Monday
December 22, 2014

Posts by Lisa


Total # Posts: 3,062

chemistry
HELP
October 19, 2010

probability
icrobes in a certain colony exposed to radiation have a 1/6 chance of being mutated. a. If ten microbes from the colony are sampled, what is the probability that at most 4 will be mutated? b. If microbe from the colony is examined one by one, what is the probability that the ...
October 19, 2010

Physics
Assume cathy has to drag her suitcase along the floor of the airport terminal by a rope. The rope makes a 40.0 degree angle with the horizantal. The suitcase has a mass of 36.0 kg and Cathy pulls on the rope with a force of 65.0 N. a) What is the magnitude of the normal force...
October 18, 2010

probability
Microbes in a certain colony exposed to radiation have a 1/6 chance of being mutated. a. If ten microbes from the colony are sampled, what is the probability that at most 4 will be mutated? b. If microbe from the colony is examined one by one, what is the probability that the ...
October 18, 2010

Physics
Assume cathy has to drag her suitcase along the floor of the airport terminal by a rope. The rope makes a 40.0 degree angle with the horizantal. The suitcase has a mass of 36.0 kg and Cathy pulls on the rope with a force of 65.0 N. a) What is the magnitude of the normal force ...
October 18, 2010

Chemistry
You receive two samples of a substance. After testing, it shows that one sample contains 88% oxygen by mass an 12% hydrogen. The second sample contains 94% oxygen and 6% hydrogen. Is it possible that the two samples are the same? Explain. thanks, I appreciate the help !
October 17, 2010

Chemistry
You receive two samples of a substance. After testing, it shows that one sample contains 88% oxygen by mass an 12% hydrogen. The second sample contains 94% oxygen and 6% hydrogen. Is it possible that the two samples are the same? Explain. thanks, I appreciate the help !
October 17, 2010

Organic Chemistry - Melting Point
You have an unknown with an observed melting point of 90-93°C. Is your unknown compound A with a reported melting point of 95.5-96°C or compound B with a reported melting point of 90.5-91°C? Explain.
October 17, 2010

Chemistry
NiF2(aq)+Fe2(SO4)3(aq) ==NiSO4 (aq) + FeF3 (s) balance each of the following chemical equations. Express your answer as a chemical equation. Identify all of the phases in your answer. Can help me refresh my memory ...
October 16, 2010

probability
A company's records indicate that on any given day, 1% of their day shift employees and 2% of the night shift employees will miss work. Sixty percent of the employees work the day shift. a. What percent of employees are absent on any given day? b. A randomly selected ...
October 16, 2010

probabilityv
A school's administrators are concerned about absenteeism at their school and the e ect it has on students' grades. The following data were compiled, based on a sample of students. Student's Absent Medium Absent Grade Infrequently Absent Frequently Low 1 9 8 ...
October 16, 2010

Chemistry
thank you
October 15, 2010

Chemistry
Nitric acid is a component of acid rain that forms when gaseous nitrogen dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous nitric acid. Write a balanced chemical equation for this reaction. Express your answer as a chemical equation. Identify all of...
October 15, 2010

Chemistry
and I finaly got #1 it is Al2O3
October 15, 2010

Chemistry
I finaly got #2 it is K2O
October 15, 2010

Chemistry
Write a formula for the ionic compound that forms between each of the following pairs of elements. 1. aluminum and oxygen Express your answer as a chemical formula. AlO and Al2O3 and Al2O3 the 2 was the bottom right cornor and I got this message Use subscripts to represent the...
October 15, 2010

Chemistry
thank you so much you are awesome. ;-)
October 15, 2010

Chemistry
whoops Write a formula for the ionic compound that forms between each of the following pairs of elements
October 15, 2010

Chemistry
zink and sulfur Express your answer as a chemical formula. I entered Zn+2,S-2 and it said this to me There is an error in your submission. Make sure you have formatted it properly.
October 15, 2010

Chemistry
THANKS
October 14, 2010

Chemistry
i put 44.3x131.30=5.81659E3 thats the answer it got, so I put it in 3 significant figures. I guess I am really confuss
October 14, 2010

Chemistry
5.81 g is that right
October 14, 2010

Chemistry
What is the mass, in grams, of each of the following? 44.3 mol Xe
October 14, 2010

Chemistry
m= 4.90 g
October 14, 2010

Chemistry
3.57×10−2 mol Ba Express your answer using three significant figures
October 14, 2010

3rd grade math
8 times 493= 3944 using distributive property then solve with array showing the work
October 14, 2010

5th grade/ Math
Your Max (highest number) = 18 Your range is 13 so your minimum number in your set =5 You need the mean to = 12 so all twelve numbers in your set have to equal 144 so that the 12 individual numbers will have a mean of 12 (144/12=12). The mode = 7 - so 7 is going to occur more ...
October 14, 2010

Math
I have a few questions about T-Matrix. In excel, I am suppose to work with powered matrices to construct a weighted T matrix, using a scalar of .7. Does this mean I multiply each of the powered matrices by .7? Or do I power the powered matrices by .7? Or am I completely off ...
October 13, 2010

english - thesis statement
Based on the reading Wolf-Alice by Angela Carter I need to put together a thesis statement, regarding the development of self identity. Wolf-Alice is a feral child who lived with a pack of wolves. Group of nuns take her in to try to show her human ways (since she couldnt be ...
October 13, 2010

statistics
Considering that a researcher can test at the <p = .05 (95%), p = .01 (99%), or p = .001 (99.9%) level for statistical significance, how do you use these three levels in relationship to evaluate risk to patients in implementing the decisions based on research findings?
October 12, 2010

Algebra
please show steps solve 9 - (9)squared > 10x - x
October 11, 2010

Algebra
-4 - 2n + 4n > 7 - 4
October 11, 2010

Algebra
Homework help please: algebra inequality 0.3 - 0.5n + 1 is greater than or equal to 0.4
October 11, 2010

Physics
A horse canters away from its trainer in a straight line, moving 120 m away in 11.0 s. It then turns abruptly and gallops halfway back in 4.9 s.
October 11, 2010

English
What would be good sentence for emerald?
October 11, 2010

English
I needed to create sentence containing the phrase "green with envy". I have got two sentences here, but I need help picking out the one that makes more sense. Emily’s new look made her friends green with envy. Emily’s friends became green with envy when ...
October 11, 2010

Science
Thank you Sra! This is for 7th grade science - so it looks as though dynamic condition is a state of constant moving until all parts are equal and static condition is motionless. Do you know if this correct?
October 11, 2010

Science
The state of cellular equilibrium is best described as a dynamic condition, not static. What does this mean?
October 11, 2010

American Democray
The president's role in foreign policy increased largely because: a Congress proved so inept in foreign affairs that the american people demanded a change b America became more of a world poer c of the need to coordinate national economic poicy and foreign policy, a task ...
October 10, 2010

Chemistry
What is the specific heat (in cal) of fat with a degree change from 25 degrees Celsius to 35 degrees celsius? Density of fat = 0.94 g/cm^3
October 7, 2010

Math
Betsy, a recent retiree, requires $6,000 per year in extra income. She has $60,000 to invest and can invest in B-rated bonds paying 13% per year or in a certificate of deposit (CD) paying 3% per year. How much money should be invested in each to realize exactly $6,000 in ...
October 6, 2010

chem
Po-218 is an alpha emitter with a half-life of 3.0 minutes. If a sample contains 69 mg of Po-218, how many alpha emissions would occur in 6.0 minutes? the answer has to be _________a emmisions (which I have no idea what it means) and I use a chart thing with amount, #H-L, and ...
October 5, 2010

Chemistry
Draw the lowest energy conformation of 3-ethyl-2,4,4-trimethylheptane, depicting the C3-C4 bond on a sawhorse. How would i do this? i am so lost
October 5, 2010

geometry
fine the perimeter of ABCD = 46. AB = x+9, CD= 2x-7
October 4, 2010

math
what does equivalent mean?
October 4, 2010

8th grade math
I understand that part but I'm just not sure when the question asks me what VALUE will make the equation TRUE will it be x=-72? because I don't think that's what there asking me.
October 4, 2010

English composition
Music during slavery: A call to arms or a panacea?
October 3, 2010

chem
Write a partial decay series for Rn-220 undergoing the following sequential decays: á (alpha decay), á, â(beta decay), á. (Enter the mass number in the first raised box, the atomic number in the second lower box and the symbol of the element in the ...
September 30, 2010

Math
Im pretty sure you could use the pythagorean theorem a^2 + b^2 = c^2 just plug in the numbers you have and solve for c
September 30, 2010

spanish
Im not quite sure what your asking do you mean something like tus companeros de clase?
September 30, 2010

math
median=90 you find the median by putting all the numbers in order and finding the middle number
September 30, 2010

math
47 rounded to the ten's place is 50
September 30, 2010

chemistry
oops b and c should be b decay and in the directions its a,b,a,b
September 30, 2010

chemistry
Write a partial decay series for Po-214 undergoing the following sequential decays: á, â, á, â. Use e for an electron. Use the format +1 or -1 for charge. a)a decay b)â decay c)a decay d)â decay
September 30, 2010

chem
(b) If the natural abundance of Ag-107 is 51.84%, what is the natural abundance of Ag-109? 48.16 % (c) If the mass of Ag-107 is 106.905, what is the mass of Ag-109? 108.9 amu so i got the answers correct but kinda forgot how because it took me a while so do you think you could...
September 29, 2010

11th grade
sound travels at 350 m/s in warm air. "If you hear the echo in 10 seconds, how far away is the reflecting surface?
September 28, 2010

science, density
The density of sea water is slightly higher than that of fresh water. The higher density is due to the fact that sea water contains salts such as sodium chloride and magnesium chloride. Suppose you have a container that holds 5.00 kg of fresh water, which has a density of 1.00...
September 28, 2010

Math
how do I solve this problem. In 1920 the record for a certain race was 445.7 sec. In 1970, it was 44.2 sec. Let R(t) = the record in the race and t = the number of years since 1920. a) Find a linear function that fits the data R(t) = b) What is the predicted record for 2003? c...
September 26, 2010

The Young Child and the Environment
When a child not only throws a ball farther than she had previously, but also changes the way the throws the ball, the change is called A. Cumulative B. Multifactoral C. Quantitative D. Qualitative
September 23, 2010

Chemistry
A sample of gas occupies 3.00 L at 760 torr. Calculate the volume it will occupy at 1.45 atm and the same temperature?
September 23, 2010

Chemistry
A balloon filled with helium has a volume of 1.oo x 10^3 L at 20 degrees c. What will be the balloons volume at 30 degrees c, if the pressure surrounding the balloon remains constant?
September 23, 2010

sport
If air resistance is negligible what would the flight path of a shot from the moment of release to the moment immediately prior to landing look like using newtons 3rd law of motion?
September 22, 2010

sport
Can you name and explain 3 factors (excluding air effects ) which should be utilised by a shot putter to optimise the distance thrown using newtons trird law of motion
September 22, 2010

Sport
Why is the flight path of a shot putt different to that of a badminton shuttle using newtons third law of motion?
September 22, 2010

sport
How do i explain the effect of air resistance on the flight of two badminton shuttles, the first of which has been struck hard (with a greater application of force) and the second which has ben struck gently?
September 22, 2010

Sport
How do I explain using Newtons 3rd Law the nature of the reaction force which provides impulsion for a cyclist?
September 22, 2010

Physics
Bobpursley -- I do not understand. The answer was 5.7 s and I have no idea what equation was used to get that.
September 21, 2010

Physics
Can someone help me to understand how to work out this problem? The pilot of an airplane traveling 240 km/h wants to drop supplies to flood victims isolated on a patch of land 160 m below. The supplies should be dropped how many seconds before the plane is directly overhead?
September 21, 2010

5th grade
What is subject and verb of this sentence...The rest of story was never told.
September 20, 2010

english
What is the subject a d verb of this sentence...The rest of the story was never told.
September 20, 2010

math
Three different pairs of numbers that add together to get 1
September 20, 2010

molal
the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol. i tried to solve it on...
September 16, 2010

molal (again)
im not sure about the last step tho... i know the final answer is -120.0 but im not sure how to get to that...
September 15, 2010

molal (again)
i tried to solve it on my own but im confused about the last part, this i what i have so far.. moles of glycerin= 50.0/92.10=0.54 molality=0.54/0.200=2.7 is that right? im a little confused about the numbers im supposed to use for step 3... this was the question: the freezing ...
September 15, 2010

Chemistry
a car is traveling at a rate of 41.2 megameters/hr. what is the rate in cm/s?
September 15, 2010

Physics
An airplane flies 200 km due west from city A to city B and then 345 km in the direction of 32.0° north of west from city B to city C In straight-line distance, how far is city C from city A?
September 14, 2010

8th grade math
thanks
September 14, 2010

8th grade math
I need the equation for these numbers: 3, 9, 19, 33, 51 I see that the pattern goes up by 6, then 10, then 14, then 18 (4 more each time)
September 14, 2010

molal
Thank you for the help, i really appreciate it.
September 14, 2010

molal
the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol. any help would be ...
September 14, 2010

molal
i tried to solve it on my own but im confused about the last part, this i what i have so far.. moles of glycerin= 50.0/92.10=0.54 molality=0.54/0.200=2.7 is that right? im a little confused about the numbers im supposed to use for step 3...
September 13, 2010

molal
thank you looks like i double posted... sorry
September 13, 2010

molal
the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol. any help would be ...
September 13, 2010

molal
the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol. any help would be ...
September 13, 2010

college math
Given the situation described, identify the type of sampling involved. A parish in Louisiana is divided geographically into school districts. A random sample from each of the school districts is selected
September 11, 2010

english
Their are three kids in the room.
September 11, 2010

english
Sentence Correction and Changes in Writing
September 11, 2010

chemistry
density of 8.48 g/cm3 volume of 114.5 cm3 of brass
September 10, 2010

chemistry
Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 . A fitting composed of common brass has a total volume of 114.5 .How many atoms of copper does the fitting contain?
September 10, 2010

MATHS----Matrix
For a given square matrix A the predicted values of matrix B are: predicted B=A(A'A)^(-1)A'B why is the matrix C=A(A'A)^(-1)A' an idempotent and symmetric matrix? and is this matrix invertible?
September 8, 2010

math
Simplify. Your answer should contain only positive exponents. (when a number is between *__* its an exponent) 5y*-5* - ------- -u*5* v*-4* .(times) -uv*5* sorry if this is a bit confusing (hard to write this on a computer)
September 7, 2010

Statistics
20 percent of the interval
September 7, 2010

Physics
The diameter of some celestial body is 3080 km. What is the volume of this body? _____m3 How many of these celestial bodies would be needed to create a volume equal to that of Earth? The radius of the Earth is 6.38 106 m.
September 7, 2010

physics
The diameter of some celestial body is 3080 km. What is the volume of this body? _____m3 How many of these celestial bodies would be needed to create a volume equal to that of Earth? The radius of the Earth is 6.38 106 m.
September 6, 2010

eth/125
·Write a 700- to 1,050-word essay in which you answer the following questions: Conduct research to determine if the ethnic group colonized or if it immigrated to the United States. What country did they originate from and why did they enter the U. S.? Did the group face...
September 4, 2010

physics
A charge of -3.35 nC and a charge of -7.00 nC are separated by a distance of 40.0 cm. Find the position at which a third charge of +7.10 nC can be placed so that the net electrostatic force on it is zero.
September 3, 2010

math
If a vehicle gets 16 MPG and gas costs $2.70/gallon. How much would it cost to drive the vehicle 30 miles? Can someone help me find a formula to figure this out?
September 2, 2010

psychology
I was asked to define independant and dependant variables without defing, but buy using an example...would this be one...two digging dogs, one never corrected for digging(IV) and one corrected by a loud noise(DV), or would that be classical conditioning?
August 30, 2010

4th grade
Independent and dependent variables are related to one another. The Independent part is what you, the experimenter, changes or enacts in order to do your experiment. The dependent variable is what changes when the independent variable changes - the dependent variable depends ...
August 30, 2010

earth science
how do members of the biosphere affect the geosphere?
August 29, 2010

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