Monday

November 30, 2015
Total # Posts: 822

**precal**

Given an initial value of 17 g, which is halving once each 32 hours, an exponential function in term of hour t which models this situation is ...?
*June 12, 2011*

**Chemistry**

Alright thanks so much.
*June 7, 2011*

**Chemistry**

How many mL of concentrated HCl(aq) (36% HCL by mass, d=1.18g/mL_ are required to produce 12.5 L of a solution with ph = 2.10? First I started with finding out the concentration of [H30+] and for that I got 7.94 x 10^-3 but I don't know how to continue.
*June 7, 2011*

**Chemistry**

Thanks so much. I did that and I used 751 for P, .205L for V, 0.08206 for R and 296 K for T and I got 6.34 moles. When I substituted that into the formula for M = moles/L I got 30.9 but the actual answer that is written in my textbook is 1.96 x 10^-3 M.
*June 7, 2011*

**Chemistry**

What is [H30+] in a solution obtained by dissolving 205mL HCl(g), measured at 23 C and 751mmHg, in 4.25L of aqueous solution?
*June 7, 2011*

**math**

You receive an invoice for $565.00 with terms 3/10, net 30. If you pay it immediately, how much will you pay? A. $548.05 B. $551.25 C. $558.05 D. $559.95
*June 3, 2011*

**Chemistry**

Okay I think I figured out how to do it all. Thanks for explaining.
*May 28, 2011*

**Chemistry**

No I wasn't, but can I just use the pressure formula of P() = nRT/V and then just add all of them together?
*May 28, 2011*

**Chemistry**

Sorry my ICE table came out wrong. It is actually suppose to be 2SO3 <-> 2SO + 02 I 0 .100 .100 C 0 .1- 0.0916 .1-.0458 E 0.0916 .0084 .0542
*May 28, 2011*

**Chemistry**

0.100 mol of SO2 and 0.100 mol of O2 are introduced in a flask of 1.52 L. When in equilibrium, 203 is found to be 0.0916 mol. Determine kp. 2S03(g) <-> 2SO(g) + O2(g) In order to solve this question 1st I made an ICE table and I got the values 2SO3 <-> 2SO + 02 I ....
*May 28, 2011*

**math**

How many real number solutions exist for 2x2 8x 8 = 0?
*May 28, 2011*

**Chemistry**

Thanks so much for your help.
*May 28, 2011*

**Chemistry**

Hi. Thanks for your help. So this is how I solved the equation. 2NO2(g) <-> 2NO(g) + O2(g) Since the 2NO2 is reversed from the 1st equation, I got (1/7.5x10^2) and then since the 2NO(g) and the O2(g) are doubled from the 1st equation I got (7.5x10^2)^2 for 2NO(g) and the...
*May 28, 2011*

**Chemistry**

Given the equation NO(g) + 1/2)O^2(g) <-> NO(g) at 457 Kelvin with a K = 7.5 x 10^2 Find the K value for the equation 2NO^2(g) <-> 2NO(g) + O(g)
*May 28, 2011*

**Chemistry**

Oh okay, thank you so much for your whole explanation. I finally understand the whole concept behind it and what we are suppose to do. Thanks so much again :)
*May 28, 2011*

**Chemistry**

Yeah I did all the previous things to find Kc and I got kc = 0.012. But you know how for to get the other kc you said I would have to do 1/sqrt Kc, I know that I would do that because the product is H2S and I would do the inverse because it is reversed and I would sqrt because...
*May 28, 2011*

**Chemistry**

So instead of looking at each compound in the equation you would only look at the product side of it and compare it to the other equation and only either square,square root etc. that value?
*May 28, 2011*

**Chemistry**

Given the equation 2H^2S(g) <-> 2H^2(g) + S^2(g) With a Kp = 1.2x10^-2 at 1338 Kelvin Find the value of Kc for the reaction H^2(g) + 1/2S^2(g) <-> H^2S(g) at 1338 Kelvin
*May 28, 2011*

**Chemistry**

Ok this helps so much. Thanks a lot I appreciate it.
*May 25, 2011*

**Chemistry**

Ok thanks so much. So when I solve for X I got 4.48(0.086 - x) = x^2 0.385 - 4.48x - x^2 = 0 Now i'd substitute that into the quadratic formula? Or is there an easier way to solve for X?
*May 25, 2011*

**Chemistry**

Okay thanks so much.
*May 25, 2011*

**Chemistry**

When I am solving for X my formula comes out to be 4.84 = X^2/ (.186-X) Can I assume that x << .05 and eliminate it from the denominator and just solve for the equation 4.84 = X^2/.186?
*May 25, 2011*

**Chemistry**

HCONH2(g) <-> NH3(g) + CO2(g) Kc= 4.84 at 400 K2(g) If 0.186 mol of HCONH2(g) dissciates in 2.16L at 400K, what will be the total pressure at equilibrium?
*May 25, 2011*

**Chemistry**

OK thanks so much, I appreciate it.
*May 25, 2011*

**Chemistry**

When I converted everything I got 1.2x10^3 = (0.02 + x) / (0.12 - x)(x) = (0.02 + x) / (0.12x - x^2) 1.2x10^3(0.12x - x^2) = 0.02 + x 144x - 1.2x10^3x^2 = 0.02 + x Then I brought x to the other side and I got 145x - 1.2x10^3x^2 = 0.02 Then I get confused with the x's and ...
*May 25, 2011*

**Chemistry**

Starting with 0.3500mol Co(g) and 0.05500mol COCL2(g) in a 3.050 L flask at 668K, how many moles of Cl2 are present at equilibrium? Co(g) = Cl2(g) <-> COCL2(g) Kc = 1.2x10^3
*May 25, 2011*

**Chemistry**

Thank you so much. I got 9.7 x 10^-16. The answer is correct. I was just confused because why did we only substitute the k values for 2 compounds in the equation rather then all 4?
*May 25, 2011*

**Chemistry**

Determine Kc for the following reaction: 1/2N2(g) + 1/2O2(g)+ 1/2Br(g) <-> NOBr(g) from the following information (at 298K) 2No(g) <-> N2(g) + O2(g) Kc = 2.1x10^30 NO(g) + 1/2Br2(g) <-> NOBr(g) Kc = 1.4
*May 25, 2011*

**math**

how do you use the numbers 4, 5, 9, 7, and 21 to get the number 23 (using it in a number sentence) i cannot get it and its driving me crazy! please help
*May 17, 2011*

**Chemistry**

The Hydrolysis Reactions - Write net-ionic equations for the reaction of each salt with water below. If there is no reaction, write N.R. 1. NH4C2H3O2 2. NH4Cl 3. NaCl 4. Na2CO3 5. NaC2H3O2 6. NaHSO4 7. FeCl3 8. NaH2PO4 9. NaHCO3
*April 30, 2011*

**math**

yeah in some cases if you really truley need it,like maybe if your dealing with decimals
*April 28, 2011*

**algebra**

explain why a solution of a word problem should be checked using the original wording of the problem and not the equation written from the wording
*April 12, 2011*

**math**

8x+16÷x^(2)-1 . x+1÷4x+8
*March 30, 2011*

**physics**

It takes 15 seconds for a wave to pass a buoy 25 meters from shore. If its wavelength is 30 meters, what is its speed.
*March 30, 2011*

**Chemistry**

Titration of an Unknown Acid... What effect on the molar mass of the unknown acid would each of the following have... Would it make the calculated molar mass high, low, or would it have no effect? 1. Adding 5 drops of phenolphthalein instead of 1 drop... Answer: No effect. 2. ...
*March 26, 2011*

**Chemistry**

Would it be better to use an unknown acid sample of a size that should require 10.00 milliliters or one that would require 15.00 milliliters of titrant? Explain. I have been thinking about this question... And I don't believe it matters what measurement of milliliters is ...
*March 26, 2011*

**Chemistry**

Thank you.
*March 26, 2011*

**Chemistry**

Why is it important to swirl the NaOH solution each time before using it during a titration?
*March 26, 2011*

**physics**

Two electrostatic point charges of +30 ìC and +25 ìC exert a repulsive force of 200 N on each other. What is the distance between the two charges?
*March 25, 2011*

**Math**

A right square pyramid’s base has edges measuring 20 feet each. If the pyramid’s height is 27 feet, what is its volume, in cubic feet?* *Could you include an explanation as well?
*March 15, 2011*

**Chemistry**

The freezing point of a cyclohexane sample is 6.20*C. A soltuion is prepared by dissolving 0.4660g of an unknown solute in 36.0g cyclohexane. The freezing point of the solution if 4.11*C. Calculate the molar mass of the unknown solute. Kf for cyclohexane is 20.0*Ckg/mole.
*March 14, 2011*

**earth science**

how does the apparent diameter of the sun from earth affect the orbital velocity?
*March 14, 2011*

**physics**

how much should a ramp rise over 10 meters of run for an angle of 12 degrees
*March 10, 2011*

**Calculus**

D) 54 One vertex is x,y and the other is -x,y y= 27 - x^2 A= 1/2 BxH B = x - -x = 2x H = 27 - x^2 A = 1/2 * 2x * (27 - x^2) Take the derivative, find when the derivative is = 0 then plug that back in to get dimensions and solve for area.
*March 8, 2011*

**Chemistry**

What are 3 possible reasons why a percentage recovery might be low? And what are 3 possible reasons why a percentage recovery might be well over 100%?
*March 6, 2011*

**Chemistry**

Iron is obtained from iron ore according to the following reaction: Fe2O3+CO---> Fe+CO2 (unbalanced). a. Assuming the blast furnace is 90.0% efficient in recovering the iron, what is the actual mass of iron obtainable from a ton of ore? b. What is theoretical yield of iron ...
*March 6, 2011*

**Chemistry**

How many milliliters of 3.0 M NaOH are required to react with 0.50g of Cu2+ to form Cu(OH)2?
*March 6, 2011*

**Chemistry**

How many milliliters of 3.0 M NaOH are required to react with 4.0mL of 16.0 M HNO3? ---> Not sure if I am solving correctly but I keep getting 21mL.
*March 6, 2011*

**French - Help :(**

Hi all. I'm trying to write a paragraph in french. These are my instructions: Décrivez vos activités habituelles pendant les vacances dernières en utilisant au moins sex verbes réfléchis à l'imparfait. This is what I want to ...
*March 1, 2011*

**geometry**

The width will be 6 in.
*February 17, 2011*

**Math**

4/13 is cause 4*3 is 12 so thats the close you gonna get so the answer is 31
*February 14, 2011*

**Chemistry**

A 0.188g sample of unknown metal, X (s), produced 71.4 ml of hydrogen gas when reacted with HCL according to the equation: X(s)+2HCL(aq)--->XCl2(aq)+H2(g) The gas was collected over water at 23 degrees Celsius. The levels of water inside and outside the gas collecting tube ...
*February 10, 2011*

**Chemistry**

A 0.0677g sample of magnesium metal reacted with excess hydrochloric acid to produce 69.9 ml of hydrogen gas. The gas was collected over water at 21.0 degrees Celsius. The levels of water inside and outside the gas collecting tube is identical. The water vapor pressure at 21.0...
*February 10, 2011*

**Chemistry**

A sample of oxygen gas is collected by displacing water from an inverted bottle as shown in the diagram below. The volume of O2(g) collected is 400.0ml at 25 degree Celsius. The atmospheric pressure is 680 torr and the vapor pressure of water at 25 degree Celsius is 23.8 torr...
*February 3, 2011*

**Chemistry**

CaO(s) reacts with SO2(g) according to the following equations: CaO9(s)+So2(g)--> CaSO3(g). A 8.85g mixture containing CaO(s) is placed in a 3.00-L container. The container is filled with SO2(g) to a pressure of 749 torr, at 20.0 degree Celsius. After the reaction has gone ...
*February 3, 2011*

**Chemistry**

Consider the flasks diagrammed below. What is the total pressure in torr after the stopcock between the two flasks is opened? He(g)---> V=1.25L and P=0.300atm and Ar(g)---> V=2.50L and P=233 torr.
*February 3, 2011*

**Chemistry**

A steel cylinder contains 98.0 moles of oxygen gas at temperature of 38 degree Celsius and a pressure of 740 torr. After some of the oxygen gas has been used, the pressure is reduced to 332 torr at a temperature of 24 degree Celsius. What mass of oxygen gas is removed from the...
*February 3, 2011*

**Chemistry**

A compound contains only hydrogen and nitrogen and is 12.6% hydrogen by mass. A gaseous sample of the compound has density of 0.925g/L at 690 torr and 110 degree Celsius. What is the molecular formula of the compound?
*February 3, 2011*

**Math**

The graphs of y= x^2 - 8x - 35 and y= -2(x^2) + 16x +3 intersect in two points. What is the sum of the x-coordinates of the two points of intersection?
*February 2, 2011*

**Math**

How many non-congruent triangles with only integer side legnths have a perimeter of 15 units?
*February 2, 2011*

**Math**

There is a 4 x 4 square grid. Two unit squares are chosen from the 16 unit squares possible. What is the probability that they do NOT have a vertex in common? Express your answer as a common fraction.
*February 2, 2011*

**Math**

There is a 4 x 4 square grid. Two unit squares are chosen from the 16 unit squares possible. What is the probability that they do NOT have a vertex in common? Express your answer as a common fraction.
*February 2, 2011*

**algebra**

4.42 hrs. 1/7 +1/12 = 19/84 84/19= 4.42...
*February 2, 2011*

**Math**

When x^2-5x+3c is divided by x-3 the remainder is -12. What is the value of c?
*February 2, 2011*

**Math**

How many unit cubes would it take to construct the complete exterior of a hollow cube with edges of 4 units and faces 1 unit thick?
*February 2, 2011*

**Chemistry**

Concentrated sulfuric acid is 18.4 molar and has a density of 1.84 grams per milliliter. After dilution with water to 5.20 molar the solution has a density of 1.38 grams per milliliter. This concentration of H2SO4 is often used in lead storage batteries(like a car battery). 1....
*January 13, 2011*

**Chemistry**

Thank you.
*January 11, 2011*

**Chemistry**

The grams of oxygen that would produce 13.4 g Cl^2O^7 molecules.
*January 11, 2011*

**Math**

Can u (C) it? Start w/ (x) next is (x +2) next is (x + 4)
*January 9, 2011*

**Math**

This is a proportion problem. There are two ways to solve this. The 1st way, my preferred one, is to take 6 and 10 as a ratio. 6:10 simplyfied is 3:5. So, 45 / 5 is equal to 9, so 3 * 9 = 27. That may be a little confusing sometimes so there is a second way. Take 6/10. It is ...
*January 9, 2011*

**Math**

How many five-digit integers are perfect squares?
*January 9, 2011*

**algebra**

if the length is 7 meters longer than its width. what is the width of the object if the perimeter is equal to 98
*January 6, 2011*

**Math**

How did the Hunter get hurt while benind over to study some tracks? Algebra with Pizzazz! pg 123 OBJECTIVE: to divide a polynomial by a binomial EX: (x^2+8x+150/(x+5)
*January 2, 2011*

**Child day care managment**

A childs ability to jumb for distance is an example of ? a. agility b. flexibility c. explosive power d. reaction time my answer is c what you think? The most important consideration when installing playground equipment is ? a. cost b. height c. finishing materials d. surface ...
*December 29, 2010*

**algebra**

find the illegal values of c in the multiplication statement c^2-3c-10/c^2+5c-14.c^2-c-2/c^2-2c-15
*December 17, 2010*

**Trig**

An airplane is flying on a compass heading (bearing) of 340 degrees at 325 mph. A wind is blowing with the bearing 320 degrees at 40 mph. Find the component form of the velocity of the airplane. then find the actual ground speed and direction of the plane
*December 17, 2010*

**ALGEBRAIC FRACTIONS**

find the illegal values of C in the multiplication statement c^2-3c-10/c^2+5c-14 . c^2-c-2/c^2-2c-15
*December 12, 2010*

**algebra**

multiply r^2+7r+10/3 by 3r-30/r^2-5r-50
*December 11, 2010*

**ALGEBRA**

multiply r^2+7r+10/3 by 3r-30/r^2-5r-50
*December 11, 2010*

**ALGEBRA**

divide 40x/64y by 5x/8y
*December 11, 2010*

**ALGEBRA**

divide m^2n^3/p^3 by mp/n^2
*December 11, 2010*

**algebra**

reduce the fraction 6x/12x to lowest terms
*December 8, 2010*

**algebra**

1/2 right
*December 8, 2010*

**algebra**

reduce the fraction 6x/12x to lowest terms.
*December 8, 2010*

**9th grade geometry**

bisector
*December 2, 2010*

**chemistry**

I completely understand Le Chateliers principle but I have no idea about these questions. They're due tomorrow so fast help would be appreciated. Why did adding water to the equilibrium involving CoCl_4_^2-^ cause the color to change? Use Le Chateliers principle to explain...
*December 1, 2010*

**Chemistry**

-69
*December 1, 2010*

**Calculas**

2.oo6
*December 1, 2010*

**Calculus - MathMate Please help**

nope, you are wrong. I got the correct answer. area1 and area2 are not equal to each other since their limits are DIFFERENT. for area1, the limits should be (from 0 to c/2) and for area2. the limits should be (from pi/2+c to pi). by solving it i got the value for c. Thank you ...
*November 29, 2010*

**Calculus - MathMate Please help**

ok, i tried to do what you told me but i cant solve it for c because they cancel each others out! the integral for the first one i got is [sin(c)cos(x)-cos(c)sin(x)+sin(x)+c] and the integral for the 2nd one i got is [-sin(c)cos(x)+cos(c)sin(x)-sin(x)+c] I dont know what to do...
*November 29, 2010*

**Calculus - MathMate Please help**

I got two areas but i cant solve it for c because they cancel each others out!!! the integral for the first one i got is [sin(c)cos(x)-cos(c)sin(x)+sin(x)+c] and the integral for the 2nd one i got is [-sin(c)cos(x)+cos(c)sin(x)-sin(x)+c] I dont know what to do from here. can u...
*November 29, 2010*

**Calculus - MathMate Please help**

Thank You. I think i got the idea. i will try to solve it.
*November 29, 2010*

**Calculus - MathMate Please help**

I asked this question on last thursday and u told me that the bottom limit for the 1st and the right limit for the 2nd area is missing? The question that i posted had no other information and i dont know why you said that the limits are missing. There is no other limits that ...
*November 29, 2010*

**Calculus - please help!**

yes, ¥ðstands for pi. The quesiton that i wrote above is all information that are given. There is no other limit on this integration. I will wrote the question once again. Please help. Thank You. Suppose that 0 < c < pi/2. For what value of c is the area of the ...
*November 25, 2010*

**Calculus - please help!**

Suppose that 0 < c < ¥ð/2. For what value of c is the area of the region enclosed by the curves y = cos x, y = cos(x - c), and x = 0 equal to the area of the region enclosed by the curves y = cos(x - c), x = ¥ð, and y = 0? i have no idea how to solve this...
*November 25, 2010*

**Chemistry**

How many air molecules are in a \rm 12.0 \times 12.0 \times 10.0~ft room? Assume atmospheric pressure of 1.00 \rm atm, a room temperature of 20.0 \rm {}^{\circ}C, and ideal behavior. Volume conversion:There are 28.2 liters in one cubic foot
*November 16, 2010*

**math**

A full container holds 5/8 of a gallon of liquid. If the container is 4/5 full, how much liquid is in the container? I need answer to problem and how you solved it using words for the explanation.
*November 14, 2010*

**algebra**

f-g/1 = g/1 How can I make g the subject?
*November 1, 2010*

**maths**

A bond with face value of $500 redeemable at par in 13 years time, is paying interest at j2 = 9.0%. Find the purchase price of the bond to give a yield to maturity of j2 = 8.4%.
*October 26, 2010*

**9th grade**

In the odyssey, what is book 16, 17, 21, 22, and 23 about in a short summary? Also explain the conflict. Some Traits of an epic hero also. Please help!!!
*October 24, 2010*