# Posts by Jack

Total # Posts: 1,823

**math**

32 times

**chemistry**

What is the standard heat of reaction (Delta H^0) for the decomposition of hydrogen peroxide? 2H2O2 (l) ==> 2H2O (l) + O2(g)

**Chemistry**

What is the standard heat of reaction (Delta H^0) for the decomposition of hydrogen peroxide? 2H2O2 (l) ==> 2H2O (l) + O2(g)

**physics**

An elevator cab in the New York Marriott Marquis has a mass of 4.96 x 103 kg and can carry a maximum load of 1.80 x 103 kg. If the cab is moving upward at full load at 3.71 m/s, what power is required of the force moving the cab to maintain that speed?

**physics**

A 0.077-kg arrow is fired horizontally. The bowstring exerts an average force of 50 N on the arrow over a distance of 0.75 m. With what speed does the arrow leave the bow?

**Chemistry**

Using calories, calculate how much heat 32.0g of water absorbs when it is heated from 25.0 degrees C to 80.0 degrees C. How many joules is this? Are these steps right? 32.0g x 55*C = 1760 calories = 420.65 Joules

**Chemistry**

Using calories, calculate how much heat 32.0g of water absorbs when it is heated from 25.0 degrees C to 80.0 degrees C. How many joules is this?

**Chemistry**

What Rght said

**Chemistry**

Using calories, calculate how much heat 32.0g of water absorbs when it is heated from 25.0 degrees C to 80.0 degrees C. How many joules is this?

**computers**

Microsoft Excel (full name Microsoft Office Excel) is a spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables and a macro programming language called VBA (Visual Basic for ...

**Chemistry**

But that's just .100 over .100 for the base over acid isn't it? then it would just be 6.4 X 10-5 because the log of 1 is 0?

**Trig**

The answer is -128+128i

**algebra**

the sum of

**Chemistry**

Which of the following compounds will melt ice at the lowest temperature? Sucrose, sodium chloride, or magnesium chloride?

**Chemistry**

Answer the following question about copper (II) sulfate pentahydrate: a)how much water (in g) is there in 10.0 g of the compound listed above? b)If you needed 2.50g of CuSO4 for a reaction but only had CuSO4 * 5H2O available, how many g would you need to use to get the same ...

**Chemistry**

A)250 g of LiBr is dissolved in 200g of water 100 degrees C. The solution is then cooled to 20 degrees C. How much precipitate (if any) is formed? B) 42 g of KCl is dissolved in 100g of water at 50 degrees C. The solution is then cooled to 20 degrees C. How much precipitate (...

**Global History**

What were the differing politucal and economic systems between the US and Soviet Union that helped lead to the Cold War? I know that the political difference was that the US was democratic and the Soviet Union were communists. However, if the US economic system was ...

**chemistry**

What is the freezing point of each solution? a)1.40mol Na2SO4 in 1750 g H2O Are these the right steps? 1.40mol Na2SO4 / 1.75kg = .8m 3 * 1.86 degrees C * .8m = 4.46 degrees C 4.46 degrees C - 1.86 degrees C = 2.6 degrees C

**Chemistry**

Determine the freezing points of each 0.20m aqueous solution. a)K2SO4 b)CsNO3 c)Al(NO3)3

**Chemistry**

What is the freezing point of each solution? a)1.40mol Na2SO4 in 1750 g H2O b)0.060 mol MgSO4 in 100g H2O

**math algebra with pizzazz**

pg 142 What happened to the computer programer

**Chemistry**

How many grams of K2SO4 would you need to prepare 1500 g of 5.0% K2SO4 (m/m) solution?

**Kindergarten Math**

A counter is a small plastic circle about a half-inch in diamiter

**grade 10 career studies**

I have to hand in an assignment called WHO AM I? for my grade 10 career studies course, i just need to no what to hand in exactly

**Osciallations**

A harmonic oscillator has mass 0.530km and an ideal spring with force constant 146N/m . Find the period, frequency, and angular frequency.

**Trig**

oh it's tan(x/2) = a ........... use the fact that x = 2 . x/2

**Trig**

Given that tan(pi/2) = a. Express tan(x) and sin(x) in terms of a. Hint: Use the fact that x = 2.(pi/2)

**Chemistry**

Which of the following substances dissolve to a significant extent in water? Explain your answer in terms of polarity. a) CH4 b) KCL c)He d)MgSO4 e)sucrose f)NaHCO3

**PRE CAL SEQUENCES**

Given the following finite sum 1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+....+1/(n(n+1)) a) Find the first 5 partial sums b) Make a conjecture for a formula for the sum of the first n terms c) Use mathematical induction to prove your formula

**Accounting**

The cost principle requires that when assets are acquired, they be recorded at

**Chemistry**

The molecules water (H2O) and methane (CH4) have similar masses, but methane changes from a gas to liquid at -161 degrees C. Water becomes a gas at 100 degrees C. what could account for the difference?

**math**

4(9.75h-3)=150 39h-12=150 39h=162 h=162/ 39=4.15, which means they can Afford to rent for 4 hours. This is for part (A)

**English**

the answer is do it yourself and stop trying to get it without studying you lazy ass.

**Social Studies**

What happened to Andrew Jackson when he was eight years old?

**Chemistry**

In a reaction chamber, 3.0mol of aluminum is mixed with 5.3mol Cl2 and reacts. The reaction is described by the following balanced chemical equation. 2Al + 3Cl2 ==> 2AlCl3 a)Identify the limiting reagent for the reaction. b)Calculate the number of moles or products formed c...

**Web application development JSP**

I would suggest that you go to a programming forum and ask for assistance there. I'm sure you will have more luck. Considering most helpers here are not proficient in programming. Good Luck!

**Physics**

A particle is moving along the x-axis subject to the potential energy function U(x) = 1/ x + x2 + x – 1. Determine the x-component of the net force on the particle at the coordinate x = 3.57 m

**chemistry**

If 7.24 kJ of heat is applied to a 952 g block of metal, the temperature increases by 10.7 degrees Celsius. Calculate the specific heat capacity of the metal in J/g degrees Celsius.

**Chemistry**

Write the 12 mole ratios that can be derived from the equations for the combustion of isopropyl alcohol. 2 C3H7OH(l) + 9 O2(g) ==> 6 CO2(g) + 8 H2O (g)

**Physics**

img242.imageshack.us/img242/9452/words.jpg That should be the image.

**Physics**

Hi, I've been having issues with solving this problem. Could anyone help? Two blocks, of masses M = 2.0 kg and 2M are connected to a spring of spring constant k = 215 N/m that has one end fixed, as shown in the figure below. The horizontal surface and the pulley are ...

**Chemistry**

Is 2HCl soluble in water? Is BaSO4 soluble in water?

**Chemistry**

Identify the precipitate formed when solutions of these compounds are mixed. H2SO4 + BaCl2 ==> So when you do the double replacement reaction, would the products of this chemical equation be HCl + BaSO4? or H2Cl2 + BaSO4 ? (not balanced) also would both of the products be ...

**Chemistry**

How do you balance Al(OH)3 --> Al2O3 + H2O Why does the OH decompose into O3 and H2O??

**Chemistry**

Classify each reaction and balance the equations. Al(OH)3 ==> Al2O3 + H2O

**Chemistry**

Complete and balance this decomposition reaction HI ==> is this reaction HI ==> H + I ? or... HI ==> H2 + I2 ? why?

**Chemistry**

Complete and balance this equation for a combination reaction. Be + O2 ==> Would it be Be + O2 ==> BeO2 ? or... 2Be + O2 ==> 2BeO ? Why??

**science**

okay after the diver jumps foward from the diving board,the force of gravity will accelerate the diver PARALLEL to the direction of motion , is the uppercase true or false?

**Physics**

An electric field exerts a force of 3.00 E-4 N on a positive test charge of 7.20 E-4 C. The magnitude of the field at the location of the charge is?

**Math**

sweet, thanks for the help guys, gonna win now.

**Chemistry**

Solid aluminum carbonate decomposes to form solid aluminum oxide and carbon dioxide gas. Is Al2(CO3)3 ==> Al2O3 + CO2 the right equation? If so, how do you balance this equation?

**Chemistry**

Balance the following equations. A) SO2 + O2 --> SO3 B)Fe2O3 + H2 --> Fe +H2O C)P + O2 -->P4O10 D)Al + N2 --> AlN

**Chemistry**

Write and balance equations for the following reactions. A)Iron metal and Chlorine gas react to form solid iron(III) chloride. B)Solid aluminum carbonate decomposes to form solid aluminum oxide and carbon dioxide gas. C)Solid magnesium reacts with aqueous silver nitrate to ...

**chemistry**

Write Skeleton equations for these reactions. A) Heating Copper(II) sulfide in the Presence of diatomic oxygen produces pure copper and sulfur dioxide gas. B)When heated, baking soda (Sodium hydrogen carbonate) decomposes to form the products sodium carbonate, carbon dioxide, ...

**bcc**

if you put honey,water,dishwashing liquid and vegetable oil in a clear jar and then you add asmall of plastic cup, plastic fork, straw and a small piece of styrofoam cup.

**bcc**

how do you work equation dealing friction and newtons when pulling the distance of a block

**Music**

tell me about the rocks band

**Chemistry**

which has the highest lattice energy BaO or SrO

**chemistry**

Compound A contains 1.75g nitrogen and 3.99g oxygen. Compound B contains 19.6g nitrogen and 56.0g oxygen. Are compounds A and B the same? Explain.

**chemistry**

Find the molar mass of Chromium (III) Hydrogen Phosphate. Also, what is the chemical formula for this molecule?

**chemistry**

The mass of twenty-three dozen pencils is 1.496 kg. What is the mass of 1 pencil?

**chemistry**

How many neon atoms are there in five moles?

**chemistry**

How many carbon atoms are there in 150.0 g Glucose? (Glucose is C6H12O6, molar mass = 180.16 g/mol)

**chemistry**

Convert 12 fluid ounces liters. (1 fl. oz = 29.57 cm^3)

**chemistry**

Which of the following are empirical formulas? A) Ribose (C5H10O5) B) Ethyl Butyrate (C6H12O2) C) Chlorophyll (C55H72MgN4O5) D) DEET (C12H17ON) (numbers are subscripts)

**ecology**

examples of how humans have increased their food supply and what effects these methods have on the environment overall.

**chemistry**

How many grams of oxygen are there in 100.0 grams of water? What percentage of the mass of water is oxygen?

**chemistry**

Find the number of K atoms, C atoms, and O atoms in 95.5g of K2Cr2O7. (Potassium 2, Chromium 2, Oxygen 7).

**English**

they seem good to me

**chemistry**

consider the reaction in which 410 grams of Ca(NO3)2 react with just the right amount of lithium metal in a single replacement reaction. 1-how many grams of lithium are required? 2- how many grams of each product can be produced?

**math**

i have 78% in the course the exam is worth 30% and i got 65% what is my overall mark in the course

**math**

i have 78% in the course the exam is worth 30% and i got 65% what is my overall mark in the course

**math**

a trianglar course for a sailing race is marked off by buoys. The first lef is 250 meters longer than the second and the third leg is 100 meters shorter then the first. if the length of the course is 2500 meters, find the length of each length

**math**

the first side of a triangle is 8 meters longer than the second side. the third side is 3 times the second side. the perimeter is 128 meters. find the lengths of the three sides.

**chemistry**

The vapor pressure of dichloromethane, CH_2Cl_2, at 0 degrees celcius is 134 mmHg. The normal boiling point of dichloromethane is 40 degrees celcius. Calculate its molar heat of vaporization (in kJ/mol).

**History**

sue's answer doesnt help at all. thanks alot i failed

**History**

All of the following account for nativist sentiment against the New immigrants of the late 19th century EXCEPT that the immigrants a. practiced different religions b. had different languages and cultures c. were willing to work for lower wages than were native born workers d. ...

**science**

I added 40 mL of NaOH 1N to rise the pH of 10g teriphitalic acid from 5.3 to 6.3, so if I adde the same 40 mL of NaOH to 12g of the same acid what is the new pH will I have?

**science**

why does magnesium dissolve quicker in strong acid

**Physics**

Oop's, my bust. It's 60 Joules. I believe the 50m was thrown is a curve to throw me off, as as the '60J' = W. Otherwise it would have been say '60N over 50m = 3000J'. Thanks guys.

**Physics**

A car with a mass of 100 kg, with initial v = 1 m/s, has 60 Joules of energy added for 50 m. What is the final velocty? I'm using KE = 1/2 mv^2 to find initial KE. Then add 600 J to this for the final KE. Thus, W = KFf - KEi; KEf = W + KEi and KEf = 1/2mv^2 v^2 = (2(KEf))/m

**9th grade**

an egyptian form of writing

**Math**

How do you divide whole numbers?

**Math**

how do i compute a problem like 4/7 * 2/3 * 6

**Algebra**

15=2(9+4)+3

**math**

DQ sells 6 times as many orders of french fries as sonic everyday. If both sold 60 more orders DQ would only sell 3 times as many fries. How many do each sell before and after the incease?

**Pre-Cal**

Find the exact value of sec 60°tan135°-cot60°sin60°

**math**

The sweater shop projected income this year will be 69,000. That amount represents 40% of the shops annual sales. What is the shops projected sales

**math**

If I gross 2645.00 and taxed 31% how much do I bring home?

**math**

a wagon retails for 49.97 the store receives a built in 40% profit margin what is the cost

**math**

I can buy office supplies @ walmart with a 30/10 chain discount. If I paid $47.25 for adding machine. What was the regular price of my purchase? 30/10 chain discount means .70 x .90

**math**

I can buy office supplies @ walmart with a 30/10 chain discount. If I paid $47.25 for adding machine. What was the regular price of my purchase?

**solve for unknown**

thank you

**solve for unknown**

If jack does home improvment and price the material ,add 1 and 1/2 times that amount for labor and then quotes the job. If he gets the job for 17,000 how much is the material? and labor ?

**math**

wagons retail for $49.97. stores receive the wagons with a 40% profit margin. what is the cost?

**French**

What does conduissez mean in french?

**math**

Mr. Havel bought a car for $2400 and sold it for $2700. what was the percent of profit for Mr. Havel in selling the car?

**health**

for the health i get very good but my head alwas hrt so how do i do i don't know tell me why

**physics**

31^2+67^2=5186 sqrt(5186)=72.01388 ANSWER =72.01388

**science**

How does the portuguese man of war contribute to science?