# Posts by anon

Total # Posts: 2,726

**Chemistry**

I know, that is why I am confused choosing an answer.

*March 26, 2017*

**Chemistry**

The following ions contain three oxygen atoms: A) carbonate, sulfite, and nitrite B) sulfite, nitrate, and bromate C) sulfate, hypochlorite, and carbonate D) chlorate, iodate, and phosphite I know I can eliminate A and C.

*March 26, 2017*

**Chem**

Calculate the standard enthalpy change for the reaction: 2C8H18(l) + 17O2(g) --> 16CO(g) + 18H2O(l) Given: 2C8H18(l) + 25O2(g) --> 16CO2(g) + 18H2O(l): ?Hº = -11,020 kJ/mol 2CO(g) + O2(g) --> 2CO2(g): ?Hº = -566.0 kJ/mol

*March 26, 2017*

**Chemistry**

Calculate the amount of heat necessary to raise the temperature of 12.0 g of water from 15.4ºC to 93ºC. The specific heat of water = 4.18 J/gºC. q = ms?T q = (12.0g) (4.18) (93.0 - 15.4) q = 3892.416 J ??

*March 26, 2017*

**Chemistry**

Potassium is a reactive element. Bromine is a reactive element. Write the complete balanced chemical equation using appropriate chemical symbols for the reaction when potassium reacts with bromine to make a solid product showing correct symbols and states of reactants and ...

*March 26, 2017*

**Chemistry**

The enthalpy of combustion of benzoic acid (C6H5CO2H) is –3228 kJ/mol. The burning of 1.698 g of benzoic acid in a calorimeter causes the temperature to increase by 2.865 ºC. What is the heat capacity (in kJ/ºC) of the calorimeter?

*March 25, 2017*

**Chemistry**

Given H2(g) + (1/2)O2(g) --> H2O, ?Hº = -286 kJ/mol, determine the standard enthalpy change for the reaction 2H2O(l) --> 2H2(g) + O2(g). Just checking... should end up with ?Hº = 572 kJ/mol right??

*March 25, 2017*

**Chemistry**

Given ?Hºrxn = -1670 kJ/mol for 2Al(s) + (3/2)O2(g) --> Al2O3(s), determine ?Hº for the reaction 2Al2O3(s) --> 4Al(s) + 3O2(g). I flipped Al(s) + (3/2)O2(g) --> Al2O3(s) to Al2O3(s) --> A(g) + (3/2)O2(s) and multiplied the molar values by 2. I ended up ...

*March 25, 2017*

**Chemistry**

Yes, I meant answer C.

*March 24, 2017*

**Chemistry**

Which of the following processes is endothermic? a) H2O (g) --> H2O (l) b) 3O2 (g) + 2CH3OH(g) --> 2CO2(g) + 2H2O(g) c) H2O (s) --> H2O (l) d) O2(g) + 2H2(g) --> 2H2O(g) I a guessing b, since energy has to go into the reaction for water to go from a solid to a ...

*March 24, 2017*

**physics**

Two small balls are attached to a rigid rod of mass 2.2 kg that is 6.0 m in length. The first ball has a mass of 2.25 kg and the second ball has a mass of 4.95 kg. (c) What is the moment of inertia of the rod when it spins around its center of mass?

*March 23, 2017*

**Chemistry**

So, essentially .6164 kJ/g --> kJ/mol .6165/24.31 = .0254 kJ/g

*March 23, 2017*

**Chemistry**

When .1625 g of Magnesium is burned in a bomb container that has a heat capacity of 3.03 kJ/ºC, the temperature increases by 1.252 ºC. How much heat (kJ/mol) is liberated during the burning of magnesium? Just want to make sure I am doing this correctly: q = ms?T q...

*March 23, 2017*

**Chemistry**

Calculate the enthalpy of formation if 78.5 g of carbon dioxide in the following reaction: C(s) + H2O(g) --> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + (1/2)O2(g): ?°f = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): ?°f = +84.7 kJ/mol c) 2CO2(g...

*March 23, 2017*

**Chemistry**

In which of the following reactions is work done by the system to the surroundings? A) 2CH3OH(l) + 3O2(g) --> 4H2O(l) + 2CO2(g) B) S(s, rhombic) + O2(g) --> SO2(g) C) 2AgNO3(s) --> 2AgNO2(s) + O2(g) D)4Fe(s) + 3O2(g) --> 2Fe2O3(s) My guess is B because according to...

*March 23, 2017*

**Chemistry**

Calculate the enthalpy of formation of carbon dioxide in the following reaction: C(s) + O2(g) -> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + 1/2 O2(g): ?H° = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): ?H° = +84.7 kJ/mol c) 2CO2(g) + 3O2(g) --&...

*March 22, 2017*

**Math**

Yes, this is what I thought!! Im so confused unless this is a trick question.

*March 22, 2017*

**Math**

Which of the following equivalences is true? x^2 ? 0 ? (x+1)^2 ? 1 x^2 ? 0 ? x^2+1 ? 1 x > 0 ? x^2 > 0 x^2 > 0 ? x^2+1 ? 1 x ? 0 ? x^2 ? 0

*March 22, 2017*

**Maths, dynamics**

A particle moves such that its velocity at time t is given by v =5t^5i + 4t^5j + t^3k. If its position x at time t = 0 is given by x ( 0 ) = i + 2j, what is the position of the particle at time t?

*March 21, 2017*

**Maths, dynamics**

A particle of mass 45 kg moves in a straight line such that the force (in Newtons) acting on it at time t (in seconds) is given by 225t^4-90 t^2-225. If at time t = 0 its velocity, v , is given by v ( 0 ) = 2, and its position x (in m) is given by x ( 0 ) = 5, what is the ...

*March 21, 2017*

**Social Studies**

C D A

*March 20, 2017*

**Chemistry**

The enthalpy of combustion of butane C4H10 is described by the reaction: C4H10(g) + (13/2) O2(g) -> 4CO2(g) + 5H2O(g) ?H°rxn = –2613 kJ/mol Given the following enthalpies of formation: ?H°f[CO2(g)] = -393.5 kJ/mol ?H°f[H2O(g)] = -241.8 kJ/mol Calculate the ...

*March 18, 2017*

**Chemistry**

What is the final temperature when 180.0 mL water at 101.3 C is added to 93.1 mL of water at 65.5 C?

*March 17, 2017*

**Chemistry**

A gas expands its volume from 4.7 L to 8.9 L at constant temperature. Answer the following: a) If the gas expands against vacuum conditions, calculate the work (in joules) done by the gas. b) Calculate the work done (in joules) by the gas if it expands against a constant ...

*March 17, 2017*

**World History**

Do you finish the test?

*March 15, 2017*

**Chemistry**

Which statement is always true if ?U sys is always negative? a) q = w b) +q>–w c) -w> +q d) +w>-q

*March 11, 2017*

**Chemistry**

Identify which of the following changes is exothermic. a) liquid water boils to steam b) liquid water freezes to give ice c) ice melts to give liquid water d) liquid water increases in temperature from 35 C to 45 C

*March 11, 2017*

**Chemistry**

what volume of oxygen is needed to react to complete reaction and to form 5cm of so3?

*March 11, 2017*

**Accounting Help (with answers for checking)**

Ben Guslists, vice-president of sales, has recommended adding a new product line. A market study and cost analysis show that the new line should yield the following annual results: New Sales $2,800,000.00 Cost of Sales $1,600,000.00 Operating Expenses $200,000.00 Total ...

*March 10, 2017*

**Algebra**

When kevin commuted to work one morning, his average speed was 45 mph. He averaged only 30 mph for the return trip because of an accident on the highway. If the total time for the round trip was 50 min determine the distance between his place of work and his home.

*March 6, 2017*

**Math **

the ratio of A to B is 3:8 and the ratio of B to C is 1:6 what is the ratio of A to C

*March 6, 2017*

**Chemistry**

Ross pours water at 6.0 C into a container with a pressure of 23. torr. He then boils the water to a temperature of 34 C. The volume changes to 18. mL and pressure to 78. torr. What was the initial volume of the water?

*March 6, 2017*

**Chemistry**

When a person got onto an airplane, she brought with her a half-full 1.0000 L aluminum water bottle that was closed inside the airport at standard pressure and a temperature of 26.000 C. After the plane takes off and climbs to 36,000. feet, the cabin pressure is at 0.82000 atm...

*March 6, 2017*

**Algebra **

For the equation -4y =8x what is the constant variation? -4 -2 1 2 Is it -2?

*March 5, 2017*

**Chemistry**

Which pair of reactants will not react? Au(s) with Hg^2+ (aq) Pt^2+ (aq) with Au(s) Ag(s) with Cu(s) Au(s) -> Au^3+(aq) + 3e- Hg(s) -> Hg^2+(aq) + e- Pt(s) -> Pt^2+(aq) + 2e- Cu(s) -> Cu^2+(aq) + 2e- My guess is all of them, but I am not entirely sure.

*March 5, 2017*

**Chemistry**

Using the following portion of the activity series for oxidation half-reactions, determine which element(s) can react with an acid to produce H2 gas. Co(s) ? Co^2+ (aq) + 2e- Ni(s) ? Ni^2+ (aq) + 2e ? Sn(s) ? Sn^2+(aq) + 2e - H2 (g) ? 2H+ (aq) + 2e ? Cu(s) ? Cu^2+ (aq) + 2e ? ...

*March 5, 2017*

**History**

That was really rude. I came on here because I just needed some help because my class is hard and I've read my materials. I will be giving this website a bad rating and never using it again. You could give me a link that I could read to help me understand everything but ...

*March 2, 2017*

**History **

Which type of rule allowed western governments to run colonies themselves? A: Direct rule B: indirect rule C: Sphere of influence D: protectorate I think it's c or d. I read my textbook but it all seems like they are under some type of government.

*March 2, 2017*

**math**

ahh

*March 1, 2017*

**math**

25 + 20 + 18 + 17 = 80 27 (2) seaters = 54 spots to sit. 80 students.. 54 spots to sit. :/ Not sure how that would work out

*March 1, 2017*

**math**

And std 1 , 2 ,3 and 4 are the different classrooms?

*March 1, 2017*

**math**

two*

*March 1, 2017*

**math**

What's "(2) seaters"? Is it something that seats too people? I'm confused..

*March 1, 2017*

**math**

30% of 5,000 is 1,500. 60% of the 1,500 kids are boys. That means 40% of 1,500 kids are girls. 40% of 1,500 is 600. There are 600 girls in the town.

*March 1, 2017*

**art**

Yes I agree.

*March 1, 2017*

**Math**

Does anyone have the answers for the Penn Foster Math for Business and Finance proctored exam? 060497

*February 28, 2017*

**health**

I think 1. is A and 2. is B or C So yeah I agree with you.. sadly I don't know between B and C either..

*February 27, 2017*

**social studies**

what was major cause of problems with the sharecropping system

*February 26, 2017*

**Trig identies, Calculus**

Use the identities cos^2 x + sin^2 x =1 and cos2x=cos^2 x -sin^2 x to show that cos^4 x -sin^4 x = cos2x Im not sure how, I can solve my problem with half angle identities but im not sure where to start with this.

*February 25, 2017*

**matrix, linear transformations**

To add this is the matrix multiplication im doing to get the answer: {{4,0},{0,6}}*{{0,1},{1,0}}*{{1,2},{0,1}

*February 25, 2017*

**matrix, linear transformations**

Morning, Bit confused: I have been given the following: g(x,y)=(4x,6y) h(x,y)=(x+2y,y) k(x,y)=(y,x) and ive got the following matrix for each of them: g={{4,0},{0,6}} h={{1,2},{0,1}} k={{0,1},{1,0}} So ive been asked to prove the linear transformation f=k.h.g has the matrix: A...

*February 25, 2017*

**Math Derivatives**

Find f''(2) of function f(x)=xsin(pi/x)

*February 22, 2017*

**math help asap**

For the data in the table does y vary directly with x? if it does write an equation for the dorect variation. x;y 10,15 16,24 20,30 a:yes; y=1.5x b:yes;y=2x c:yes;y=x+5 d: y does not vary directly with x if you are from connections and know any other answers/know to help with ...

*February 22, 2017*

**Differential equations,Calculus**

Thanks Steve.

*February 22, 2017*

**Differential equations,Calculus**

Just to add, by doing what I described above my answer for c would be the same value as for k (i.e 3.9 or 5/4pi) so my particular solution would be. t=k(-1/r)+5/4pi

*February 22, 2017*

**Differential equations,Calculus**

So I have the following differential equation. The general solution I have is: t=k(-1/r)+c I now need to find the particular solution when t=0 and the radius (r) = 1cm. So k is a constant which is approx 3.9 (5/4pi) So for the particular solution im really just plugging in the...

*February 22, 2017*

**Algebra**

1. The perimeter of a rectangle is 78 cm. The length is 3 greater than twice its width. Find the dimensions.

*February 21, 2017*

**chemistry**

Confused on how to find the reactants in these two compounds Ba(OH)2 (aq) + I2Zn (aq) -> ?? Additionally, I am not really sure how to find the ionic equation for this.

*February 21, 2017*

**Differential equation, calculus**

Thanks, just testing out methods and got carried away!

*February 21, 2017*

**Differential equation, calculus **

Hiya, Dt/dr =k/r^2 Is this directly solvable or do I need to separate variables. I've got t=-k/r+c from the former and something along the lines of r^3=kt+c from the latter. Think I'm doing it all wrong. Thanks

*February 21, 2017*

**Biology**

What is the path that electrons take in C3 photosynthesis?

*February 20, 2017*

**chemistry**

Balance the following chemical reaction and determine the number of moles of HI produced when 2.33 moles of H2(g) are consumed in the following chemical reaction: ___H2(g) + __I2(g) -> ___HI (g)

*February 19, 2017*

**Chemistry**

Hello, I was hoping that I could get some help with calculating the mass needed to completely react with this question. In the following chemical reaction between H2 and N2 to produce NH3, what is the mass of N2 needed to completely react with 0.65 g H2 to produce 3.68 g of ...

*February 19, 2017*

**Differential equation **

A spherical balloon remains spherical as it is slowly inflated. The radius of the balloon r (in cm) at time t (in seconds) satisfies the differential equation. Dr/dt = k/r^2 where k is a positive constant. When the radius is 3 cm, the radius is increasing at the rate of 5/36pi...

*February 19, 2017*

**social studies**

The World May Never Know: Thank you so much!

*February 15, 2017*

**Social Studies---Please Help!**

The answer is D

*February 8, 2017*

**Accounting**

Cupid Co. has total assets of $600,000 and its liabilities are equal to two-thirds of its total assets. What is the amount of Cupid Co.'s Owner's Equity? Please explain how you got this answer.

*February 7, 2017*

**Math - limits**

Let f(t)=sint where t is the measure of the angle in degrees. Thus f is the sin function on your calculator if you select degree mode. Then: lim(t->0)(f(t)/t)= (Your answer will be a real number.)

*February 7, 2017*

**History**

How did the issue of states' rights influence South Carolina's decision to secede? this is a short answer, so there are no options. please help. thanks in advance :)

*February 7, 2017*

**History**

How did the results of the presidential election in 1860 influence South Carolina's decision to secede? there are no choices, it is a short answer. please help :)

*February 7, 2017*

**Math**

Which ordered pair would be plotted by starting from the origin and moving 0.25 units left and then 3 units up? A) (3, -0.25) B) (0.25, -3) C) (-0.25,-3) D) (-0.25, 3)

*February 7, 2017*

**Math**

How do I shift f(x)=x^2+sinx 3 to the right and 7 up?

*January 31, 2017*

**Algebra**

Name a pair of complementary angles A- anglesign 1 and anglesign 4 B- anglesign 1 and anglesign 6 C- anglesign 3 and anglesign 4 D- anglesign 4 and anglesign 5 I think it's D

*January 30, 2017*

**american goverment check answers**

yup the answer is D. 2 is B and C and 3 is D btw :)

*January 27, 2017*

**Math**

Ah okay. Thanks!

*January 26, 2017*

**Math**

5!=120 1/120= 0.0083 but the options are 0.1 0.054 0.0167 Impossible to determine Am I missing something?

*January 26, 2017*

**Math**

5 students are randomly seated along the side of a table. What is the probability that they are seated in order of age?

*January 26, 2017*

**Math**

Ms. Sue read the question wrong. Set a variable for floor value. x*1.95=184.49 x=184.49/1.95

*January 26, 2017*

**Physics**

You drop a rock into a deep well. You can't see the bottom of the well but you can hear the impact after T seconds. Suppose the speed of sound is c feet per second and the depth of the falling rock at time t is gt^2/2 feet. Compute the depth d of the well. Your answer will...

*January 26, 2017*

**SS**

The correct answer was D from monarchy to democracy. I took the same quiz, the answers are: 1. A 2. C 3. A 4. D 5. D

*January 24, 2017*

**american goverment check answers**

1. A 2. C 3. C and D 4. C just took the quick check 100% :)

*January 23, 2017*

**math adv funcrions**

2sin5xcos4x-sinx=sin9x Can u do this without triple angle formula and how

*January 23, 2017*

**Social Studies**

You work for President Lula's government. You are most likely to support A) tax cuts for corporations.**** B) privatization of industry C) redirection of oil wealth to provide social services. D) budget cuts to education and health care

*January 22, 2017*

**Social Studies**

My textbook? My textbook is online and it didn't say anything about Roman Catholicism.

*January 22, 2017*

**Social Studies**

Brazil's culture reflects what unique aspect of its colonial history? A) its Roman Catholic missionary roots B) its ties to the West African slave trade C) its rule and settlement by the Portuguese D) its peaceful blending of native and European peoples

*January 22, 2017*

**Social Studies**

Okay thank you!

*January 21, 2017*

**Social Studies**

Wealth disparity in Brazil results mostly from? A)unequal land distribution.**** B)insufficient arable land. C)lack of oil and mineral resources. D)emphasis on cash crop exports.

*January 21, 2017*

**Physics**

A very long uniform line of charge has charge per unit length 3.70 µC/m and lies along the x-axis. A second long uniform line of charge has charge -2.20 µC/m per unit length and is parallel to the x-axis at y = 0.400 m. What is the net electric field (magnitude and...

*January 19, 2017*

**English**

i also just took it and "whatever"'s answers are correct.

*January 18, 2017*

**English**

can confirm these are 100%

*January 18, 2017*

**English**

Those answers above are right

*January 18, 2017*

**Geometry**

The base of a right triangular prism is a right isosceles triangle whose equal sides measure 25 cm each. The volume of the prism is 0.075 cubic meters. Find the height of the prism

*January 10, 2017*

**Social studies**

Nope Unknown is 100% correct Mrs.Sue looks like the prankster XD

*January 10, 2017*

**language arts**

@Cam'Ron KILL YOURSELF

*January 6, 2017*

**am I right ? or no?**

Which equations represent exponential growth? Which equations represent exponential decay? Drag the choices into the boxes to complete the table. Exponential Growth: y=4000(1.0825)^t ,y=12,000(0.72)^t , y=8000(0.97)^t , Exponential Decay: y=1700(1.25)^t , y=240(1/2)^t , y=1.5(...

*January 4, 2017*

**Algebra 1- Urgent**

The price of products may increase due to inflation and decrease due to depreciation. Derek is studying the change in the price of two products, A and B, over time. The price f(x), in dollars, of product A after x years is represented by the function below: f(x) = 0.69(1.03)x ...

*December 17, 2016*

**Algebra 1- Help please**

Belinda wants to invest $1000. The table below shows the value of her investment under two different options for three different years: Number of years 1 2 3 Option 1 (amount in dollars) 1100 1210 1331 Option 2 (amount in dollars) 1100 1200 1300 Part A: What type of function, ...

*December 17, 2016*

**Algebra 1 Please help**

f(n) = 8(1.05)^n, sorry

*December 17, 2016*

**Algebra 1 Please help**

A scientist is studying the growth of a particular species of plant. He writes the following equation to show the height of the plant f(n), in cm, after n days: f(n) = 8(1.05)n Part A: When the scientist concluded his study, the height of the plant was approximately 11.26 cm. ...

*December 17, 2016*

**calculus!**

use the definition of derivative to find d/dx(1/(3-x))

*December 16, 2016*