# Posts by robyn

Total # Posts: 62

**math**

the amount of radioactive substance prsent at anytime is given by q(t)=Q0e-0.1 How will it take for the radioactive substance x to decay to 30% of its original amount?

*January 10, 2016*

**Healthcare finance**

Lansing Surgical Supplies Inc, sells on terms of 2/10, net 30. Gross sales for the year are 1.3 million and the collections department estimates that 30 percent of the customers pay on the tenth day and take discounts, 40 percent pay on the thirtieth day, and the remaining 30 ...

*December 13, 2015*

**Chemistry**

Showing all calculations and specific references to the equipment needed, describe how to prepare 500mL 0.250mol/L potassium iodide(KI) solution.

*June 17, 2015*

**Chemistry**

A solution containing excess lead(ii) nitrate is reacted with 380.0ML of 0.250mol/L potassium iodide solution. A bright yellow Precipitate is of lead(ii) iodide is formed. Calculate the mass of lead (ii) iodide that should be formed. Pb(NO3)2+2KI-> 2KNO3+PbI2

*June 17, 2015*

**math**

There are 120 tickets being sold for a raffle contest. There is one winning ticket. Lana buys 10 tickets. What are the probability she will win the prize

*May 26, 2015*

**Math**

Assume a three-month CD purchased for $3000 pays simple interest at an annual rate of 10%. What is the balance at maturity? I don't have any work. This is question one and I have 19 more. I don't understand how to arrive at the answer.

*October 26, 2014*

**Science**

Answers were all correct 100%

*March 4, 2014*

**math**

write a five digit number that fits each description use only the digits that the athlete are wearing use each digit only once in each answer find the greatest number less than 1.8 1. The digits ate 41836

*December 12, 2013*

**math**

write a five digit number that fits each description use only the digits that the athlete are wearing use each digit only once in each answer find the greatest number less than 1.8 1. The digits ate 41836

*December 11, 2013*

**math**

3.1648

*December 11, 2013*

**chemistry**

Acetic acid (CH3COOH) has a Ka of 1.8x10^-5. a buffer is to be prepared with a pH of 5.00 from solutions of CH3COOH and sodium acetate (NaCH3COO) of the same concentration. How many mLs of NaCH3COO would have been added to 100 mL of CH3COOH to make the proper buffer solution??

*November 19, 2013*

**chemistry**

titration question: How many moles of HCl must have been present in the 25mL of HCl solution in the 2 trials? Given: Trial 1: V of HCl= 25.00mL, V of NaOH used=29.50mL and M of NaOH=0.18M Trial 2: V of HCl=25.00mL, V of NaOH used=28.50mL and M of NaOH=0.18M

*October 28, 2013*

**Math**

In the equation (8a^5)/b, how would you bring the b to the numerator and get rid of it in the denominator?

*August 17, 2013*

**Math**

If I multiply again I get 52. Is that correct? Thanks

*June 9, 2013*

**Math**

How many square inches of wrapping paper are needed to entirely cover a box that is 2 inches by 3 inches by 4 inches? I did lxwlh and got 26 Is this correct

*June 9, 2013*

**Math**

What is the product of (3x+2) and (x-7)? I got 3xsquared-23x-14. Is this correct?

*June 9, 2013*

**Math**

Thank you, so my answer would be 1.7

*June 9, 2013*

**Math**

Peter walked 8,900 feet from home to school. How far to the nearest tenth of a mile did he walk? 1mile=5,280feet I got 1.6. Is this correct?

*June 9, 2013*

**poetry**

In" fire and ice" Frost compares fire to

*February 4, 2013*

**statistics**

You intend to estimate a population proportion with a confidence interval. The data suggests that the normal distribution is a reasonable approximation for the binomial distribution in this case. Find the critical value that corresponds to a confidence level of 98%. (Report ...

*July 22, 2012*

**statistics**

Assume that a sample is used to estimate a population proportion p. Find the margin of error M.E. that corresponds to a sample of size 344 with 96 successes at a confidence level of 98%.

*July 22, 2012*

**chem**

How many grams of ibuprofen contain 7.1x10^25 atoms of C? Ibuprofen is C13H18O2. Molar Mass is 206. The answer is=1870 grams. How do I calculate this to get this answer? Please help!

*May 7, 2012*

**CHEMISTRY**

For the following reaction at equilibrium, indicate if the equilibrium mixture contains mostly products, mostly reactants, or both products and reactants. 2H20(g)-><-2H2(g)+O2(g) kc+4x10-48

*May 6, 2012*

**math**

a pattern uses 3 1/6 yards of fabric to make a skirt. what is the largest number of skirts that can be made from 20 yards?

*April 26, 2012*

**Statistcs**

Assume that a ramdom sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confinence level. n=550, x=165, 95% confindence

*March 27, 2012*

**Statistics**

On a chemistry exam, Student A scored a 81 and Student B scored a 70. The mean for the class was 75 and the standard deviation was 3.8. What percentage of students scored in somewhere in between Student A and Student B?

*February 12, 2012*

**Chemistry**

Calculating the enery in joules required to heat a 256 grames of water at -107 degrees to 333 degrees

*January 17, 2012*

**calculus**

5) Find the points on the curve below at which the tangent is horizontal. Use n as an arbitrary integer. (Select all that apply.) y=Sin(x) / 2+ Cos (x)

*October 28, 2011*

**math**

he had 16 pears in the basket. because 8x2=16.

*October 13, 2011*

**Statistics**

How would you interpret the findings of a correlation study that reported a linear correlation coefficient of − 1.34?

*October 11, 2011*

**Statistics**

Starting with the data values 70 and 100, add three data values to the sample so that the mean is 81, the median is 94, and the mode is 94. Please show all of your work.

*October 6, 2011*

**chemistry 12**

For the acid-base neutralization reaction of Carbonic acid, H2CO3(aq) and lithium hydroxide, LiOH(aq), write the blanced: a)complete equation b) Ionic equation c) Net ionic equation. ----------------------- i got a) H2CO3(aq) + 2LiOH(aq) = 2H2O(l) +Li2CO3(aq) i know my answers...

*October 4, 2011*

**chemistry 12**

Identify the two conjugate acid-base pairs in each of the following: A) H2PO4^-(aq) + HSO4^-(aq) = H3PO4(aq) + SO4^2-(aq) B) HI(aq) + CN^-(aq) = HCN(aq) + I^-(aq) i got a) H2PO4^- , HSO4^- and SO4^2- b) CN^- and I^- But i don't think that these are right, please help!

*October 4, 2011*

**Statistics**

A random sample of size 36 is to be selected from a population that has a mean μ = 50 and a standard deviation σ of 10. - - Find the mean of this sampling distribution. - Find the standard error of this sampling distribution.

*September 30, 2011*

**chemistry 12**

i got all the answers now Doctor Bob. thank you so much for your help! its muchly appreciated!

*September 26, 2011*

**chemistry 12**

okay i have the vaule of K being 6.527. I'm just confused as to how to start the teials. do i just do (b)/(a)(c), (a)/(b)(c) and (c)/(a)(b) ?

*September 26, 2011*

**chemistry 12**

Equilibrium concentrations (a)(mol/L)// (b)(mol/L)// (c)(mol/L) 0.040 // 0.066 // 1.72x10^-2 0.080 // 0.017 // 8.8x10^-3 0.030 // 0.024 // 4.7x10^-3 My data was collected at 25○C for the reaction A(g) + B(g) = C(g) What i have to do now is involving three different ...

*September 26, 2011*

**Physics**

Heyy is anybdy good at physics I am stuck on this question ... ... A camper van with a mass of 2500 kg has a maximum driving force of 2650 N. The camper van drives along a straight road at a constant speed of 90 kilomatres per hour. At this speed, air resistance is 2000 N and ...

*September 9, 2011*

**Physics**

6.3 (ish)seconds !

*September 8, 2011*

**Mathematics**

What are the differences and similarities between a regular pentagon and an irregular pentagon

*August 15, 2011*

**math**

A ship left at 9:00 am going 10 miles per hour on a course. Another ship left at noon on the same course going 15 miles per hour. At what time did the second ship overtake the first ship?

*May 19, 2011*

**algebra**

name 4 positive numbers less than 2

*May 4, 2011*

**College Chemistry**

Determine how many grams of water can be produced from excess propane C3H8 and 2.55g oxygen? MM 02 = 32 and MM H2O = 18.2. I tried 2.5 gm O2 X 5 mole O2/32.00 gm O2 x 4 mole H2O/5 mole O2 = 1.40. This is close but not correct. The answer is 1.15. Can you help with this?

*April 24, 2011*

**pharmacy tech**

A certain mixture calls for 6mg of amoxycillin to 15 liters of water How many liters of water would you need for 12mg of amoxycillin?

*December 29, 2010*

**chemistry**

9.55%

*June 21, 2010*

**Algebra**

Solve the system of equations by the substitution method {y=1.2+3.8 {Y-0.5x-2.99

*June 3, 2010*

**Physics**

A telescope with a small circular aperture of diameter 2.0 centimeters. If two point sources of light are being imaged by this telescope, what is the maximum wavelength at which the two can be resolved if their angular separation is radians?

*April 22, 2010*

**Physics**

The microscope has a converging lens (the eyepiece) with a focal length of 2.50 mounted on one end of a tube of adjustable length. At the other end is another converging lens (the objective) that has a focal length of 1.00 . When you place the sample to be examined at a ...

*April 22, 2010*

**physics**

the 4m line should intersect with the arrow on the right of the 3m line.

*October 8, 2009*

**physics**

For the following vector addition diagrams, use Pythagorean Theorem to determine the magnitude of the resultant. Use SOH CAH TOA to determine the direction. Use the tail end relative to due east. ^ I 4 m I ------>I 3 m I've got the Pythagoren Theorem and the angle ...

*October 8, 2009*

**MATHS**

2 1/4 ÷ 5 = 9/20 9/20 x 8 = 18/5 18/5 = 3.6 3.6 cups

*September 13, 2009*

**stastics**

Imagine that you have 10 CDs and 10 envelopes on a table before you; each CD and each envelope are labelled with a number such as 7 or 10. If you randomly put the CDs into the envelopes provided, what is the probability of matching only one CD into the wrong envelope?

*July 25, 2009*

**Math**

if 7y=2x-5 what does x=

*June 12, 2009*

**SKILLS FOR THE EFFECTIVE TEACHER AIDE**

madenah some of the test answers and questin different order because lins answers are correct check you question and answers to the ones at the top of this page all of lins answers are in order with this form of the test because mine were too and i made a 100 thanks

*January 9, 2009*

**adult education**

Define and discuss the similarities and differences between routine and positive messages, negative messages, and persuasive messages

*December 19, 2008*

**social studies**

which president set three unique records while in office?

*November 27, 2008*

**health**

Make the family feel very powerles when it comes to helping their loved one. Not only put the addicts health and safety in jepordy but also evryone that encounters them. Alcoholics often put their loved ones in the position to deal with the law as well as people that mistreat ...

*November 26, 2008*

**AP Chem**

Consider the following unbalanced equation: Ca3(Po4)2+H2SO-->CaSO4+H3PO What masses of calcium sulfate and phosphoric acid can be produced from the reaction of 1.0 kg calcium phosphate with 1.0 kg concentrated sulfuric acid (98% H2SO4 by mass)? I'm so lost. Please help.

*November 4, 2008*

**Language arts**

I am trying to assist my fourth grader in writing her first book report. It is based off of a mystery book. I have looked everywhere for a basic guildline for her so that I can give her an idea of what to do without doing it for her.Can anyone please guide me so that I can ...

*October 20, 2008*

**health**

what are five appearance and grooming factors that result in a professional image.

*October 19, 2008*

**St. John's College**

In what year was Beryl Higgs ordained?

*October 2, 2007*

**novel= death on the ice english**

i think that when you ask for chapter summaries his site shouls give you chapter summaries, not " nO ONE HAS REPSONDED TO THIS MESSAGE " I MEAN WHAT KINDA BUSINESS ARE YOU RUNNING HERE :o

*September 22, 2006*

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