# Posts by Lisa

Total # Posts: 3,427

AP Chem
Is that because it's a solid and not a gas?

AP Chem
For the following equilibrium system, which of the following changes will form more CaCO3? CO2(g) + Ca(OH)2(s) <--> CaCO3(s) + H2O(l) deltaH(rxn) = -113 kJ My choices are: a) Decrease temperature at a constant pressure (no phase change) B) Increase volume at a constant ...

n/4+32=72 (sub. 32) n/4=40 (multiply by 4) n=160

Multiply both sides by 4

Chem Help!!!!
I balanced the equation and got 2Cr+3O2->2CrO3.. but I was informed that this is the incorrect answer

Chem Help!!!!
In an experiment, 0.771g Cr(s)reacts completely with 0.712g O2 to form a single solid compound. Write a balanced equation

Chemistry Help!!!!!
How many milliliters of 0.635M K2CrO4 are needed to precipitate all the silver in 410mL of 0.158M AgNO3 as AgCrO4 ?

calculus
At noon, you and I start at the same place, and then you head east at a speed of 5 kilometers per hour, and I head north at a speed of 4 kilometers per hour. After two hours, how fast are we moving apart, in kilometers per hour?

Microeconomics
Thanks, Anonymous...Although I understand the concept I need to actually see the formula. I am a visual kindda person.

Microeconomics
If fixed cost is \$8,000, variable cost is \$5,000 at an output of 2 and \$9,000 at an output of 3, how much is marginal cost at an output of 3? Can someone show me how to do the formula step by step?

Fill in the blank 1-2. Although Jenny chose the songs from her __ that she knew best, she wasn't complacent about being prepared. Afraid she would __ the night of the concert, she practiced the songs over and over. 3-4. The __ of the lecture was that although the United ...

Is this a correct sentence? The gist of the lecture was that although the United States encourages free trade, some other countries falter it

Math help
the answer is 40 years. Hope this helps

1. repertoire 2. hamper 3. gist 4. falter 5. variable 6. conducive 7. frenzy 8. paradox 9. bizarre 10. flaunt

Can you help me with the following sentences? 1-2. Although Jenny chose the songs from her __ that she knew best, she wasn't complacent about being prepared. Afraid she would __ the night of the concert, she practiced the song over and over. 3-4. The __ of the lecture was ...

math
Thank you c:

math
oh because i thought it was a negative and a positive so they cancel out but its 7x^2-6x-6? or...?

math
so would it be 7x^2-6??

math

Chemistry
Thank you

Chemistry
A thoroughly dried 1.281g sample of Na2SO4 is exposed to the atmosphere and found to gain 0.383g in mass. What is the percent, by mass, of Na2SO4*10 H2O in the resulting mixture of anhydrous Na2SO4 and the decahydrate

Pre Cal
Sec^2 2u-1/Sec^2 2u = Sin^2 2u

MaTH
the perpendicular line is -2 the parallel line is 3/2

Chemistry
A 62g piece of ice at 0 degrees celcius is added to a sample of water at 9 degrees celcius. All of the ice melts and the temperature of the water decreases to 0 degrees celcius. How many grams of water were in the sample

English
Are there cultures that should not be promoted in the early childhood education setting? Why or why not? Support your position.

algebra

math
75

math
if the ratio of boys to girls is 3/4 and there are 49 students how many boys are there?

ok thanks

Is the correct answers 4. empathy 6. complacent 9. diligent 10. transcend

Is this the correct word for each sentence 1-2. Lynn begged the bank to __ the overdraft charge of thirty dollars, telling them that it would entirely __ her savings. 3-4. In high school, Julio was voted "Most Likely to Become a Psychologist." It was the __ of his ...

Chem Help!!!!!
Ha! I just saw your comment... I am indeed are you in his class or you've taken him before, Donovan?

Chem Help!!!!!
The angle iron pictured here is made of steel with a density of 7.78g/cm^3. (Figure 1) measurements are: 12.78cm 10.26cm 1.35cm 2.75cm 1.35cm

College Physics 2
A parallel-plate air capacitor is made from two plates 0.250 m square, spaced 0.70 cm apart. It is connected to a 140 V battery. a) What is the capacitance? C = 7.90×10−11 F b) What is the charge on each plate? Enter your answer as an absolute value of charge. Q = ...

accounting
Suppose that two years after the bonds were issued, the required interest rate fell to 7 percent. What would be the bonds’ value?

In portfolio analysis, the goal when purchasing leverage items is

algebra
8/3fg^2

Chemistry
I read this question wrong and posted it wrong...it should be which is incorrect? If this is the case shouldn't C be the correct one?

Chemistry
Consider the following equilibrium: NH4Cl(s)--->NH3(g) + HCl(g) Suppose a vessel containing NH4Cl(s), NH3(g) and HCl(g) is at equilibrium. If the volume of vessel is instantaneously doubled while keeping the temp constant when a new equilibrium is reacted, which of the ...

Math
x+ .76x =1.76x Or 1x+.76x=1.76x

Math
.76(.0200-x)=x .0152-.76x=x +.76x +.76x (x add to .76x = 1.76x) .0152=1.76x (divide by 1.76 to solve for x)

math
6x=-36 /6 /6 x =-6

CHEM
How many grams of magnesium chloride are needed to prepare 100ml of a 0.325 M MgCl2 solution?

CHEM
What is the molarity of potassium iodide solution prepared by adding 5.810g of KI to sufficient water to make a final solution volume of 250.0mL?

CHEM
What is the molarity of a calcium sulfate solution prepared by adding 27.89g of CaSo4 to sufficient water to make a final solution volume of 1.00L?

CHEM
How many grams of sodium chloride are required to prepare 1.00 liter of a 1.00M NaCl solution?

math
9*12=108 W+(w+44)=108 2w=64 W=32. -white roses

math
X+y=54 5x+20y=780 -5(x+y=54) -5x-5y=-270 5x+20y=780 15y=510 Y=34 X=20 5(20)+20(34)=780 Five dollars bills = 20

Algebra 1- Math
2x-3y =-3 -1(3x-3y=18) 2x-3y=-3 + -3x+3y=-18 (add two equations) -x = -21 x = 21 2(21)-3y =-3 42-3y=-3 -3y=-45 y=15

math
A man sells a nut mixture consisting of 1/3 pecans and 2/3 cashews. Pecans cost 3 times as much as cashews. if a pund of the mixture costs him \$0.40, how much did he pay for a pond of cashews? a pound of pecans?

Physics
In a baseball a pitcher can accelerate a .15kg ball from rest to 98 mi/h in a distance of 1.7m a) what is the average force exerted on a ball during a pitch? b)If the mass of the ball is increased, is the force required of the pitcher increased, decreased or unchanged?

MATH
7s-5s+10<30 -10 -10 7s-5s < 20 2s < 20 \2. \2 S. < 10

Math
Tom spent 1/3 of his allowance at mall. Of the money he spent at the mall, he spent 3/5 of it on jeans. What fractions of his allowance did Tom spend on jeans?

Algebra
W(w+4)=77 W^2 + 4w - 77 = 0 (W-7)(w+11)=0 W-7=0 W=7 W+11=0 gives neg. ans. Length = 7+4=11 Width = 4

physics
a mass m=8 kg sits on top of an h=1.8 m high table. The angle of the ramp is theta= 35 degrees. What is the length of the ramp.

Thanks

Do you have a copy of the sentence check 2 questions for chapter 20 in the 4th edition of Improving Vocabulary Skill book by Sherrie L. Nist?

CHem Help!!!!
What Celsius temperature will the Fahrenheit thermometer be 4-times more than on the Celsius thermometer?

Chem Help!!!!
I just need a solution to the first half of the question I figured out the 2nd half

Chem Help!!!!
What Celsius temperature will the Fahrenheit thermometer be 4-times more than on the Celsius thermometer? At what Celsius temperature will the numerical reading on the Fahrenheit thermometer be 1/9 that on the Celsius thermometer?

Chem Help!!
thank you

Chem Help!!
A standard 1.000kg- mass is to be cut from a bar of steel having an equilateral triangular cross section with sides equal to 3.00in. The density of the steel is 7.70g/cm^3. How many inches long must the section of bar be?

Chem Help!!
ok cool thanks for your help

Chem Help!!
After I multiplied by 2 I got a final answer of 0.000556mm

Chem Help!!
When I converted with Devron method I got 27.8*10^-6mm When I did it Bob's way I got 27.8*10^-5 is this correct?

Chem Help!!
The volume of a red blood cell is about 90.0*10^-12cm^3 Assuming that the red blood cells are spherical, what is the diameter of a red blood cell in millimeters?

Chemistry
thank you

Chemistry
20.02cm*

Chemistry
The density of aluminum is 2.70 g/cm^3. A square piece of aluminum foil, 20.02 on a side is found to weigh 2.573g. What is the thickness of the foil, in millimeters?

Chemistry
when I was copying and pasting the problem the units and numbers did not transfer... I completely understand that you need these units

Chemistry
The density of aluminum is . A square piece of aluminum foil, 20.02 on a side is found to weigh 2.573 .What is the thickness of the foil, in millimeters?

Chemistry
1.006 g/ml 4.7% acetic acid by mass 3.00L

Chemistry
A vinegar sample is found to have a density of 1.006 and to contain 4.7 acetic acid by mass.How many grams of acetic acid are present in 3.00 of this vinegar?

Chemistry
Hey I tried that and still cant get the right answer. The answer that I got is 555.6 or 556 K and its not correct. What answer did you get?

Chemistry
At what temperature will the rate constant for the reaction have the value 6.5×10−3 M/s? (Assume k = 5.4 * 10^-4 M/s-1 at 599K and k = 2.8 * 10^-2 M/s at 683K .)

Chemistry
I am trying to determine which protein (in a given list) will stick most tightly to a cation exchange column at pH 7. I am unsure how to go about solving this.. We are given molecular weight, isoelectic point, and number of subunits for each protein. Where should I begin?

Chemistry
I am trying to determine which protein (in a given list) will stick most tightly to a cation exchange column at pH 7. I am unsure how to go about solving this.. We are given molecular weight, isoelectic point, and number of subunits for each protein. Where should I begin?

goven
Which one of the following is NOT widely regarded as a political ideal in America?

In questions 3 and 4 would the correct answer be: 3 prone , flippant 4. perception, impasse

Is question 3 and 4 correct

3.impasse, flippant 4. prone, perception

word choices: congenial, prone, flippant,rapport, impasse, rationale, perception, relentless, prompt, reprisal 1.Because Wade is so congenial and easy to talk to, we established a warm rapport the first day we met. 2. Although the company president explained rationale behind ...

Can you help me with the sentence check 2 Chapter 17 and 18 in the improving vocabulary skill workbook?

math
you fill up 40 gallon pool putting in 2 gallons water every minute, if someone scoops out 1 gallon every 8 minutes, how long would it take to fill the pool?

science
When you hit a nail into a board using a hammer, the head of the nail gets warm. In terms of kietic and thermal energy, describe why you think this happens.

calculus
Let f(x)=(2+x)2−4x. Note that f(x) is undefined at x=0. However, in this case, we can find a continuous function g(x) defined at x=0 that agrees with f(x) near x=0. Find the function g(x) that is equal to f(x) when x≠0 such that g(0)=limx→0f(x).

calculus
Let f(x)=x2+x−6x−2. Note that f(x) is undefined at x=2. However, in this case, we can find a continuous function g(x) defined at x=2 that agrees with f(x) near x=2. Find the function g(x) that is equal to f(x) when x≠2 such that g(2)=limx→2f(x).

math
A pattern for curtains calls for 2/3 of a yard of material. You want to shorten the curtains to2/3 of the height of the pattern. How much fabric is needed?

Calculus
Use a trig identity to combine two functions into one so you can solve for x. (The solution should be valid for any value of t). 3cos(t) + 3*sqrt(3)*sin(t)=6cos(t-x) I know that 6 cos(t-x) can be 6(cos(t)cosx(x)+sin(t)sin(x)) I don't know where to go from there though.

Calculus
In these complex exponential problems, solve for x: 1)e^(i*pi) + 2e^(i*pi/4)=? 2)3+3=3i*sqrt(3)=xe^(i*pi/3) MY attempt: I'm not really sure of what they are asking. For the 1st one I used the e^ix=cos(x)+i*sin(x) and got -1+sqrt(2) +sqrt(2)i 2) I solved for x and fot (3+3i...

chemistry
okay thank you very much :)

chemistry
thanks for the help i really appreciate it :D

chemistry
i know how to grapgh it and all i am only stuck with how to find the intial molar concentration. i believe you're telling me the step to finding the ka value. sorry i am a little confused with this

chemistry
the data is Vol. of NaOH added 0 1 2 3 4 5 10 15 20 21 22 23 24 25 26 27 28 29 30 35 40 45 50 pH 2.92 3.47 3.79 3.98 4.13 4.25 4.67 5.03 5.57 5.72 5.91 6.23 8.78 11.29 11.59 11.75 11.87 11.96 12.22 12.36 12.46 12.52 this is the data and this was given

chemistry
so this is the question: you will be given a sample of nictinic acid with an unknown concentration, and it will be titrated with 0.100M NaOH. instead of measuring the volume of the basic solution required to reach the endpoint, however, you will measure the pH. Then you will ...

chemistry
the chemical equation of nicotinic acid is C5H4NCOOH + NaOH --> C5H4NCOONa + H2O i need to calculate the intial molar concentration of this acid, based on the ratio in which the acid and base react. Please help i cant figure it out,

Physics
Stand two plane mirrors on their edges and parallel to one another. Place a coin between them near one end. How many images do you see? Draw a ray diagram to explain the formation of the images.

Physics
Stand two plane mirrors on their edges and parallel to one another. Place a coin between them near one end. How many images do you see? Draw a ray diagram to explain the formation of the images.

Chemistry
What is the mass of water that can be heated from 39 C to 80 C by the combustion of 150 g of methane. CH4 + 2O2 => CO2 + 2H2O Delta H= -890kJ

Chemistry
a)vii b)i

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