Saturday
December 3, 2016

# Posts by kristin

Total # Posts: 206

math
In a lottery game, a player picks 9 numbers from 1 to 43. How many different choices does the player have if order doesn't matter?
November 19, 2016

Chemistry
What is the standard cell potential of a cell made of theoretical metals Ms/Ma^+2 and Mb/Mb^+2 if the reduction potentials are -0.19V and -0.85 V, respectively? +0.66V -0.66V +1.04 V*** -1.04V
June 1, 2016

Chemistry
What symbol is used to show the standard reduction potential of an oxidation reaction in a half cell? The sub means what follows is a subscript So the 0 is a superscript and the sub is its subscript E^0 sub cell*** E^0 sub red E^0 sub oxid All of the above
June 1, 2016

Chemistry
To charge a lead storage battery you must apply a direct current to it. hold a magnet close to it. force alternating current through it.*** increase the pressure on it.
June 1, 2016

Analytical Chemistry
A 10.0 mL sample of whiskey was diluted to 500.0 mL. A 4.00 mL aliquot of the diluted sample was removed and the ethanol, C2H5OH, was distilled into 50.00 mL of 0.02150 M K2Cr2O7 and oxidized to acetic acid. The excess Cr2O72– was then back titrated with 17.1 mL of 0.1275...
October 18, 2015

Physics
Suppose you have a stack of 9 identical oak planks, each of which have a mass of 8.0 kg. You are required to pull the seventh plank from the stack (counting from the top). If the coefficient of friction between oak and oak is 0.6, how hard do you have to pull?
October 7, 2015

Physics
A block of mass 8.60 kg is pulled along a horizontal frictionless surface by a cord that exerts a force of 33 N at an angle 29.40 degrees from the horizontal. What is the magnitude of the normal force exerted on the mass by the floor? I solved for the acceleration, which was 3...
October 7, 2015

Math
The top of a tree makes angles s and t with Points K and L on the ground, respectively, such that the angles are complementary. Point K is x meters and Point L is y meters from the base of the tree. A)In terms of x and y, find the height of the tree. Include your work. B)If t...
September 10, 2015

Physics
You attach one end of a spring with a force constant k = 893 N/m to a wall and the other end to a mass m = 2.02 kg and set the mass-spring system into oscillation on a horizontal frictionless surface as shown in the figure. To put the system into oscillation, you pull the ...
April 22, 2015

Chemistry
In a solution of a weak acid and its conjugate base, which condition has to be true for pH to equal pKa? The concentration of acid has to be greater than the concentration of base. The concentration of acid has to be equal to the concentration of base. An indicator has to be ...
April 20, 2015

Chemistry
Calculate the hydronium ion concentration of blood which has a pH of 7.24. 7.17 x 10-4 M 5.75 x 10-8 M 1.15 x 10-7 M 0.86 M none of the above I had chose 1.15*10^-7 by doing the log equation -log(1.15...) and I but it goether with -log(10*^-7.24) and it was closest to 14 and ...
April 20, 2015

Chemistry
What is the pH of a solution which has hydroxide concentration, [OH-], equal to 7.6 x 10-4 M? 0.88 3.12 10.9 13.1 none of the above I had chose 3.12 for this one and this one was also wrong. I did this because I did the equation -log(7.6*10^-4) and got 3.12.
April 20, 2015

Chemistry
How many moles of chlorine are there in 16.0 mL of 0.450 M CaCl2? 0.0072 mol 0.0144 mol 0.0216 mol 0.0375 mol none of the above I had chose 0.0072 and had submitted it in my assignment, but it had said it was wrong. I chose 0.0072 because I did this equation: 16/ 1000*0.450 ...
April 20, 2015

Chemistry
I took it as 4.9 x 10^-10 was correct from what you said and when I chose that as an answer it said it was wrong?
April 20, 2015

Chemistry
Four sets of conjugate acid/base pairs and Ka of the acid are given. Which pair would be the best to form a buffer at pH = 9.2? You can use the Henderson-Hasselbalch equation to answer this question. HCNO/CNO- 3.5 x 10-4 HC2O4-/C2O4- 5.1 x 10-5 H2CO3/HCO3- 4.3 x 10-7 HCN/CN- 4...
April 20, 2015

Chemistry
The Ka for the reaction of acetic acid and water is 1.8 x 10-5. Which of the following statements is true at pH 7? A.) there is much more acetic acid than acetate ion B.) there is more acetate ion than acetic acid C.) the concentration of acetate ion is equal to that of acetic...
April 6, 2015

Chemistry
The ethylammonium ion, CH3CH2NH3+, has a pKa of 10.81. It reacts with water to form ethylamine, CH3CH2NH2 and H3O+. Which of the following statements is true at pH 7? A.) ethylamine predominates B.) ethylammonium ion predominates C.) the pH is higher than pKa of the ...
April 6, 2015

physics
A 0.205 kg bird flying along at 7.8 m/s sees a 0.029 kg insect heading straight toward it with a speed of 15 m/s (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch. What is the bird's speed immediately after ...
March 30, 2015

Statistics and Probability
Mallory has a credit score of 680 and she is offered and interest rate of 8.3%. is this a good offer? Explain your answer.
December 8, 2014

Algerbra math
(7x^2+3x+9)+(2x^2+5x-2)
October 1, 2014

Calculus
2x -------- (x-2)(x+2) using partial fractions That's supposed to be a division sign of some sort
May 22, 2014

Calculus
WHat?
May 21, 2014

Calculus
find the co-ordinates y=x(2-x) where the gradient is 2
May 21, 2014

Calculus
Where did -h come from
May 21, 2014

Calculus
1/X by first principles
May 21, 2014

Calculus
A fragment of bone is discovered to contain 20% of the usual carbon-14 concentration. Estimate the age of the bone to the nearest hundred years, given that Carbon-1 is radioactive with half-life of 5730 years and the rate of decay is given by the following differential ...
May 21, 2014

Calculus
What do you mean my discs and shells?
May 21, 2014

Calculus
Find the volume of the solid generated by rotating about the y axis the area in the first quadrant bounded by the following curve and lines. y=x^2, x=0, y=2.
May 21, 2014

Survey Math help
A movie complex has eight different movie theaters. The manager of the complex wants to conduct a survey to determine which snacks to add to the menu. Which represents the best sample the manager could use for the survey? Would I do specific ages the first 100 randomly picked ...
May 1, 2014

Coordinates Math"Steve"
Is the proportional? x: 1 3 4 6 y: -4 -12 -16 -24 I think it is. Am I correct?
April 25, 2014

Geometery help
Ok I will thanks guys.
April 25, 2014

Geometery help"Steve"
The point Q(x,y) is reflected in the origin. Use arrow notation to describe the original point and its reflection. I chose this: (x,y) to (x,y) Am I right?
April 25, 2014

Help me solve??
Thank you for the steps that helps so much/. Thank you Steve!
April 25, 2014

Help me solve??
XYZ has vertices X(5,6), Y(9,12), and Z(12,8). it is translated right 8 units and up 3 units. What are the coordinates of X', Y', and Z' ?
April 25, 2014

Math
If you put me into 7 equal groups with 3 in each group and 5 are left over, what number am I?
March 6, 2014

what??
im not trying to fool anything this is not a name change.MS.SUE Im not trying to be disrecptful since you do help a lot of kids but I also have talking to a lot of kids to and they say that sometimes your very rude and mean....im just trying the help the guy @mathhelp123 he ...
January 8, 2014

math
January 8, 2014

math
I don understand this either
January 8, 2014

math
I just saw this guy post this here and I think he needs help??? A recipe calls for 4 pounds of fruit.you have 60 ounces of fruit. A.do you have as much fruit as you need? B.if not,how much more do you need?
January 8, 2014

history
trouser wearing members of a revolutionary uprising of the french working class were called the___________?
November 29, 2013

history
the ____ act required king______ 1 to convene parliament every three years. is it parliament,king charles?
November 29, 2013

PHYSICS
Two 75 kg hockey players skating at 5.50 m per s collide and stick together. if the angle between their initial directions was 120 degress, what is their velocity after the collision?
November 5, 2013

Chemistry
Anhydrous aluminum oxide can be reduced to aluminum according to thisa chemical equation: 2 Al2O3 (s) ---> 4 Al (l) + 3 O2 (g) Calculate the mass of aluminum oxide reacted if 82 g of Al was produced and the percent yield was found to be 89.3%
October 18, 2013

Chemistry
What mass of copper(II) nitrate would be produced from the complete reaction of 65.3 g of copper, according to the chemical reaction shown below? Cu + 2 AgNO3 ----> Cu(NO3)2 + 2 Ag Use the masses to two decimal places using the periodic chart in the front of your text. ...
October 18, 2013

chemistry
a. How many atoms of hydrogen are in 25.0 g of ammonia (NH3)? Use the format 6.02E+23 for 6.02 x 1023 b. How many atoms of nitrogen are in the same amount of ammonia? Use the molar mass to two decimal places found on the periodic table in the front of your text.
October 18, 2013

calculus
Meg's pension plan is an annuity with a guaranteed return of 4% per year (compounded quarterly). She would like to retire with a pension of \$20,000 per quarter for 10 years. If she works 30 years before retiring, how much money must she and her employer deposit each quarter?
September 16, 2013

Chem
Caculate the volume of CO2 gas given off at 756 mm Hg and 23C when 150 kg of limestone(CaCO3) is heated until it decomposes according to the following reaction:CaCO3(s)=CaO(s)+CO2(g)
March 13, 2013

science
Which of the following is true about an object that floats in water? (1 point) The object is less dense than frozen water. The mass of the object is less than that of water. The density of the object is less than that of water. The volume of the water is greater than the ...
March 1, 2013

Physics
The focal length of the objective of a telescope is 0.2 m and the eyepiece has a focal length of 1.6 m. What is the length of the telescope? A. 1.8 m B. 1.4 m C. 1.6 m D. .90 m E. 8.0 m
January 20, 2013

english
Please help me write an essay. the question is "What do you think the theme is of Our Town and how is it shown?"
January 6, 2013

Math word problem
Patsy has cheerleading practice on every fourth school day. She wants to be in the school play, but they have practice on every sixth school day. If both started on September 5th, what would be the first date that she has to choose between cheerleading and play practice? I ...
December 5, 2012

statistics
First notice they gave you the mean, standard deviation, and an X value. Meaning you can you the formula I would also draw a distribution picture where the number will end up being. X = Z * (standard deviation) + (mean) Plug in the numbers: 130 = Z (20) + 100 Subtract 100 FROM...
November 7, 2012

Math help!
I got the same thing 3. our teacher we thought said to subtract the two middle and then divide it by two to get the median. We are confused.
October 10, 2012

Math help!
Mean 82 Median 3 Mode 81 The median? But I really do not understand it because it is such a low number? I am sorry I am trying to understand.
October 10, 2012

Math help!
It would have to be the median?
October 10, 2012

Math help!
The mean?
October 10, 2012

Math help!
Jack has the following scores on exams in his math class. 81, 87, 93, 89, 61, 81 If he wants to make his performance sound as good as possible, which measure should he use—the mean, the median, or the mode of his exam grades when he talks about how he is doing?
October 10, 2012

Math
oops! yes I forgot to divide by two! 19 is the median. And would that best represent the ages?
October 10, 2012

Math
so the mean is 16.75 The median is 12 right? Because I had to subtract the two middle numbers to get the middle number. The mode is 2 So would it be the median to represent the ages of the houses?
October 10, 2012

physics
The upward force is the same in both situations.
September 29, 2012

statistics
The average temperature in households is 67.6 degrees F. The standard deviation is 4.2 degrees F. A random sample of 51 households is to be selected What is the probability that the average of this sample will be within 1.4 STANDARD ERRORS of the population mean?
September 28, 2012

english
a good thesis statement on why teachers should have the authority to remove disruptive students from their classes permanently.
September 28, 2012

History
How did england change after its war with spain? and How did this change played a role and part in history by analyzing the magnitude and scope?
September 23, 2012

science
A conatiner filled with marbles weighs 435 grams. The container weighs 28 grams. What is the mass of the marbles?
September 18, 2012

education
I just need to know the steps required for a multicultural education to be effective
September 16, 2012

education
Read the following scenario: You are a second-grade teacher at Happy Valley Elementary School. You are teaching language arts and social studies. Your classroom of 21 students consists of 7 white students, 5 Latino students, 4 African American students, 3 Native American ...
September 16, 2012

Economics
2. If a firm increases all of its inputs by 60 percent and its output increases by 90 percent, then you know that: A) it is encountering diseconomies of scale. B) it is encountering economies of scale. C) it is encountering constant returns to scale. D) the marginal products ...
September 13, 2012

Economics
Suppose that a tour bus business incurred implicit costs of \$600,000 and explicit costs of \$7 million in a specific year. If the firm sold 125,000 tours at \$60 per person, its accounting: A) profits were \$100,000 and its economic profits were \$500,000. B) losses were \$100,000 ...
September 13, 2012

Chemistry
A rock sample contains only Sb2S3 and FeS. If 835g of the sample contains 11.2% antimony, what is the mass percent of the Sb2S3 in the sample? What is the mass percent of the sulfur in the sample? So far, I have determined that 11.2% of an 835g sample is 93.52g Sb, the molar ...
August 31, 2012

Chemistry
100 ml of 0.01N HCl is added to 0.9L of distilled water. What would the final pH of the solution be?
August 30, 2012

Introduction to HS
Ok, thank you very much for your help!!
July 25, 2012

Introduction to HS
I am having trouble with a question. In order to get an idea of significant subject areas in a chapter, it is best to read the. A. Subheads B. Graphics C. Captions D. Table of contents In my study guide it states : Read all the subheadings and sub-subheadings. These will give ...
July 25, 2012

1. Suppose quality control inspectors at the coffee house chain take a sample of 100 pieces of this chocolate product from an incoming shipment. They find a sample average of 60% cacao with a standard deviation of 8%. What is the standard error of the sampling distribution of ...
July 23, 2012

Chemistry
If you reclaim 0.250g Ag from AgNO3, how much AgNO3 did you have to begin with?
July 16, 2012

Physics
A 3.30-kN piano is lifted by three workers at a constant speed to an apartment 28.8 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 197 W of power, and the pulley system is 75.0% efficient (so that 25.0% of the ...
June 17, 2012

Physics
If a projectile is launched from Earth with a speed equal to the escape speed, how high above the Earth's surface is it when its speed is three-fifths the escape speed? I keep getting the answer 2.56x10^6 m after solving it a few different ways. Help would be great.
April 28, 2012

geometry
Factor 15x^2 - 8x - 16
March 8, 2012

algebra 2/math
how do i factor x^3+2x^2-x-2
February 29, 2012

algebra
X^2-4x=0
February 21, 2012

chemistry
design a simple lever that could be raised and lowered smoothly using niitinol wires.
February 16, 2012

phyisics
a= (4pi^2r)/T2 =(4pi^2(50))/(14.3)^2 =9.7 m/s^2
February 14, 2012

Physics
A driver in a car traveling at a speed of 56.0 mi/h sees a deer 116 m away on the road. Calculate the minimum constant acceleration that is necessary for the car to stop without hitting the deer (assuming that the deer does not move in the meantime).
February 2, 2012

AP Chemistry
This is part of a marathon problem, we have to identify the five compunds of H, N, and O described below. For each compound, I have to write a Lewis structure that is consistent with the information given. a.) All the compunds are electrolytes, although not all of them are ...
December 4, 2011

Physics.
What is the transfer mechanism of energy, momentum, and angular momentum?
November 27, 2011

gets larger?
November 27, 2011

suppose you have 2 cars, and the larger one is twice as massive as the smaller one. If you and a friend push on them so that their accelerations are equal, how must the forces applied to the cars compare? a. the force on the larger car is equal to that on the smaller car. b. ...
November 27, 2011

algebra
Suppose D=(w+2)(w-3)(w+6).For what three values of w will D have a value of 0?
November 21, 2011

Chemistry
If solution A had a pH of 8, and solution B had 1,000 times this hydrogen ion concentration what would be the pH of solution B, and would solution B be acidic or basic?
November 14, 2011

trig
find the coordinates of the terminal point on the unit circle determined by t=9pt/7 to two decimal places
November 13, 2011

Physics
The position vector r of a particle moving in an xy plane is given by [r = (6t^3-3t)i + (4-1t^4)j] with r in meters and t in seconds. What is the angle between the positive direction of the x axis and a line tangent to the particle's path at t = 3 s? Give your answer in ...
September 25, 2011

Math
To subtract 91 from 99, do you need to regroup? Explain
September 19, 2011

Math
To subtract 91 from 99, do you need to regroup? Explain
September 19, 2011

3rd math
Bethany has 40 apples. Write a subtraction story about the apples that would require regrouping. Then write the answer in a complete sentence.
September 19, 2011

physics
a rocket blasts off and moves up with an acceleration of 12 m/s2 until it reaches 30 m then the engine shuts down and the rocket continues in free fall. What is the max hieght of the rocket and what is the total duration of the rockets flight?
August 31, 2011

biology
Vaccinate 50 of the rats then expose only the 50 vaccinated rats to the disease
July 31, 2011

chemistry
When 0.100 mol of carbon is burned in a close vessel with 8.00g of oxygen, how many grams of carbon dioxide can form?
July 24, 2011

grammar
A Superblade was used at the 2 o'clock position, and the anterior chamber was entered was used is a verb ,was entered is also a verb ,am i right
June 15, 2011

Thermodynamics
An intrepid explorer takes 400 g of ice from the cold Siberian environment, where the temperature is –40 degrees and places it in a kettle inside his mobile laboratory. The ice melts and he heats the water to +40 degrees. What is the total amount of heat absorbed by the ...
June 6, 2011

algebra
simplify and write using only positive exponents. thanks. (2x^3y^4)^-2 divided by (8xy^6)^-3
May 25, 2011

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