# Posts by Chris

Total # Posts: 2,693

**Chemistry**

how many moles of sodium oxide are produced when 3.9 moles of of sodium combine with excess oxygen

*January 29, 2013*

**Math - 8th Grade**

I need help please. I answered (c)incorrectly. Chantal and Julia ride horses in the same race. Chantal's horse finishes in one minute and 59.53 seconds. If Julia's horse runs 2.25 percent slower than Chantal's, how long does it take Julia's horse to finish the ...

*January 25, 2013*

**Math - 8th Grade**

I need help please. I answered (c)incorrectly. Chantal and Julia ride horses in the same race. Chantal's horse finishes in one minute and 59.53 seconds. If Julia's horse runs 2.25 percent slower than Chantal's, how long does it take Julia's horse to finish the ...

*January 25, 2013*

**Science**

The intensity of an earthquake wave passing through the Earth is measured to be 1.5×10^6 J/m^2*s at a distance of 58km from the source. What was its intensity when it passed a point only 2.0 km from the source? At what rate did energy pass through an area of 3.0 m^2 at 2...

*January 25, 2013*

**math**

are you sure this is right

*January 23, 2013*

**pre- algebra**

i put b i got it rong and it cant be c so its either a or d i think a

*January 22, 2013*

**pre- algebra**

Write a rule for the linear function in the table. x f(x) 1 3 2 2 3 1 4 0 A. f(x) = 4x B. f(x) = x – 4 C. f(x) = x + 4 D. f(x) = 4 – x

*January 22, 2013*

**chemistry**

What would be the concentration of dinitrogen pentoxide after 6.00 X 10(2) seconds and how long would it take for the concentration of N2O2 to decrease to 10.0% of its initial value in the following equation... N2O5 to NO2 and O2 initial concentration is 1.65 X 10-2mol/L rate ...

*January 21, 2013*

**Chemistry**

This problem is 1st order for half life. How long would it take for the concentration of cyclopropane to decrease to 50% of its initial value? to 25% of its initial value? Rate constant is 9.2/s I set up like this... t1/2= 0.693/9.2/s= 0.075s at 50% I can't figure out how ...

*January 21, 2013*

**Chemistry**

So, to solve for t would I set up the problem like this... ln (0.00124/0.0165)=4.80 X 10-4 X t?

*January 20, 2013*

**Chemistry**

What would be the concentration of dinitrogen pentoxide after 6.00 X 10(2) seconds and how long would it take for the concentration of N2O2 to decrease to 10.0% of its initial value in the following equation... N2O5 to NO2 and O2 initial concentration is 1.65 X 10-2mol/L rate ...

*January 20, 2013*

**Chm**

What is the molarity of a saturated solution of potassium sulfate if the solubility is 13 g per 100 g H2O at 25°C? The density of the solution is 1.1 g/mL

*January 17, 2013*

**world civilization**

What motivated western Europeans to explore and colonize in the wider world?

*January 14, 2013*

**assembler language**

write an assembly language subordinate count according to these specs: accepts a pointer to an array or signed words in register X. Accepts a word value in register Y, which indicates the number of array elementsl Returns the number (i.e. count) of nonzero array elements in ...

*January 12, 2013*

**Algebra 1**

2540 bikes

*January 9, 2013*

**Algebra 1**

A bicycle store costs $2400 per month to operate. The store pays an average of $60 per bike. Then average selling price of each bicycle is $120. How many bicycles must the store sell each month to break even?

*January 9, 2013*

**Geography**

The waters surrounding Japan and the nearby ocean currents help to make Japan's climate mostly what?

*January 8, 2013*

**HELPP math**

The choices for the variance A. 231 B. 616.2 C. 685.2 D. 1,197.2 The choices for the standard deviation A.0.2 B.24.83 C.26.18 D.34.61

*December 29, 2012*

**HELPP math**

13,14,29,26,41,53,60,7,89,14 Based on the numbers above what is the variance and the standard deviation of the data set. I think 616.2 is the variance I think 24.83 is the standard deviation Am I correct????

*December 29, 2012*

**math**

i am a 3 digit number,my middle number is double the other two which are square numbers,what is the number

*December 25, 2012*

**Math - Need help please**

There are 1,800 students at a high school. Of the students who have smoked at least one cigarette in the last month, five-eighteenths are twelfth graders. Thirty-five percent of the remaining students are eleventh graders, and the rest are in the ninth and tenth grades. If ...

*December 18, 2012*

**Math**

There are 1,800 students at a high school. Of the students who have smoked at least one cigarette in the last month, five-eighteenths are twelfth graders. Thirty-five percent of the remaining students are eleventh graders, and the rest are in the ninth and tenth grades. If ...

*December 18, 2012*

**grade 12 math**

i don't understand alg 2

*December 18, 2012*

**trigonometry**

The answer for number 4 is wrong, Cotangent means adj/opp so it would be -15/8

*December 13, 2012*

**Math - 8th grade**

Express 18 million in scientific notation. I answered 1.8 x 10 to the 7th and was wrong. I don't understand why? You are supposed to move the decimal 7 places to get 18 million. What did I do wrong? Thank You.

*December 12, 2012*

**8th Grade Math**

Express 18 million in scientific notation. I answered 1.8 x 10 to the 7th and was wrong. I don't understand why? You are supposed to move the decimal 7 places to get 18 million. What did I do wrong? Thank You.

*December 12, 2012*

**Health**

Appropriate cooking methods are cost efficient because?

*December 12, 2012*

**Math**

Alyssa, Bert, and Cara are running for school president. Alyssa receives two-sevenths of the votes. Bert receives sixty-five percent of the remaining votes, and the rest of the votes go to Cara. If Cara receives 315 votes, how many votes were there in all? Please help with ...

*December 11, 2012*

**Chemistry**

Consider a 0.71 M solution of each of the following salt dissolved in distilled water. Will the solution by basic, neutral, or acidic? KI= NH4NO2= (CH3CH2)3NHNO2= (CH3CH2)2NH2ClO4=

*December 11, 2012*

**Chemistry**

a 0.451 L solution of 1.71 ascorbic acid (ka1=7.9E-5, ka2=1.6E-12) is titrated with 1.35 M NaOH. What is pH when 0.9540 L of NaOH is added?

*December 11, 2012*

**Consumer math**

900 = 466.2 = The mean is

*December 11, 2012*

**algebra**

What is the anser to 8x + 6y = 5 for x? I am not looking for the slope of a triangle, just the anser.

*December 10, 2012*

**trig**

An airplane flies with a speed of 425 mph and a heading of 63°. If the heading of the wind is 24°and the speed of the wind is 31 mph, what is the heading of the plane and the ground speed? I've done a couple questions like this but still a little fuzzy on setting ...

*December 9, 2012*

**Chemistry**

23.4

*December 8, 2012*

**8th Grade Math**

Never Mind. Thank You I was doing division instead of multiplying

*December 7, 2012*

**8th Grade Math - Ms Sue**

A ship leaves the East Coast for California. It is traveling at a constant speed of five knots and takes 200 days to reach California. The ship arrives in California at the exact time of day that it left the East Coast. How far did the ship travel? Please help with step by ...

*December 7, 2012*

**8th Grade Math**

A ship leaves the East Coast for California. It is traveling at a constant speed of five knots and takes 200 days to reach California. The ship arrives in California at the exact time of day that it left the East Coast. How far did the ship travel? Please help with step by step.

*December 7, 2012*

**Chemistry**

Consider a 9.5e-10 M solution of HClO4 at 283 K. What is the pH of the solution?

*December 7, 2012*

**physics**

calc the buoyant force on a 2 L helium balloon

*December 6, 2012*

**Physics**

*smaller mass move?

*December 5, 2012*

**Physics**

a 2 kg mass and a 3 kg mass are attached to a lightweight cord that passes over a frictionless pully. the hanging masses are left free to move. a. in what direction will the smaller masses move? b.what will be its acceleration

*December 5, 2012*

**Chemistry**

Diethylamine (C2H5)2NH, is a weak base that ionizes in water,a 0.600 M solution of (C2H5)2NH is 4.65% ionized at 25 degrees Celsius. -Calculate the pH of the solution. -Calculate the Kb for diethylamine.

*December 5, 2012*

**Math - Plz help Ms.Sue**

You must enter 79.7 divided by 6.89. NOT 6.89 divided by 79.97.

*December 5, 2012*

**Math 8th Grade Please help**

The radius of Earth is 6,371 kilometers. A space shuttle orbits 315 kilometers above the surface of Earth. The space shuttle completes 240° of a revolution around Earth in one hour. What is the average speed of the space shuttle? Choose the closest answer. Please help both...

*December 5, 2012*

**psychology**

what is the study called where the same people are tested repeatedly at different ages?

*December 4, 2012*

**Statistics**

I need to know how to find the probability that z0 is greater than or equal to 2.40 using my TI-83+. The answer is .008200, but I don't know how to get that using my calculator. The only reason I know the answer is because it is an example from my homework. Please help! On...

*December 4, 2012*

**Finite Math**

A student dance committee is to be formed consisting of 3 boys and 4 girls. If the membership is to be chosen from 7 boys and 6 girls, how many different committees are possible?

*December 3, 2012*

**Algebra**

The grade of a highway up a hill is 50%. How much change in horizontal distance is there if the vertical height of the hill is 175 feet?

*December 3, 2012*

**Chemistry**

how do you find the pH of a titration solution at its halfway point to the equivalence, and how would it affect solutions dealing with strong acids and strong bases, this is an example just to see it quantitatively: 100.0 mL of 0.100 M HF (Ka = 7.2 x 10-4) by 0.100 M NaOH

*December 1, 2012*

**college physics**

i figured out the first part using the fact that the crate will flip over once the CG is no longer above the crate, and drew a triangle of legs 1.44 m(distance from base of crate to CG), and 1.25m(distance from corner of crate to middle). at first i thought the answer would be...

*December 1, 2012*

**college physics**

A cubic crate of side s = 2.5m is top-heavy: its CG is 19cm above its true center. Part A How steep an incline can the crate rest on without tipping over? Part B What would your answer be if the crate were to slide at constant speed down the plane without tipping over? [Hint: ...

*December 1, 2012*

**Physics**

An object is placed 11 cm in front of a convex mirror of focal length 4 cm. Using the lens equation, find where the image will form and state whether it is a real or virtual image.

*December 1, 2012*

**Math 8th Grade - Ms. Sue please**

After receiving a grant for music education, a school decides to build a new band room for its expanded music program. Quadrilateral ABCD represents the floor plan of the new band room. What is the area of the room? AE = 32 ft. BE = 12 ft. CE = 26 ft. DE = 26 ft. There is a ...

*December 1, 2012*

**Math 8th Grade (Ms. Sue) ?**

An artist makes a painting that is 12 feet by 9 feet. He paints a frame around the painting. The frame is 3 inches wide. What is the area of the frame? Please provide formula for figuring out. Answers (a)10.75ftsq(b)10.5ftsq (c)12.96ftsq(d)5.3125ftsq Thanks.

*December 1, 2012*

**Chemistry**

not much of a question but more of an appreciation, thanks for helping i was really confused before today

*November 30, 2012*

**Chemistry**

consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4). Calculate the pH after 0.10 mol of HCl has been added to the original solution. Assume no volume change on addition of HCl. Goes along with the last one i posted, i know i have to realize ...

*November 30, 2012*

**Chemistry**

never mind i understand where you were getting at thanks

*November 30, 2012*

**Chemistry**

do i have to account for the NaF, when plugging in the concentration for F^-. The reason im confused is because they are both weak in respect to their acidity and base that wont allow them to dissociate and i don't really know where to go from there

*November 30, 2012*

**Chemistry**

consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4), Calculate the pH of this solution

*November 30, 2012*

**Statistics**

I need to know how to find the probability that z0 is greater than or equal to 2.40 using my TI-83+. The answer is .008200, but I don't know how to get that using my calculator. The only reason I know the answer is because it is an example from my homework. Please help!

*November 29, 2012*

**Math**

How can I get 24 out of 2.4, 7.5, 1, and 6 using +, -, *, and/or /

*November 28, 2012*

**programming**

Using Raptor, create a condition loop that will ask the user for input of two numbers. The numbers should be added and the sum displayed. The loop should also ask the user if he or she wishes to enter two more numbers and perform the operation again, the response to the ...

*November 28, 2012*

**chemistry**

Naphthalene, commonly known as moth balls, is composed of 93.7% carbon and 6.3% hydrogen. determine the empirical for naphthalene. molecular formula for Naphthalene. Determine the number of empirical formulas you would need to make a full naphthalene molecule.

*November 28, 2012*

**chemistry**

Vanadium oxide is used as an industrial catalyst. The percent composition of this oxide is 56.0% vanadium and 44.0% oxygen. Determine the empirical formula for vanadium.

*November 28, 2012*

**calculus**

-24/25

*November 27, 2012*

**programming**

Develop psuedocode to control operation of vending machine The ACME Company has approached you with a request to develop the psuedocode that will control the operations of their new series of vending machines. The program will be required to maintain the product inventory and ...

*November 26, 2012*

**chemisrty**

how many liters of oxygen can be produced at stp from the decomp. of .25 liters of 3M H2O2 ACCORDING TO THE REACTION 2H2O-2 H2O+O2

*November 24, 2012*

**algebra**

(3a^4b+4ab^3)+(5ab^3-3a^4b

*November 21, 2012*

**Math - 8th grade - Please help**

I don't know the formula to figure this out. Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish...

*November 16, 2012*

**8th Grade math - Ms. Sue please**

An archaeologist has set up a dig at a newly discovered site. She and her team start excavating an area that is 36 feet by 24 feet. Because the scientists find many artifacts near the edges of this area, they decide to expand the dig. They add nine feet in all directions to ...

*November 16, 2012*

**8th grade math - Ms. Sue please**

Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish at the same time. How far does Charlie drive? ...

*November 16, 2012*

**physics**

.020m/s^2

*November 16, 2012*

**math**

Ms Sue, can you help please?

*November 16, 2012*

**math**

Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish at the same time. How far does Charlie drive? ...

*November 16, 2012*

**Math**

The area of a circus ring is about 1,385 square feet. What is the circumference of the ring?

*November 16, 2012*

**Math**

Franco is ordering lunch with a drink, sandwich, and a salad. He has a choice of 3 drinks, 2 sandwiches, and 4 salads. How many possible lunches are there? 3*2*4=24 lunches?

*November 16, 2012*

**Physics**

A baseball player throws a baseball up at 24.3 m/s. How long must he wait before he can catch the baseball on its way down?

*November 15, 2012*

**Math**

Explain how you can determine whether a system of two linear equations will be consisten, dependent, or inconsistent?

*November 15, 2012*

**chemistry**

CH3CH2CH=CHCH3 --KMnO4-> Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

*November 13, 2012*

**chemistry**

CH3CH2CHCHCH3 --HIO4-> | | HO OH Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

*November 13, 2012*

**chemistry**

CH3CH2CH=CHCH3 --KMnO4-> Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

*November 13, 2012*

**Chem**

Is this reaction endothermic or exothermic? Ca(C2H3O2)2(s) = Ca2+(aq) + 2C2H3O2-(aq)

*November 13, 2012*

**Social Studies**

Veterans day When did this first come about And who did do this What does this day mean to vets And what are some events that day

*November 11, 2012*

**Chemistry**

So is B correct, can someone explain

*November 8, 2012*

**Math**

Hi Bob - I have 4 possible answers and cannot arrive at any of them by the above. My choices are (a)634mph (b)1038mph (c)761mph (d)113mph

*November 7, 2012*

**Math**

The radius of Earth is 3,959 miles. A spacecraft orbits 6 miles above the surface of Earth. The spacecraft completes 220° of a revolution around Earth in one day. What is the average speed of the spacecraft?

*November 7, 2012*

**physics**

A 10.4 kg object oscillates at the end of a vertical spring that has a spring constant of 17500 N/m. The effect of air resistance is represented by the damping coefficient b = 3.00 N¡¤s/m.

*November 6, 2012*

**Chemistry**

A sample of hydrogen is collected over water at a total pressure of 648 mm Hg at 22 oC. The vapor pressure of water at 22 oC is 19.8 mm Hg. The partial pressure of the hydrogen is __________.

*November 6, 2012*

**Social studies**

Thank you Ms. Sue Anyone else have info to add to Ms. Sue's answer.

*November 3, 2012*

**Social studies**

Brief synopsis on the cause, effect and result Of the attack on Pearl Harbor. Six and one half Pages already typed and on cardboard made A flag, have pictures, just need alittle help In summarizing some facts you may have with The facts I have for the cardboard display Board. ...

*November 3, 2012*

**Geometry**

A museum was designed without windows, but a truncated cylindrical skylight lightens the building. In the development of this, the architect has areas where the angles formed at junctures are vertical angles. If a pair of vertical angles measures 5x - 54 and 3x -24, find the ...

*October 31, 2012*

**Algebra**

Tina's change of $1.35 consisted of quarters and dimes only and she received twice as many dimes as quarters. How many dimes were there?

*October 30, 2012*

**Algebra**

At its grand opening, the gutherie market distributed two different types of souvenirs. One type costs 20 centseach, and the other type costs 25 cents each. One thousand souvenirs were distributed in all. If the cost of these souvenirs was $220, how many of each type were ...

*October 30, 2012*

**Algebra**

The length of a rectangular playground exceeds twice its width by 25 meters, The perimeter of the playground is 650 meters. Find the demensions of the playground.

*October 30, 2012*

**Chemistry**

A sample weighing 3.064 g is a mixture of Fe2O3 (molar mass = 159.69) and Al2O3 (molar mass = 101.96). When heat and a stream of H2 gas is applied to the sample, the Fe2O3 reacts to form metallic Fe and H2O(g). The Al2O3 does not react. If the sample residue weighs 2.407 g, ...

*October 29, 2012*

**Physics**

A rocket of mass 1.0x10^3kg is being fired to a height of 5.0 x 10^3 m. The rocket engine shuts off when the rocket reaches a height of 1.0x10^3m, and the rocket coasts up to 5.0 x 10^3 m. A) What velocity must the rocket have at the 1.0x10^3 m point to enable it to reach 5.0 ...

*October 28, 2012*

**Math**

A local animal shelter had four more than six times as many adult cats as kittens. After eight of the kittens were adopted, the shelter had four fewer than eight times as many adult cats as kittens. How many adult cats are at the shelter?

*October 27, 2012*

**chemistry**

If a current of 5.0 Amps is passed through the electrolytic cell for .5 hour, how should you calculate the number of grams of bromine produced?

*October 26, 2012*

**Chemistry**

I took that answer (0.327 mmol) and divided it by 50ml to get my Molarity. But this does not seem correct. What am I doing wrong?

*October 25, 2012*

**Chemistry**

A 50.0 mL sample containing Cd2 and Mn2 was treated with 49.1 mL of 0.0700 M EDTA. Titration of the excess unreacted EDTA required 17.5 mL of 0.0300 M Ca2 . The Cd2 was displaced from EDTA by the addition of an excess of CN–. Titration of the newly freed EDTA required 10....

*October 25, 2012*