he need to complete the garden (use 3.14 for and round your answer up to the next

*asked on May 9, 2013* -
## chemistry

What is the molarity of ZnCl2(aq) that forms when 18.0g of zinc completely reacts with CuCl2(aq) according to the following reaction? (Assume a final volume of 165mL .) Zn(s)+CuCl2(aq)→ZnCl2(aq)+Cu(s)

*asked on November 19, 2014* -
## chemistry

Calculate the theoretical yield of alum if 0.200g of Aluminum was reacted with excess KOH and H2SO4? I don't even know how to start it. Please help. Also I wanted to say thank you for the help I've gotten from this website it has helped me a lot. I feel

*asked on October 16, 2014* -
## Physics

A battery has an internal resistance of 0.42. A number of identical light bulbs, each with a resistance of 31.500, are connected in parallel across the battery terminals. The terminal voltage of the battery is observed to be one-half the emf of the

*asked on September 26, 2012* -
## English

Can anyone help me check my work please. I need to revise the paragraph to establish a clear antecedent for every pronoun that needs one. Original: In the summer of 2005, the NCAA banned the use of mascots that could be considered offensive to American

*asked on December 18, 2011* -
## chemistry

Which is the correct expression for Keq when the chemical reaction is as follows: N2 + 3H2 2NH3.

*asked on November 16, 2015* -
## chemistry

onsider the following reaction between sulfur trioxide and water: SO3(g)+H2O(l)→H2SO4(aq) A chemist allows 61.5 g of SO3 and 11.2 g of H2O to react. When the reaction is finished, the chemist collects 59.3 g of H2SO4.

*asked on October 9, 2015* -
## physics

A car entering the freeway accelerates from 10.2 m/s with a constant acceleration of 4.4 m/s2. What is the car’s final velocity when it merges onto the highway and reaches its cruising speed 4.2 seconds later? A 28.7 m/s B 11.2 m/s C 18.5 m/s D 8.28 m/s

*asked on March 25, 2014* -
## Physics

A simple pendulum consists of a light string 1.70 m long with a small 0.490 kg mass attached. The pendulum starts out at 45^\circ below the horizontal and is given an initial downward speed of 1.50 m/s. At the bottom of the arc, determine the centripetal

*asked on June 25, 2011* -
## AP Biology

Why are Eukaryotes more difficult to Transform than Prokaryotes? What methods can be used to transform Eukaryotes?

*asked on April 14, 2014* -
## math

Which correctly renames 2/3 and 1/2 using a common denominator??

*asked on January 20, 2016* -
## 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!)

*asked on September 27, 2014* -
## Pre calculus

P=(-2,2) Q=(3,4) S=(2,-8) PS-3PQ Find the component form and magnitude of the vector.

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

Two identical springs (neglect their masses) are used to “play catch” with a small block of mass 200 g (see the figure). Spring A is attached to the floor and compressed 10.0 cm with the mass on the end of it (loosely). Spring A is released from rest

*asked on July 3, 2011* -
## physics

A simple pendulum consists of a light string 1.70 m long with a small 0.490 kg mass attached. The pendulum starts out at 45^\circ below the horizontal and is given an initial downward speed of 1.50 m/s. At the bottom of the arc, determine the centripetal

*asked on June 25, 2011* -
## physics

A simple pendulum consists of a light string 1.70 m long with a small 0.490 kg mass attached. The pendulum starts out at 45^\circ below the horizontal and is given an initial downward speed of 1.50 m/s. At the bottom of the arc, determine the centripetal

*asked on June 25, 2011* -
## Math

My son has a homework (Kindergarden) where he has numbers and next to it there are five square frames. The numbers are 3 and 4. The instructions are as follows: Place counters in the five frames to show the number. Draw counters. Trace the number. What are

*asked on September 23, 2010* -
## Chemistry

A solution of acetic acid, 1.0 mol L–1 CH3COOH, contains sodium acetate, NaCH3COO. The percent ionization of the above solution is 0.25%. The Ka for acetic acid is 1.8 x 10–5. Which of the following is the concentration of NaCH3COO in acetic acid? So

*asked on June 9, 2016* -
## Science

Christina has a glass of water. Michael has a fruit juice drink. Both drinks are at room temperature, and both students add ice to their drink's. Condensation begins to on the outside of Christina's glass before Michael's. How can they state their

*asked on March 30, 2016* -
## Math

An oil-drilling company knows that it costs $25,000 to sink a test well. If oil is hit, the income for the drilling company will be $375,000. If only natural gas is hit, the income will be $165,000. If nothing is hit, there will be no income. If the

*asked on March 13, 2013* -
## Physic

Calculate the average speed of an oxygen molecule (with a mass of 5.3e-26 kg) at room temperature (300 Kelvin)show your work

*asked on July 22, 2012* -
## Ochem

By looking at the chemical structures of acetaminophen, aspirin, caffeine, ibuprofen, and naproxin sodium, how are you able to determine the relative polarity of each? Does it have something to do with the symmetry of the structure? Please help!

*asked on October 18, 2011* -
## physics

Two identical springs (neglect their masses) are used to “play catch” with a small block of mass 200 g (see the figure). Spring A is attached to the floor and compressed 10.0 cm with the mass on the end of it (loosely). Spring A is released from rest

*asked on July 3, 2011* -
## math

2.-The longest one-word name of any place in America is Chargoggagoggmanchauggagoggchubunagungamaugg.This name for a lake near webster, Massachusetts, is 45 letters long. It is a Native American name that means "You fish on you side, I'll fish on mine, and

*asked on January 29, 2011* -
## 10th grade

its werid finiding 8x - 13 and 7x + 11 but idk if i should add and equl to 360 its paralleograms and finding x its a triangle please help

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

if a spinning amusement-park ride has an angular speed of 1.2 rad/s, what is the centripetal acceleration of a person standing 12m from the center of the ride?

*asked on November 24, 2009* -
## Science

Christina has a glass of water. Michael has a fruit juice drink. Both drinks are at room temperature, and both students add ice to their drink's. Condensation begins to on the outside of Christina's glass before Michael's. How can they state their

*asked on March 30, 2016* -
## physics

A football is thrown with an initial upward velocity component of 13.5m/s and a horizontal velocity component of 16.5m/s How much time is required for the football to reach the highest point in its trajectory? How high does it get above the ground?How much

*asked on February 18, 2015* -
## pre-calculus

Currently in school we're learning about proving identities and for extra credit I got this problem. cosB= -8/17 in quad II and I have to find sin 7B. I have gotten this far: sin7B= sin(3B+4B) sin3Bcos4B+sin4Bcos3B my problem I can't figure out how to

*asked on May 13, 2012* -
## English

Would someone please check my work. I need to combine the following sentences into one by using a semicolon. 1)Abalone fishing in California is strictly regulated. A person is allowed to harvest only twenty-four of these large mollusks per year. A)Abalone

*asked on December 20, 2011* -
## Physics

two binary stars moving in a perfect circle orbit The stars have the same mass, the distance between them is one billion km (1x10^9 km), and the time each takes for one orbit is 10.4 Earth years. Determine the mass of each star (m1=m2). (this problem

*asked on June 25, 2011* -
## Calculus

An inverted cone has a diameter of 42 in and a height of 15in. If the water flowing out of the container is 35pi in^3/sec , how fast is the depth of the water dropping when the height is 5in?

*asked on December 13, 2009* -
## Math

Estimate the value of 51 to the nearest whole number

*asked on June 13, 2017* -
## math last set up

To secure a 618 meter radio tower against high winds, guy wires are attached to a ring 10 meters from the top of the tower. Each wire is anchored 90 meters from the base of the tower. Find the measure of the angle the wire makes with the ground. Round your

*asked on May 22, 2014* -
## math

bystander at the Pegasus Parade, is lying on his back and observing a large balloon of a cartoon character, floating directly above Broadway Street. He is located 32 feet from a point on the street directly beneath the balloon. To see the top of the

*asked on May 22, 2014* -
## pHYSIC

5. Now, wait until the planet is at the winter solstice (12:00am). a) How many hours of daylight are there on the winter solstice with the inclination at 45 degrees? Use the same criteria for the length of day that you used for the previous question. b)

*asked on July 15, 2012* -
## Chemistry

When 3.00 g potassium carbonate (K2CO3 ) was mixed with 20.0 mL of hydrochloric acid (HCl, 4.0M) in a calorimeter, the temperature raised 3.0 degrees Celsius. B. Calculate the enthalpy change (H) of the reaction for per mole patassium carbonate. Assume

*asked on April 15, 2012* -
## ENGLISH

I need to make sure I understand this. I need to rewrite each sentence twice, once as a periodic sentence and once as a cumulative sentence. To me, both look like cumulative sentences though, so I am a little confused. If someone could check my work I will

*asked on December 28, 2011* -
## Physics

A vertical spring with a force constant of 250 N/m is compressed 7.5 cm and a 0.30 kg ball placed on top. The spring is released and the ball flies vertically upward. How high does the ball go? (thanks for helping)

*asked on July 3, 2011* -
## Physics

Water is lifted out of a well 25.0 m deep by a motor rated at 1.50 hp. Assuming efficiency 90%, how many kilograms of water can be lifted in 1 min?

*asked on July 3, 2011* -
## uh manoa

A basket of neglible wieght hangs from a vertical spring scale of constant force 1500N/m. If you sundally put a 3.0 Kg adobe brick in the basket, find the maximum distance that the spring will stretch. If, instead, you released the brick from 1.0 m above

*asked on June 8, 2011* -
## language-poetrypart 1

When a poet wishes to use figurative language he or she will use words that are a)Commotativo and denotativo b) Only denotativo c) Only commotativo d) Ambiguous

*asked on October 22, 2010* -
## chem plz help!

the rate of a nuclear reaction can be changed by?? i know adding a catalyst to a normal reaction can but to a nuclear im not sure. increasing temp decreasing pressure adding a catalyst none I suppose it all depends upon how you define a catalyst. Perhaps

*asked on April 30, 2007* -
## words problems

a car rental offers two plans-plan a $20per day and 12 cents per mile -plan b -$65 per day free unlimited mileage

*asked on October 25, 2015* -
## Math

My 10th grade teacher gave us geometry homework and this problem has me stumped for sure. This rhombus has three interior angles: (5x-2)°, (8y+2)°, and (3x+22)° . We are supposed to find the value of x and y. I tried to use an equation by assigning the

*asked on March 12, 2015* -
## Stats

A classroom of n = 10 children has a mean score of 17.200 on a measure of hyperactivity. One new child is added to the class, and the mean hyperactivity score for the resulting classroom including all the children is 18.000. Find the value of the new

*asked on January 31, 2015* -
## Math

Show 2/4 of the set. How many counters?

*asked on April 16, 2014* -
## Math, Geometry

The percent grade of a highway is the amount that the highway raises or falls in a given horizontal distance. For example, a highway with a four percent grade rises 0.04 mile for every 1 mile of horizontal distance. a. How many feet does a highway with a

*asked on April 4, 2014* -
## chemistry

You wish to increase the carbon content of a slab of steel by exposing it to a carburizing atmosphere at elevated temperature. The carbon concentration in the steel before carburization is 490.5 ppm and is initially uniform through the thickness of the

*asked on December 14, 2012* -
## Physic

You must show your work for full credit.) Calculate the average speed of an oxygen molecule (with a mass of 5.3e-26 kg) at room temperature (300 Kelvin):

*asked on July 22, 2012* -
## astronomy

big bang theory define

*asked on July 15, 2012* -
## physics

a dog runs down his driveway with an initial velocity of 4.0 m/s. the dog then accelerates at 2.5 m/s^2 for 5.0 s. what is the final velocity of the dog?

*asked on September 22, 2011* -
## Physics

If a person runs the 100m dash in 10.0s, calculate that speed in m/s and km/h.

*asked on September 11, 2011* -
## Physics

A simple pendulum consists of a light string 1.70 m long with a small 0.490 kg mass attached. The pendulum starts out at 45º below the horizontal and is given an initial downward speed of 1.50 m/s. find: At the bottom of the arc, determine the centripetal

*asked on June 25, 2011* -
## lenguage poetry

It hills bent .law within my reach How many fats this line contain 5, 4, 6, 7,

*asked on October 22, 2010* -
## Math

My son has a homework (Kindergarden) where he has numbers and next to it there are five square frames. The numbers are 3 and 4. The instructions are as follows: Place counters in the five frames to show the number. Draw counters. Trace the number. Please

*asked on September 23, 2010* -
## Science

Christina has a glass of water. Michael has a fruit juice drink. Both drinks are at room temperature, and both students add ice to their drink's. Condensation begins to on the outside of Christina's glass before Michael's. How can they state their

*asked on March 30, 2016* -
## Chemistry

what mass of NaCl do you need to make a 500mL of a 0.10M solution?

*asked on March 28, 2016* -
## physics

A water-skier is being pulled by a tow rope attached to a boat. As the driver pushes the throttle forward, the skier accelerates. A 83.0-kg water-skier has an initial speed of 5.9 m/s. Later, the speed increases to 11.4 m/s. Determine the work done by the

*asked on December 5, 2015*