Posts by heidi

Total # Posts: 153

Biology
What molecules carry the energy derived from breaking down glucose? Where are these molecules made? Now, I'm thinking ATP and NADH but I'm not sure. Both these molecules are made outside the mitochondria in the cytoplasm.

Chemistry
Thank you! I would've been able to handle this problem without any help if I had realized it 2=n instead of 2L.

Chemistry
I was thinking this entire time 2L meant two liters. My professor just didn't put a space between the 2 and the L. L has nothing to do with the two, it has to do with the compound itself.

Chemistry
d=difference. Wow, okay- makes more sense now.

Chemistry
d as in derivative? How would I factor in the 2L though? That's also throwing me off.

Chemistry
Temperature is at 25C, I forgot to add that!

Chemistry
Find the equilibrium constant for the following reaction: D-Glucose (aq) <-> 2L (+) lactic acid (aq) ?G ° for D-Glucose= -914.5kJ/mol ?G ° for lactic acid = -538.8kJ/mol Would I just use the ?G° =-RTlnK?

algebra
solve the following system of equations, please show work 3x-2y+z=12 x+3y+z=-4 2x+2y-4z=6

Chemistry
Take into account correction factors for phosphate buffers, predict the pH when 0.50ml of 1M HCl is added to 40mL of .10M buffer at expected pH 6 and pH 6.5. The buffer was made with Na2HPO4 and NaH2PO4. pKa is 7.2. When I did this before, I got a lower pH for 6.5 than I did ...

Chemistry
And, the whole pH 6 thing still doesn't make sense. I just took the absolute value and got a change in pH of .0095.

Chemistry
@DrBob222 oh, so instead of solving for change in pH we stop after a+b=4mmols. so it'll be different when it goes to .01M. But 7.5=7.2+logb/a; b=2a a+b=.004mols; 3a=.004 a=.00376 b=.000237. So that would be my final answer for pH 7.5 and I do the same for pH 6?

Chemistry
How many moles of conjugate base (Na2HPO4) are present in 40mL of .010M buffer at pH 7.5 vs at pH 6? Buffer was made up of Na2HPO4 and NaH2PO4. pH=pKa +log[A/HA]; pKa=7.2.... When I did the calculations I got the same amount as if it were in a 0.1M buffer at the same pH's ...

Chemistry
Ignore the second post at 10:32, I'm going to post it as it's own question!

Chemistry
How many moles of conjugate base (Na2HPO4) are present in 40mL of .010M buffer at pH 7.5 vs at pH 6? Buffer was made up of Na2HPO4 and NaH2PO4. pH=pKa +log[A/HA]; pKa=7.2.... When I did the calculations I got the same amount as if it were in a 0.1M buffer at the same pH's ...

Chemistry
@DrBob222 Ahh. So I can't use this calculation to calculate the pH with the addition of a phosphate buffer correction factor? Because I'm asked to calculate the pH using phosphate correction factor when 0.50ml of 1M HCl is added to 40mL of .10M buffer at expected pH 6 ...

Chemistry
@DrBob222, would I follow this same format if I wanted to find predicted pH with the pH correction factors. for example, I would expect a solution I made with ideal pH 7.5 to have a pH of pH=7.2+log(2.2/1.8)+log(.45/.74)=7.07. Correction factors were given to us. But now ...

Chemistry
So .24/40=.006 7.2+log[.006/4.26]=4.35 so that's a huge change in pH (1.47). Which makes sense because there's excess HCl. expected pH of a substance. So

Chemistry
Not to mention I also have to do this for 40mL of a .01M and all those will be negative following the same steps. I understand that 1M(mole/L) is the same as 1mmol/mL but I don't see how that helps as well. @DrBob222

Chemistry
@Dr.Bob222 I guess I'm still not following what you're saying. Following the above method I got a=3.76 and b=.237. If I were to subtract the .5 I would get -.263 for HPO4 and 4.26 for H2PO4 (added obviously). I understand a negative number is showing excess HCl but I ...

Chemistry
Do you just take the absolute value for pH 6? @DrBob222

Chemistry
Use the henderson-hasselbalch equation to predict the change in pH when 0.50ml of 1M HCl is added to 40mL of .10M buffer at pH 6 and pH 7.5. My two solutions are Na2HPO4 and NaH2PO4.pKa=7.2 Now I don't even know where to begin and how to use the equation.

math
if tammy can clean 1/2 the area in an hour by herself and melissa can clean 1/3 the area by herself in an hour then how long will it take them to clean the area together.

math models
Martin invested $6,500 in a bank at a simple interest rate of 6.5%. How much interest would he receive after 4 years? Use I=PRT

Math
1.64 as a mixed number in simplest form

Math
What is 5/6 of 1/2

Algebra
Simplify by reducing (4y^2z^3-8yz^2)/(yz^2-2z)

geometry
a parabola whose axis is parallel to the y axis passess through the points {1,1), (2.2) and (-1,5). Find the equation of the parabola

Physics, Statistics
Consider a series of 8 flips of a fair coin. (a) Calculate the probabilities for obtaining 0-8 heads. We will consider each of these nine outcomes to be macrostates of the system. (b) Calculate the entropy for each of these macrostates. I was able to figure out part A, but I&#...

Algebra I
It is the formula my teacher gave me so I suppose that's what I'm supposed to do. Thank you.

Algebra I
Tommy owes 3000 on his credit card. He is paying 14.5% interest compounded monthly. If it takes him 4 years to pay off the balance, what was the total amount that he ended up paying. Okay, so it gives me the equation a=p(1+r/n)^nt I did 3000(1+.145/12)^48 and got $5339.52 Is ...

Chemistry
How many atoms are in 448 grams of carbon?

Physics
suppose you want to design a capacitor that uses mica as the dielectric material which has K = 7 and a dielectric strength of 150 MV/m. It is intended to store at least 1.- J of energy and be able to withstand a voltage up to 250 volts without electric breakdown. a) What is ...

Physics
suppose you want to design a capacitor that uses mica as the dielectric material which has K = 7 and a dielectric strength of 150 MV/m. It is intended to store at least 1.- J of energy and be able to withstand a voltage up to 250 volts without electric breakdown. a) What is ...

Physics
Consider the following model for the electrostatic stretching of DNA. A spring with spring constant kDNA = 250 pN/m is tethered to an immobile surface on one end and a charge of qDNA = −350e on the other. A uniform electric field of magnitude |E| = 2.5 N/C is ...

In need of algebra help!
You are making a rectangular table. The area of the table should be 10 ft^2. You want the length of the table to be 1 ft shorter than twice its width. What should the dimensions of the table be? Okay, so, I'm not sure how to put this into an equation. The example in the ...

Math
Andrew has a combination of 8 quarters, dimes and nickels that add up to a value of 95 cents. How many of each coin does Andrew have?

Math
a basketball tournament starts with 64 teams. after one loss the team is out. how many games does the team that wins the tournament have to play? 64/2=32 32/2=16 16/2=8 8/2=4 4/2=2 2/2=1 The answer is 6 games. How would I write the number sentence?

math
The ratio of one side of a polygon to the corresponding side of a similar polygon is 5:8 The perimeter of the second polygon is 96. What is the perimeter of the first polygon.

math
what is the base 10 of 469 3rd grade

Statistics/Probability
The life span of a calculator has a normal distribution with a mean of 60 months and a standard deviation of 5 months. If a calculator is randomly selected, find the probability that the calculator has a life span of. (1) more than 50 months (2) between 4 years and 6 years.

Statistics/Probability
The probability the New Year's day is on Saturday is a randomly chosen year is 1/7. 15 years was chosen randomly. Find the probability that, (1) Exactly four of these years have a New Year's day on a Saturday. (2) At least two of these years have New Year's day on ...

Statistics
The life of an electric light bulb is known to be normally distributed with a mean of 2000 hours and a std. of 120 hours. Find the probability that the life of such a bulb would be. (a) greater than 2150 hours (b) within the range of 1850 hours to 2090 hours

statisticss
The time taken by a man to deliver milk is normally distributed with, mean 12 minutes and standard deviation 2 minutes. He delivers milk everyday estimate the probability that he takes. (a) longer than 17 minutes (b) between 9 and 13 minutes

Math (statistics)
In an examination a candidate is given the four answers to four questions but is not told which answer applies to which question. He is asked to write down each of the four answers next to its appropriate question. b). show that there are 6 ways of getting just two answers in ...

Statistics
An unbiased die is thrown seven times. Find the probability of throwing it at least five six's.

math
In an examination a candidate is given the four answers to four questions but is not told which answer applies to which question. He is asked to write down each of the four answers next to its appropriate question. b). show that there are 6 ways of getting just two answers in ...

Chemistry
A butane lighter had a mass of 24.643 grams before lighting and a mass of 24.592 grams after. How many mL of CO2 were produced? Assume STP.

Chemistry
5.2 grams of magnesium metal are place in 400.0 mL of 1.0 M hydrochloric acid. The balanced equation for the reaction is: Mg + 2HCl = MgCl2 + H2. How many moles of H2 gas were produced?

math
what means out of 100?

math
brick= (3/4)+(3/4) brick=(6/4)=1.5

calculus
27 ft of wire is to be used to form an isosceles right triangle and a circle. Determine how much of the wire should be used for the circle if the total area enclosed is to be a minimum? Maximum?

algebra
you invest $2800 in an account that pays an interest of 5.5%, compounded continuously. calculate the balance of your account after 12 years.

math
Decrease

math
40% to 525 what is original amount.

science
A satellite completes one revolution of a planet in almost exactly one hour. At the end of one hour, the satellite has traveled 2.0 × 107 meters and is only 10 meters away from its starting point. What is the numerical value of the satellite's average velocity after ...

Physics
Thank you so much... Huge help

Physics
Calculate the ratio of the drag force on a jet flying at 1049 km/h at an altitude of 10.0 km to the drag force on a prop-driven transport flying at 560 km/h and at an altitude of 5.00 km. The density of air is 0.380 kg/m3 at 10.0 km and 0.670 kg/m3 at 5.00 km. Assume that the ...

Physics
A block with mass m = 16.1 kg slides down an inclined plane of slope angle 24.3o with a constant velocity. It is then projected up the same plane with an initial speed 3.35 m/s. How far up the incline will the block move before coming to rest?

Physics
Two blocks with masses m1 = 1.40 kg and m2 = 3.00 kg are connected by a massless string, as shown in the Figure. They are released from rest. The coefficent of kinetic friction between the upper block and the surface is 0.390.In the figure m1 is on top of a horizontal table ...

math
45 is the sum of 13 and Rita's score.

Statistics
A unbiased die is thrown seven times. Find the probability of throwing at least five six's.

health
When a person has episodes of hypomania that shift back and forth with mild depression for at least two years, he or she has what form of bipolar disorder? A. BP-NOS B. Cyclothymic Disorder C. Bipolar I Disorder D. Bipolar II Disorde A?

health
In 2004, which ethnic or racial group was at a lower risk of suicide for people ages 65 or older? A. Hispanics B. Asian and Pacific Islanders C. Non-Hispanic Blacks D. Non-Hispanic Whites c

Physics
A downward force of 5.1 N is exerted on a -7.3 mcirco C charge. What is the magnitude of the electric field at this point?

math
Mine was wrong this is my husbands work. I am having a hard time understanding this math. (daughters 5th grade).Does place value start to the right of the decimal with tens?

math
I'll try.... 17; 17.001; 17.107; 17.11

math
can you put the following nmbers in order form least to greatest? 17.11; 17.107; 17; 17.001

business math
sam buys a $10,000.00 teasury bill at 5 1/2% what is the effective ratr?

math
if two angles are supplementery and one is 48 degrees more than 3 times the other what is the measure of the smaller angle

organic chemistry
how to calculate the % oil of thyme in thyme ? We did an experiment titled : the extraction of Thymol in thyme oil and the prof wants us to calculate the % oil of thyme in thyme... how do I do that ? Thanks

organic chemistry
how to calculate the % oil of thyme in thyme ? We did an experiment titled : the extraction of Thymol in thyme oil and the prof wants us to calculate the % oil of thyme in thyme... how do I do that ? Thanks

organic chemistry
how to calculate the % oil of thyme in thyme ? We did an experiment titled : the extraction of Thymol in thyme oil and the prof wants us to calculate the % oil of thyme in thyme... how do I do that ? Thanks

Organic chemistry
If the aspirin crystals were not completely dried before the melting point was determined, what effect would this have on the observed melting point ?

algebra
How do I divide 3sqrt40 by 3sqrt5?

psy
17. <11{6[1(07)71]}> The higher the price of an antique, the greater people’s expectation that the object is rare. That, in turn, makes the antique appear more valuable. If the statements above are correct, then offering an antique for sale at a bargain price (...

psy
<11{6[1(07)71]}> The higher the price of an antique, the greater people’s expectation that the object is rare. That, in turn, makes the antique appear more valuable. If the statements above are correct, then offering an antique for sale at a bargain price

Math
The length of a rectangle is 10cm greater than the width. The area is 551cm^2. Find the length and width

Math
x^2+bx+45, Find the value for b such that the trinomial is a square

math
Mr.Shea saved $2,500 in April. His monthly salary is Twice the amount he saved in April. In May, he saved a certain amount of money.He spent $4,200 more than the amount he saved. How much did he save in May.

math
you have a 20 x 20 area and you have 4 14 foot fences plus 4 4 foot fences and you need to house 9 dogs and none can be together how do you do it?

Chemistry
Beginning with the ideal gas equation show how density of a vapor may be determined? I have so far: n = (PV)/(RT) d= m/V n= m/MW by rearranging i get d = P(m/MW)/RT

English
MLA has updated. Now you have to include what sort of medium was used. in this case you should end with Print if a print source or Web if a web source. The other piece might be in the teacher asked you to include the url.

algebra
im just looking for problem set up

algebra
the number of students is 150 more than adults, the student tickets are $3 and adult tickets are $5 the total sales was 4730 how many students attended

Chemistry
How many grams of hydrogen can be produced by the electrolysis of water with a current of 0.290 A running for 5.00 min?

english/phonlogy
I need help in a project. I'm teaching a group of german students and I have noticed they say things like 'dis' and 'lai' instead of 'this' and 'lie'. I should identify the phonology problem and explain it precisely what it is. Please, can ...

arithmetic
WHAT IS THE ARITHMETIC MEAN OF 3, 5, 7, 9 AND 11

discrete math
Fill in the blanks: For all sets A and B, if A is in the set of B, then A union B in in the set of B. Proof: Suppose A and B are any sets and A in in the set of B. [we must show that __________] Let x be and element of _______. [we must show that __________] by definition of ...

Chemistry
225g

microbiology
Which are the two other pathways necessary to obtain enough energy to accomplish the task?

Chemistry
To what volume should you dilute 50.0 mL of a 4.50 M KI solution so that 28.5 mL of the diluted solution contains 2.75 g of KI?

english
Thank you very much!!! The verb tenses are both present perfect?

english
or this... When a student has chosen to continue his or her education, her or she has started towards being financially secure in life.

english
When a student has chosen to continue their education, they have started towards being financially secure in life. Is that better?

english
When a student has chosen to continue their education, they have also started towards being financially secure in life. has chosen is part tense participle Is "have also started" present perfect tense?

Physics
Beatrice throws the 1st calculator straight up from the edge of the roof of a building. She drops a 2nd calculator off the side of the building 2 seconds after she has thrown the first one. If the height of the building is 40m, what must the initial upwards velocity of the 1st...

PHysics
.) Bailey has taken up parkour. She attempts to clear the gap between two buildings. Bailey is on a roof which is 50m high and she is attempting the jump to a building that is 42m high. a.) If the two buildings were built touching (i.e. there is no gap) How long would it take ...

Physics
.) Beth launches a rocket out in the courtyard. It stays in the air for 7.25 seconds before coming back down. a.) How high did it get? b.) With what velocity did it hit the ground upon returning to Earth? c.) What is its rate of acceleration as it slows down, reaches the peak ...

world history
how do i do a report that is due in 2 day that is on the 5 themes of geography and has to do with a current event i need help and i am having a break down how can i work like this HHHHHEEEEEELLLLLLLPPPPPPP ME

Algebra
A single-engine airplane carries enough fuel for an 8-hour flight. After the airplane has been flying for 1 h, the fuel tank begins to leak at a rate that would empty the tank in 12 h. How long after the leak begins does the plane have until it runs out of fuel?

  1. Pages:
  2. 1
  3. 2
  4. Next>>